Only fairly recently scholars have begun to reassess Spinoza’s last work, the TP. It is in that unfinished treatise that Machiavelli’s legacy figures prominently. In the final section of Chapter 5 Spinoza praises him as “very sharp-witted [acutissimus],” “wise [sapiens],” and “most prudent [prudentissimus].” Given the exemplary part played by the wise man (vir sapiens) in Spinoza’s Ethics (E5pref, E5p42s), this is certainly significant. The only other people called “wise” by Spinoza are Solomon (TTP2.1, 3.5, 4.40, 18.18) and Thales of Miletus (Ep44). Furthermore, in TP10.1 Spinoza paraphrases a passage in Machiavelli’s Discourses (3.1), throwing in a literal quotation to boot. The inventory of his library, made after Spinoza died, shows that he had the collected works of Machiavelli in Italian on his bookshelves, plus a separate Latin edition of The Prince.

So Machiavelli did indeed leave his mark on Spinoza’s thought. It remains difficult, however, to establish what he owed directly to Machiavelli, and to determine when he read The Prince, the Discourses, and On the Art of War. That he had studied these works by Machiavelli when he wrote the TP (1675–76) is clear, but what about the earlier TTP? Several conceptual and terminological similarities between the TTP and Machiavelli’s Prince and Discourses have been taken as indications that Spinoza was already familiar with these texts by the mid 1660s. Thus his use of the history of the Hebrews is reminiscent of the way Machiavelli handles Roman history. In TTP18.30 Spinoza rejects regicide, and in TP5.7 he explicitly cites Machiavelli when he restates this point. A specific expression like “introducing religion into the state” (TTP19.53) occurs in a similar context in Discourses 1.11. Such Machiavellian elements in the TTP, however, need not prove straightforward borrowing. Spinoza may well have found them in the writings of Johan and Pieter de la Court, Franciscus van den Ende and others: his library contained many books in which he could have encountered Machiavellian ideas (see Morfino Reference Morfino2002, appendix, 242–66). Moreover, Spinoza knew Van den Ende and probably also Pieter de la Court personally.

In the TP, Spinoza praises Machiavelli as an advocate of freedom. This republican interpretation of Machiavelli was widespread in the seventeenth century (see Skinner Reference Skinner1981; Bock, Skinner, and Viroli 1990, esp. 121–41; Rosenthal Reference 601Rosenthal and Melamed2021). Machiavelli’s position is also relevant for the specific focus of the TP on stability and security. Both thinkers deal with the role of religion in the state, and Spinoza appreciates the Florentine’s pragmatic approach: a religion is good if it helps strengthen society; even if rulers do not believe in it themselves, they should still foster it (Gallicet Calvetti Reference Gallicet Calvetti1972, 82–100). Further similarities can be found in their criticism of employing mercenaries (though Spinoza does allow for mercenaries in some situations) and their pleas for conscription. The realistic perspective of Spinoza’s TP, as set forth in the opening paragraphs, chimes in with an equally famous passage in Chapter 15 of The Prince, even though there are no literal correspondences. Stating that politicians have written more successfully than philosophers about politics, Spinoza surely had Machiavelli in mind. They share a dispassionate approach to politics. Machiavelli and Spinoza are modern political thinkers, in that they analyze collective human behavior as a struggle for power. Given the passionate nature of human beings, society is “always a balance between forces of self-assertion” (Hampshire Reference Hampshire2005, 142). For both, this entails an emphasis on institutions (cf. Walther Reference Walther2018, chap. 8) rather than on individuals, and the need for checks and balances. The behavior of political leaders should not depend on their individual intentions. Instead, laws and social institutions must be devised in such a way that the acts of all the people involved (rulers and subjects alike) contribute to social stability and security.

So far we have looked for parallels mostly in the political theories of Machiavelli and Spinoza. They also appear to converge on a deeper level, namely on a notion of “power” that underlies their philosophies. This comes out clearly in their treatment of virtue. Virtus is a key concept in the Ethics, where it is closely connected with Spinoza’s theory of conatus, the universal striving of everything that exists to persevere in its being (see E5p25d, where the mind’s virtue is equated with its power, nature, and striving). In classical Latin the word virtus has the sense of ‘strength, vigor, power,’ and it is associated with manliness (vir means “man”) and courage. Cicero used virtus to translate the Greek notion of aretè (“goodness”), and in Christian thought the Latin term was narrowed down to the ethical notion of “virtue.” Renaissance authors like Petrarca, however, returned to its original classical acceptation of “power, strength.” It is in Machiavelli’s thought that virtù in that specific sense acquires a systematic function, with fortune (fortuna) as its counterpart. Together these terms express the tension between the political order and the chaotic world that is to be brought under control. In Ethics Part 4, Spinoza equates virtue with power (E4def8) and conatus (E4p22c), preparing a remarkable turn to politics in E4p37s2: though human beings are inexorably subject to affects and thereby often in conflict with one another, they can live harmoniously as citizens in a society that is maintained by laws. Spinoza may have been studying Machiavelli’s works in more detail after having finished the TTP, in which he developed his own theory of the affects in relation to politics. When he took up his work on the Ethics again in 1670, he recast the final parts into Parts 4 and 5 of the Ethics as we now know them. It is only then that the conatus, which already figures in the early KV (1.5), is firmly connected to both power and virtue. The link may have been inspired by Machiavelli’s notion of virtue.

Moses Maimonides (Moshe ben Maimon), one of the giants of medieval Jewish philosophy and a leading authority on Jewish law (halakhah), was born in Córdoba around 1138 and died near Cairo in 1204. Maimonides worked as a physician, served the Jewish community as a teacher and rabbinical judge, and became the head of the Egyptian Jewish community. Maimonides’ influence on Spinoza was considerable. Spinoza cites Maimonides’ Book of Knowledge almost verbatim and the Ethics and the TTP confirm Spinoza’s broader knowledge of Maimonides’ views.

Maimonides’ major philosophical work, The Guide of the Perplexed, is addressed to a sophisticated student who struggles to reconcile philosophical ideas with the Torah. The work reflects Maimonides’ familiarity with Aristotelian and Neoplatonic philosophy in Arabic, and it becomes a touchstone for subsequent Jewish philosophers. The Guide was also read closely by Thomas Aquinas and other Latin authors, and Maimonideans such as the Kimhis were important to the history of Christian Hebraism.

Maimonides’ major halakhic work is the Mishneh Torah, which systematizes and codifies Jewish law. The first book of the Mishneh Torah, the Book of Knowledge (Sefer haMada), includes important discussions of philosophical topics such as cognition and God. Maimonides also wrote a commentary on the Mishneh. His introduction to the tractate Ethics of the Fathers joins Aristotelian psychology and ethics (familiar to us from the Nicomachean Ethics, which Maimonides read in Arabic, and mediated for Maimonides by al-Farabi’s interpretations) with rabbinic views; key topics include human perfection, prophecy, and freedom. Maimonides’ other works include a treatise on logic; rabbinic rulings; public letters on important political and religious issues of the day; and medical works. The Guide and most of Maimonides’ works were written in Judeo-Arabic; the Mishneh Torah was written in Hebrew.

Spinoza owned a copy of the Guide in Samuel Ibn Tibbon’s 1204 Hebrew translation (Bragadin, Venice 1551). The Guide was normally studied and therefore printed with commentaries, some more oriented to rabbinic teachings, others more philosophical in character. Bragadin’s edition featured commentaries by two Spanish commentators, the converso Efodi (also known as Profiat Duran) (c. 1350–1415) and Joseph ben Shem Tov ibn Shem Tov (fl. 1461–89), each of whom had extensive knowledge of previous commentators (e.g., Jewish Averroists such as Joseph Ibn Kaspi and Moses of Narbonne). The Guide was also available in Latin in the mid seventeenth century; Buxtorf’s new translation appeared in Basel in 1639.

As Maimonides’ own introduction to the Guide emphasizes, the pedagogical style of the text is extremely challenging. Maimonides points us to the intrinsic difficulty of metaphysics as a subject and to the need to transition from imaginative to genuinely intellectual thinking. These demands lead him to make extensive use of contradiction, paradox, elliptical style, and non-linear presentation. Many chapters of the Guide are devoted to Maimonides’ clarification of biblical language and the elimination of improper ideas of God; others discuss philosophical issues in detail; yet others discuss Jewish law. Core themes in the Guide include a critique of language as imaginative, which leads Maimonides to non-literal biblical hermeneutics, particularly to an appreciation and intricate use of parables, metaphor, and equivocity; a radical rejection of all anthropomorphic conceptions of God in favor of negative theology; the distinction between imagination and intellectual knowledge on the one hand and between demonstrative and properly intellectual or intuitive knowing on the other; the nature of human knowledge and its limits; views of the creation or eternity of the world; miracles; the nature of prophecy, particularly Moses’ prophetic communal leadership, and human perfection; the immortality of the soul; providence; and ritual law and observance. Given the textual complexity of the Guide, Maimonides’ actual views on some of its topics, such as the creation or eternity of the world and the exact relationship of God and nature, remain under discussion by contemporary scholars.

Maimonides’ approach to Jewish law and his philosophical ideas were criticized by prominent scholars and rabbinic authorities during and after his lifetime. After the Guide was translated into Hebrew, Maimonidean controversies increased in France and Spain and continued for roughly one hundred years. At various times, some Jewish authorities banned the Guide and prohibited the study of philosophy, only to be countermanded by Jewish authorities in other places. At issue were, broadly speaking, the compatibility of Graeco-Arabic philosophy with religious life and the status of communal authorities. These controversies notwithstanding, as well as actions by Christian authorities (e.g., bans on Aristotelian philosophy in 1201 and 1231, the Albigensian or Cathar Crusade, and the burning of the Talmud in Montpellier or possibly Paris in the mid thirteenth century), Jewish philosophers continued their critical and constructive engagements with Maimonides’ oeuvre. Major figures in this history include Gersonides and Crescas, to whom Spinoza explicitly refers.

Spinoza’s relationship to Maimonides is intricate, nuanced, and ambivalent; the Ethics and the TTP in particular exhibit a mixture of intellectual affinity, even inheritance or appropriation, philosophical divergence, and profound critique. The two thinkers are separated by different horizons in physics, astronomy, and cosmology; Spinoza writes after Copernicus, Kepler, and Galileo and responds to Cartesian and Hobbesian physics. The two thinkers’ political circumstances are quite different as well.

Loci classici for considering Spinoza’s relationship to Maimonides in the Ethics are E2p7s, which concerns substance and its attributes, the nature of thinking, and the relationship of God and nature, and Spinoza’s theory of the eternity of the mind as presented in the latter portion of Part 5. In E2p7s, Spinoza observes that “some of the Hebrews” saw “as if through a cloud” the identity of “God, God’s intellect, and things understood by him.” Their affirmation of the Aristotelian idea of the union of the knower and the known in knowing (De Anima iii.4, Metaphysics xii.7, 9), according to Spinoza, anticipated his own view that “thinking substance and extended substance are one and the same substance, which is now comprehended under this attribute, now under that.” Maimonides is surely one of these Hebrews. Spinoza, in CM2.6, quotes part of Maimonides’ analysis of Aristotelian noetic union in Book of Knowledge ii.10 ; Guide i.68, a more elaborate discussion of the same idea, is another obvious source. The principal “cloud” is arguably Maimonides’ insistence on divine transcendence, creation, a hierarchical cosmos, and incompatibility of divinity and matter. Guide iii.32, which directs readers to contemplate “the divine actions, I mean to say the natural actions,” anticipates Spinoza’s famous Deus sive Natura; the question for interpreters is the distance from one formulation to the other.

In Part 5 of the Ethics, Spinoza’s relationship to Maimonides is evident in his account of the eternity of the mind and his key notion of the intellectual love of God (amor dei intellectualis). In the Guide, Maimonides analyzes both the human experience of providence and the nature of the immortality of the soul in terms of intellectual apprehension of nature and God and love of God. Each is proportionate to intellectual achievement: the more we know, the more we experience providence and love (Guide iii.17–18, iii.51), themes that find echoes in Spinoza in E5p23–42.

In broader terms, Spinoza’s emphasis on the distinction between imagination and understanding, and the pivotal importance of not substituting the former for the latter (e.g., E1p8s2, E1p15s), also echoes his predecessor. Both regard imagination as a power of the mind whose products require critical analysis. Where imagination reflects individuals’ idiosyncratic histories and the limits of the human body, leading to confusion and confabulation, the intellect, in contrast, apprehends the necessary order of nature (see, e.g., Guide i.34 and E2p18s). Like Maimonides, too, Spinoza differentiates between demonstrative reasoning (the second kind of knowing) and intellectual apprehension (the third kind of knowing); the former is a necessary but not sufficient condition for the latter, and indeed both underscore the power and the limits of demonstrative knowing. Similarly, Spinoza’s interest in pedagogy (TIE) and his awareness of relationship between affect or desire and the capacity to learn (Ep9) have a Maimonidean flavor (see the Epistle Dedicatory and Introduction to the Guide, and Guide i.34). Like Maimonides, Spinoza recognizes the simultaneity and sameness of affect and cognition; just as there is no dualistic split between thinking and Extension, there is no dualistic split between thinking and affect or desire. Finally, Spinoza’s analysis of good and bad as merely imaginative and conventional (E1app, E4p8–9, E4p68), rather than intrinsic, categories concurs not merely with Hobbes, but with Maimonides, whose view is mainstream among Jewish and Islamic Aristotelians (see Guide i.2).

In the TTP, Spinoza’s ambivalence about Maimonides is especially clear. Spinoza’s emphasis on the imaginative character of prophecy is clearly a criticism of Maimonides’ own view of prophecy as an overflow from intellect to imagination and thus as a mediation or interpretation of divinely received knowledge (e.g., TTP1–2; Guide ii.47). Spinoza denies the intellectual dimension of prophecy, retaining only the idea of prophecy as imaginative communication about the world. Yet Spinoza’s general emphasis on the political, legislative character of Mosaic prophecy comports with Guide ii.40 (some key passages are found in Spinoza’s discussion of Moses’ authorship of the legal portion of the Bible in TTP8, as well as in his analyses of Moses’ exceptional political skill in TTP5 and TTP17). TTP7, Spinoza’s central chapter on the scientific interpretation of Scripture, sharply criticizes Maimonides’ embrace of allegorical reading as a way to reconcile philosophical speculation with biblical texts. Quoting Guide ii.25 at length, Spinoza charges that Maimonides’ philosophical hermeneutics, far from assuring the integrity of Scripture, actually undermines its meaning by insisting on its truth and leads to political malpractice. Allegorical reading directs readers’ attention away from the universally accessible, reasonable ethical teachings found in Scripture, and, by insisting on what lies beyond the letter of the text, it empowers an interpretive clerical elite. Far from enhancing the public good, Spinoza argues, such elites prove themselves resourcefully self-serving and destructive to civil peace. Rather, then, than reinterpreting Scripture to comport with what we understand as true in physics and metaphysics, Spinoza argues that we should investigate, as far as we are able, the historical context and language of Scripture so as to understand the distinctive worldviews and teachings of its various authors and editors (see, e.g., Spinoza’s remarks on Joshua 10 in TTP2). Ultimately, then, for Spinoza, Scripture offers ethical and political advice and lessons drawn from the history of ancient Israel, not metaphysical insights or a science of nature.

Yet, for all his criticisms, Spinoza does not side with Maimonides’ anti-philosophical detractors. TTP15 charges a minor figure in the Maimonidean controversies, Judah Alfakar, with promulgating a non-rational view of nature and a fundamentally anti-intellectual posture. Alfakar may well be a stand-in for figures in the Dutch Christian scene. Strikingly, however, and in a manner reminiscent of Maimonides’ own insistence that properly prepared readers will find their way through the Guide and experience intellectual insight for themselves, Spinoza leaves it to the reader to navigate between the excesses of Maimonides and his opponents. Most important, Spinoza leaves it to his own readers to reflect on his own points of proximity to and distance from Maimonides on matters of psychology, cognition, metaphysics, ethics, and politics.

In the first half of 1841, the young Karl Marx read the TTP in the Berlin university library and by hand copied a large selection of passages; extensive quotations from Spinoza’s letters can also be found in Marx’s notebooks from that time (albeit in a different handwriting, so most likely the notetaking was commissioned by Marx). Since this was an extremely formative time for Marx, leading up to the first formulation of his own political philosophy in his struggle with Hegel and Feuerbach only a few years later, it is tempting to assume that his encounter with Spinoza had a lasting impact. But Marx’s published works rarely if ever explicitly mention Spinoza, and in the Holy Family he unspecifically groups him with Descartes, Malebranche, and Leibniz. Some quotations in Capital volume 1 are of similarly only occasional nature, including the occurrence of the methodological principle determinatio est negatio that also appears like a nod to Hegel.

For the first generation of Marxists, however, the general importance of Spinoza for the Marxist system seemed rather evident. Friedrich Engels is said to have conceded in a conversation with the Russian revolutionary, philosopher, and Marxist theoretician Georgi Plekhanov in 1889 that on the fundamental philosophical question of monism, “sure, the old Spinoza was completely right” (cited in Thalheimer and Deborin Reference Thalheimer and Deborin1928, 7). Marking the 250th anniversary of Spinoza’s death in 1927, the Soviet philosopher Abram Deborin acknowledged him as “a great materialist thinker” and “predecessor of dialectical materialism,” whose only legitimate heir is the “modern proletariat” (Thalheimer and Deborin Reference Thalheimer and Deborin1928, 74).

Marxist orthodoxy accordingly has often kept alive a certain image and knowledge of and respect for Spinoza, and orthodox Marxists have contributed to Spinoza scholarship, in particular by placing him and his work firmly in his historical times and social conditions of the Dutch “Golden Age,” an exceptional moment of early trade capitalism (cf. Feuer Reference Feuer1958). At times, this orientation had produced frictions with the official party line, for instance, during the temporary success of Maoism in Western Marxism in the late 1960s and early 1970s that coincided with certain Spinozist preoccupations (cf. Moreau Reference Moreau1975), and in some philosophical debates in the late GDR where the appeal to freedom and rationality could seem subversive, given the existing social structures (cf. Seidel Reference Seidel and Caysa2009).

While there are many potential points of intersection between Marxism and Spinozism, three major thematic fields stand out as particularly productive. The first concerns the problem of ideology, the critique of religion, and the affective nature of the social. Marxist interpreters of Spinoza have long felt the proximity of the two projects on both methodological and political grounds. Indeed, given the importance of the critique of superstition in the TTP and its connection to the question of authority in general, both might be said to concur that “the critique of religion is the prerequisite of every critique” (Marx Reference Marx and O’Malley1994, 57; cf. Dobbs-Weinstein Reference Dobbs-Weinstein2015). Both Spinoza and Marx emphasize not only the doctrinal deficiencies, but also the material conditions and social functions of religion. Louis Althusser’s enormously influential reformulation of ideology as an “imaginary relationship of individuals to their real conditions of existence” (Althusser Reference Althusser1971, 109) might owe as much to Spinoza as it does to Marx and Lacan but it is a continuation of Spinoza’s idea that illusory self-conceptions (like superstition) are firmly rooted in and indeed lived expressions of real existential predicaments (like fear). In more recent discussions, Spinozistic theories have helped articulate the affective dimension of ideological domination. Spinoza read through Marx means highlighting the fact that the contemporary world of consumerist capitalism is not only reproduced through self-conceptions and ideas but also through affective structures and patterns of (manipulated) desire. Spinoza’s conception of the affects can be complemented with a social theory explaining how certain misconceptions and harmful psychic attachments arise in the first place, namely as effects of socio-economic division and subjection. Coexisting with the psychology, there is, as it were, a political economy of the conatus (cf. Lordon Reference Lordon2014).

The second major thematic intersection of Marxism and Spinozism concerns power, the people, and the state. While it is true that the society Spinoza had in view was not yet fully characterized by a modern class structure and its concomitant political institutions, Spinoza can be read as extremely attentive to the differential social distribution of power (cf. Balibar Reference Balibar1998). This has led to Marxist interpretations that have highlighted the complex relationship between economic and political power and have emphasized the class character of what Spinoza calls the “multitude,” which, on Marxist readings, is produced within a certain system of the division of labor and of political disenfranchisement that can only be overcome by a revolutionary action on the side of the multitude. Unleashing the power of the multitude becomes a quasi-revolutionary project of radical or “absolute democracy” (Hardt and Negri Reference Hardt and Negri2004, 307), overturning the radical asymmetry between the constitutive power of the many and the destructive managerial domination of the ruling classes. More moderate accounts of democracy have argued for the inner complexity and contradictory nature of democracy and political emancipation itself. Expanding on Spinoza’s insistence on the unpredictable nature of the multitude, they argue that even democratic politics is not immune from authoritarian seductions and will itself be traversed by multiple lines of power (cf. Balibar Reference Balibar1998; Virno Reference Virno, Bertoletti, Cascaito and Casson2004). A progressive politics of the multitude will therefore not be a linear path toward liberation from social power as such but a continual process of ever self-critical, conflictual attempts at democratization and inclusion.

A third field concerns matter and materialism. For most Marxists, as mentioned before, Spinozan materialism was a precursor to a rather determinist or even scientistic version of a doctrine explaining all natural process with the help of general laws. However, non-orthodox Marxists such as Ernst Bloch have long been aware of the rather heretic thread of materialism also running through Spinoza’s work, leading to a radical rethinking of the status of matter not as passive object but an active natural force or instance of ontological production. This is indeed resonant with many current discussions of a ‘new materialism’ and of the agency of natural entities, for which Spinoza and Marx have become recurrent references. In this context it is also worth mentioning again Althusser, one of the most influential Marxist thinkers of the twentieth century, who, in some of his last texts, had toyed with the idea of positing an undercurrent of an alternative, “aleatory materialism” in the history of Western philosophy, originating with Lucretius and leading to Heidegger and Deleuze, passing through Spinoza (cf. Althusser Reference Althusser, Matheron and Corpet2006). In this strand of thought, Althusser argues, even the seemingly strict laws of causality rest on a basis of pure contingency of bodies encountering each other in ultimately unforeseeable ways. Taking such a perspective on Spinoza and reading him against his own rationalist commitment, purges his system of many objectivist traits other interpretations hold on to and highlights the ontological dynamism it also articulates.

Marxist interpretations of Spinoza most often are characterized by a double gesture. Stressing the entanglement of the abstract ontological with the concrete historico-political elements in Spinoza’s thinking, they on the one hand argue to see his metaphysical doctrine as continuous with political and historical struggles of his day. On the other hand, they point to the deep, indeed ontological, impact of political processes. The multiple theoretical convergences between Spinoza and Marx might ultimately point to a shared overriding concern, namely the question how human beings, ever threatened by heteronomy, domination, and dependency, could liberate themselves and find some form of freedom, individual, social, and political.

Spinoza was not himself a mathematician, though he engaged in some applied mathematics (see Ep36, Ep38–41, Ep46), especially relating to his work as a lens grinder. Nevertheless, his study of mathematics left a distinct imprint on his philosophy. This is most conspicuous in the geometrical method of his Ethics, where propositions are derived from definitions and axioms à la Euclid’s Elements, but Spinoza’s works are also littered with mathematical examples and analogies, and he broaches certain questions in the philosophy of mathematics in a few of his writings (especially CM1.6, Ep12, Ep50).

It is helpful to divide the manifold ways in which mathematics bears on Spinoza’s philosophy into two general categories. In the first are the ways in which mathematical truths and structures help to model or exemplify key aspects of Spinoza’s philosophy. In the second is the question of the nature and reality of mathematical entities that Spinoza takes up in various places, and its implications for how we understand the content of his ontology.

One of the most important examples from the first category is Spinoza’s comparison of the way in which things follow from God’s nature to the way in which it follows from the nature of a triangle that its three angles equal two right angles (E1p17s). This suggests that the basic structure of Spinozistic reality – the relation between substance and its modes – is akin to the structure of geometrical objects. Spinoza also uses mathematical analogies to illustrate the nature of true ideas. In the TIE, he describes forming the concept of a sphere through the rotation of a semicircle around a center, explaining that he knows this is a true idea regardless of whether any sphere was ever formed this way (TIE[72]). Elsewhere, he suggests that humans would have remained benighted by teleology if mathematics had not revealed to them a more adequate standard of truth (E1app, ii/79–80).

Such passages indicate that mathematics models both Spinozistic reality and knowledge and is thus crucial to understanding Spinoza’s philosophy. It is little surprise, then, that Spinoza frequently uses mathematical examples to illustrate key points. However, neither mathematics’ illustrative significance, nor Spinoza’s frequent deployment of mathematical examples, entails that the sorts of mathematical objects that he uses as examples – shapes, numbers, etc. – have any existence outside the human mind. Mathematical objects may work well to illustrate certain formal or structural elements of Spinozistic reality without, however, featuring in its content.

There are a number of texts spanning Spinoza’s oeuvre in which he weighs in on the nature and reality of mathematical objects, including measure, number, unity, and shape. His verdict is consistent – such things are “beings of reason,” or what Spinoza sometimes also calls “abstractions” or “aids of imagination” (CM1.1; TIE[95]; Ep12, Ep50, Ep83). When Spinoza calls something a “being of reason” he means that it exists in the mind as a mode of thinking, but not outside the mind as a “real” thing (CM1.1). Take the case of measure. In discussing the nature of error in the Ethics, Spinoza says that the sun is more than 600 diameters of the earth away from us, although we erroneously perceive it as about 200 feet away (E2p35s). So, there is a truth regarding the sun’s distance, but what about the measurement itself? Spinoza says that measure is a being of reason used to explain or determine a continuous quantity by comparison with something else (CM1.1; Ep12). In saying that the sun is more than 600 diameters from the earth, we use the diameter of the earth as the standard of measure, and compare the sun’s distance to it. The reason this measure – 600 diameters of the earth (or any such measure: feet, light years, etc.) – is just a being of reason is easy to see: there are not in fact 600 things between earth and sun that we are counting. That is just a way of making the distance more easily imaginable. Although our judgment that the distance exceeds 600 earth-diameters is a true one (i.e., the distance would exceed 600 earths arrayed one after another to the sun), it is only in our minds that the distance is parceled into (arbitrary) units of measure. Outside of our minds, there is just the (unparceled) distance itself.

Spinoza treats number similarly. Just as measure is a being of reason used to explain or determine continuous quantity, number is a being of reason used to explain or determine discrete quantity. The precondition for numbering objects is conceiving them as members of a common genus. To use one of Spinoza’s examples, we would not think of a penny and a dollar as two unless we considered them both as pieces of money (or as members of some other common genus) (Ep50). It is in differentiating them as members of a common genus that we can number them – one piece, two pieces, etc. But why are these numbers beings of reason? Are there not in fact two things here? What Spinoza says about “unity” in the CM is instructive:

The same applies to “multiplicity” – it “adds nothing to things” (CM1.6). What I take this to mean is that though there may well be one or two things (pieces of money or what have you – it is not as though Spinoza is saying a thing or things cannot exist!), they do not exist themselves as one or two things (i.e., oneness and twoness are not properties of the things themselves). The situation is analogous to that of measure: although a distance may well be equivalent to 600 earth-diameters, it does not exist as 600 earth-diameters. Number, then, like measure, is a property of objects only in the mind that considers them that way.

Spinoza draws an important implication from his reasoning concerning number: it is inappropriate to say that God is one (CM1.6; Ep50). If God were to be numbered, he would have to be a member of a common genus, as we have seen. This would also mean that his existence would have to be externally caused, since if multiple things share the same nature (insofar as they are members of a common genus), the cause of their existence must be something other than that nature. Thus, the cause of the existence of twenty humans – not more nor fewer – for instance, cannot be human nature itself (E1p8s). But God exists through his own nature, not through an external cause, so he cannot be conceived as a member of a common genus, and, so, cannot be numbered. In the Ethics, therefore, Spinoza calls God not “one,” but “unique” (E1p14c1), though elsewhere he raises doubts about the propriety of even this appellation (CM1.6; Ep50).

Shape, too, Spinoza deems a being of reason (TIE[72, 95]; Ep50, Ep83). Here is his most extended commentary:

Elsewhere Spinoza describes a kind of being of reason used to imagine non-beings as beings, and gives “extremity or limit” as examples (CM1.1). Spinoza’s characterization of shape in Ep50 as determination, and, thus, as negation, suggests that he sees shape as a being of reason of this kind: a non-being reified only in thought.

The case of shape, however, is not so straightforward. While things can exist without having measure or number as mind-independent properties (as we have seen), and while Spinoza says that matter as a whole cannot have any shape, shape seems to add something to the being of a thing in a way that measure and number do not (recall Spinoza’s claim that number “adds nothing to things”). It is difficult to see, at any rate, what Spinoza’s conception of finite bodies might be (or how it could avoid slipping into acosmism), if they did not have one shape or another. His definition of body, moreover, as “a mode that in a certain and determinate way expresses God’s essence insofar as he is considered as an extended thing” (E2def1) appears, at the very least, to make room for shape among the real properties of bodies, given that shapes are a way of determining bodies (Ep50). But if bodies actually have shape, then shape is not just a being of reason, as Spinoza maintains (TIE[72, 95]; Ep83), but exists outside the mind as well.

A way to resolve the tension is to make a distinction between ideas of shape per se, abstracted from bodies – the sort of object the mathematician studies – and ideas of shape in rem, as the properties of bodies. The former, then, would be beings of reason, but the latter would not. This is conjectural, and controversial (cf. Melamed Reference Melamed2000 and Schliesser Reference Schliesser and Della Rocca2018), but since Spinoza does not himself tell us how to resolve the tension, it is left as a problem for interpreters.

In the Ethics, memory (memoria) is defined as a function of the association of ideas (E2p18). Almost every time I walk into my daughter’s room, I step onto a Lego piece. Thus, my idea of my daughter’s room and my idea of Lego pieces are tightly connected by association. Although there is no conceptual connection between the room and the Lego, one idea evokes the other. If a mind encounters two things, the recurrence of one will evoke the idea of the other. Explaining how ideas build a growing mental network by evoking one another, Spinoza’s understanding of memory seems to form a crucial part in his philosophy of mind.

Overall, memory is explicitly defined in only two places in Spinoza’s works. In addition to E2p18, the TIE[83] also provides a definition. The sparse treatment of memory in Spinoza’s corpus recurrently raises the question whether Spinoza really provides a theory of memory that is crucial for his system (Marrama Reference Marrama2019, 108).

How does Spinozistic memory work? If external bodies affect a human body, they leave physiological traces. Given how Spinoza conceives of the mind–body relation (see E2p7), these traces have mental counterparts in the form of ideas. Thus, when our bodies are affected, or even repeatedly affected by different things at once, the traces become stronger and likewise the ideas corresponding to them (Lin Reference Lin2005, 255–56). This way, our mind forms sequences of ideas connected by association.

Now how does memory, which forms part of the imagination, relate to the intellect? The ideas’ “connection happens according to the order of the affections of the human body” and is thus different from the “order of the intellect, by which the mind perceives things through their first causes” (E2p18s). We might say, then, that, while ideas according to the order of the intellect reflect the true causal order of things, the ideas as connected through memory represent the biographical order of things as linked to the experience of a particular individual.

Since human minds and human beings are generally seen as modes of the one substance (God) and thus are not substances in themselves, memory is arguably also central to explaining personal identity over time. What makes me the same person as yesterday and ten years ago, is not any sort of substance but my memory of my past life. As Spinoza’s example of the Spanish Poet suggests, loss of memory means loss of personal identity (E4p39s). Arguably, then, Spinoza’s account of memory anticipates Locke’s theory of personal identity as based on memory and consciousness (see Thiel Reference Thiel2011, 64–65).

Since memory consists in connections of ideas different from the order of the intellect, the precise relation between memory and intellect is itself doubtful. However, the very distinction between two orders of ideas – that is: between ideas as connected by memory and ideas in line with their true intellectual order – gives rise to Spinoza’s therapeutic project outlined in Part 5 of the Ethics. After all, a crucial endeavor lies in rearranging one’s memories “according to the order of the intellect” (E5p10; Marrama Reference Marrama2019, 141).

The Cogitata Metaphysica is an appendix to Spinoza’s 1663 DPP, his first published work and textbook on Descartes’s philosophy. The first part discusses general metaphysics, that is, being and its affections. The second part discusses special metaphysics, that is, specific kinds of being, including God and human beings. Although the work was an appendix to a Cartesian work, its structure is also a reflection of the influence of handbooks of Dutch Scholasticism by Burgersdijk and Heereboord.

Any reader of the CM must grapple with the problem of identifying which claims are properly Spinoza’s. Lodewjik Meyer’s preface to the DPP says that in both works, Spinoza “has only set out the opinions of Descartes,” although he has also “added some of his own” while retaining “many that he rejects as false” (i/131). Interpretation is further complicated by the relatively early composition date of this work, since even a remark which in fact speaks for Spinoza could reflect an immature stage of his thought. The difficulty of isolating the ‘author’ of the CM has been the subject of a 2004 volume edited by Chantal Jaquet.

The first part of CM discusses general metaphysics. Many doctrines familiar from the later Ethics are expressed here, including the contrast between mode and substance (CM1.1) and necessitarianism (CM1.3). However, CM stands out for having Spinoza’s most extended discussion of beings of reason, fictions, and chimeras. These are indeed “real beings” insofar as they are ideas, but they refer to nothing outside the mind (CM1.1). Spinoza characterizes beings of reason instrumentally – they are neither true nor false, but only “good or bad” relative to their purpose of aiding our memory and thinking.

The second part of CM turns to special metaphysics. Spinoza’s coverage of traditional topics is more uneven in a way that may express Spinoza’s own interests at the time. For example, there is an extensive discussion of God and God’s attributes in the first eleven chapters, while the twelfth and final chapter relegates angels to theology and offers a highly compressed account of the human being. Due to considerations of space I will focus on two questions about the relation between the second part of CM and the views of the mature Spinoza.

One immediate point of conflict is the theory of will. Meyer’s Preface notes that in CM2.12, both the distinction between intellect and will, and the attribution of human will to a human thinking substance, do not reflect Spinoza’s own views. However, CM presents independent puzzles in its account of divine will. In E1p17c2, Spinoza argues that God acts freely because God acts from the necessity of his nature. Although CM1.2 does claim that God acts from absolute freedom of the will, in CM2.8 Spinoza denies that God acts from the necessity of nature. This defense of divine free will may be part of a more broadly Cartesian approach to God and God’s power in CM; in a remark reminiscent of Meditation 3, Spinoza describes the human will as “produced by God at each moment” (CM1.3).

A second puzzling passage is CM2.8, which states that “Scripture teaches nothing which contradicts the natural light.” In the later TTP, Spinoza maintains that Scripture, taken metaphysically, contains a great deal which contradicts the natural light: God is strictly speaking neither a fire nor jealous (TTP7.18). However, insofar as it aims at inculcating piety, nothing in Scripture in fact contradicts the natural light, as Spinoza shows through close readings of the scriptural text. CM goes further than this later view: Spinoza seems willing to confidently assert that nothing could ever be found in Scripture to conflict with the natural light. Edwin Curley therefore calls CM2.8 an “ironic[], in my view” adoption of Maimonidean rationalism (C2:331n22). However, the context of CM makes these remarks difficult to evaluate: it’s possible that Spinoza sincerely held such a view and changed his mind, or that CM is using words like “teach” in a technical sense ultimately compatible with his mature view in the TTP.

Spinoza’s life and work are intimately connected to those of Lodewijk Meyer (Louis Meijer). Meyer and Spinoza shared an important philosophical correspondence (Ep12, Ep12a, Ep15), Meyer prepared the Preface for Spinoza’s DPP, he was among Spinoza’s friends who prepared the OP, and, according to most biographies of Spinoza, Meyer was the physician alone with him at his death. Klever identifies many important similarities in their works, rendering them sometimes almost indistinguishable; but, as Rice notes, their conclusions and style are often “radically different” (2005, 10).

Meyer was baptized into the Lutheran faith on October 18, 1629 in Amsterdam’s Old Church. By 1654, Meyer’s talents for poetry and grammar were recognized, and he was asked to edit Johan Hofman’s Dutch dictionary, Nederlandtsches Woorden-Schat, subsequently republished several times. He earned degrees in medicine and philosophy at the University of Leiden in 1660; his philosophical dissertation, On Matter and Its Affections, defends Cartesian mechanics, offers an explanation of individual bodies within a plenum universe, and argues for a physical basis for ethics. His Philosophy as the Interpreter of Holy Scripture (PSSI) was published anonymously in 1666; many believed it was Spinoza’s, and it was published in a joint volume with his TTP in 1674. It was only after Meyer’s death that friends revealed its true author.

The PSSI argues that the best approach to understand sacred texts is to come to them without preconceived opinions and that philosophy (especially the Cartesian method) is the sole and best judge when it comes to making sense of their meaning. Spinoza in the TTP, on the other hand, asserts that Scripture should be interpreted through itself alone and not from the sort of knowledge that derives from the natural light of reason; nor, contra Maimonides, is the truth of Scripture to be tied to how well it accords with reason. Meyer’s claim is that reason alone may assist theology to develop sound doctrine for faith and morality (PSSI 24) and perhaps even to help reunite the splintered churches (PSSI 240–41). This work was roundly condemned by several ecclesiastical authorities.

In 1669 Meyer co-founded the art academy Nil Volentibus Arduum (“Nothing is impossible for the willing”), whose purpose was to promote literature and the arts. Meyer contributed many essays, translations, and other projects to its work.

Whether Meyer influenced Spinoza or Spinoza influenced him may be up to debate, but Klever and others note that with their regular exchange of thoughts and drafts on similar themes and ventures, it is not surprising that some phrasings and definitions are remarkably similar. Of their surviving correspondence, all dated 1663, Ep12 from Spinoza to Meyer, known as “The Letter on Infinity,” was copied and widely circulated among friends and colleagues; this letter is very useful for its plain discussion of Spinoza’s concepts of “substance,” “mode,” “eternity,” and “duration.” Ep12a and Ep15 deal with Meyer’s preparation for the upcoming publication of the DPP. In his preface for that work, which echoes some of the wording found in parts of PSSI, Meyer is careful to underline Spinoza’s requests to announce that the work does not present Spinoza’s views and that parts were composed in under two weeks.

Spinoza’s concept of mind (mens), including his views about the human mind, is among the most controversial issues of his philosophy; it has prompted many debates, in particular concerning the status of finite minds. That Spinoza might have a problem in this regard was a worry already voiced by Pierre Bayle in his Dictionnaire historique et critique; but the same concern was present in the Pantheism Controversy between Moses Mendelssohn and Friedrich Jacobi, and questions about the status and individuation of the human mind were also driving the readings of Spinoza developed in German Idealism. Critics in particular voiced the concern that Spinozism cannot account for the numerical difference between finite subjects and thus offers no solution to the problem of the individuation of minds. At first glance, it is indeed a peculiarity of Spinoza’s approach that it seems to lack a solution. Assume, as a somewhat simplified picture of Spinozism suggests, that all minds are merely modifications or modes of divine thought. Assume furthermore that two minds of two different people are thinking about the very same object, for instance, they admire the same flower growing in front of the window. How, then, can we explain that they are two distinct minds, rather than simply one? Arguably, Spinoza has the means to address this problem, but to understand Spinoza’s concept of the human mind requires, in any case, that we see how it tackles the problem.

The problem arises because Spinoza departs from the ordinary scheme of thought. Usually, we consider numerical differences between people’s minds as given: it is natural to think of me as a distinct entity from you and it is equally natural to think that your mind is numerically different from mine, however alike our thoughts or mental states may be. Underlying this way of thinking is a conceptual presupposition that minds are categorically distinct from their states, thus we may share some thought p without ever wondering whether we also share a mind. Traditionally, this distinction has often been spelled out in terms of a contrast between ‘substance’ and its ‘modes’ or ‘accidents.’ In this framework, minds are described as substances having or bearing particular states, which means that minds differ from each other simply by being distinct bearers of thoughts. Notably, both Aristotelian and Cartesian conceptions of minds rely on the notion that either the whole person or the mind is a substance.

Not so for Spinoza. In the Ethics, he explicitly rejects the assumption that minds or people are substances. In E2p10, he explicitly denies that the “being [esse] of substance … pertains to the essence of man” or that “substance … constitutes the form of man.” In positive terms, this means that “the essence of man is constituted by certain modifications of God’s attributes” (E2p10) and this is the case for both mind and body. This conceptual framework is also present in the subsequent propositions in which Spinoza elaborates on his concept of mind in some detail.

Spinoza begins by saying in quite general terms what the human mind consists of, before he continues by specifying a couple of conceptual implications: “The first thing that constitutes the actual being of a human mind,” he claims in E2p11, “is nothing but the idea of a singular thing which actually exists.” In Spinoza research, this is often read as the claim that the human mind is an idea God has of a particular singular thing, viz. the particular human body that the mind is related to. Indeed, following E2p7s, there exists for any mode of Extension a corresponding or identical mode of Thought, which it also represents (ii/90). Reading the argument in this manner, many scholars assume that in E2p11 Spinoza just applies this general ontological structure to the essence of the human mind. However, there are two textual reasons why one may refrain from understanding E2p11 in this vein. First, there is no reference at all to E2p7 or E2p7s, and this neither in E2p11 itself nor in any of the following propositions. Second, strikingly, a closer look at the original text suggests a wording slightly different from the one quoted above. In Latin, E2p11 says: “Primum, quod actuale mentis humanae esse constituit, nihil aliud est, quam idea rei alicujus singularis actu existentis.” This proposition indicates that for Spinoza a mind is nothing over and above some idea. The interpretive challenge, however, is to decide what sort of idea Spinoza had in mind here. The usage of the word aliqui, meaning “some,” “any,” or “whichever,” suggests that he did not want to specify the thing the idea constituting the human mind is about. Taking this seriously, one may read E2p11 as not putting forward the metaphysical claim that the mind consists in the idea (meaning: God’s idea) of the specific singular thing (meaning: the body) which this idea/mind is about, but instead as explicating a semantic condition for meaningful talk of human minds to the effect that only entities having ideas of actually existing singular things can be said to have a mind or to be minded subjects.

This being said, it is nonetheless a major claim of Spinoza’s that the human mind is the idea of the human body. It is established in E2p13, which reads: “The object of the idea constituting the human mind is the body, or a certain mode of Extension which actually exists, and nothing else.” Unlike in E2p11, Spinoza uses here the Latin adjective certus, “certain,” which arguably indicates that E2p13 addresses a different problem than the earlier proposition. On one interpretation, at stake in E2p13 is the issue of the individuation of minds, which is a vital concern for him, given that he denies in E2p10c that human beings are substances, and given that, as he pointed out in E2p11, being or having a mind is a matter of one’s having ideas of actually existing singular things. The latter claim is a problem, because it is often the case that people share ideas of actually existing things. If a group of people at a party look at the moon, they can be said to share the idea of the moon. The question then is, why we should think that there are fifty minds rather than just one mind. Spinoza’s answer would be that, while looking at the moon, each of these people’s minds is at the same time also representing a particular, distinct object: the body it is identical with.

Thus, as in the Aristotelian tradition, the body serves as a principle of individuation. Yet, on Spinoza’s approach, it does so for different reasons. The body serves as a principle of individuation not because it is united with the human mind, but because it is the object of the idea constituting the mind. But this raises a further question. If I am in a group of fifty people watching an eclipse of the moon, and in front of me is a tall man preventing me from actually seeing it, then my mind’s focus is most likely not on the moon, nor on my body, but on the body of the tall man in front of me. So, the object of the idea I am mostly concerned with at this moment is the tall man’s body, and it is not my own, but the tall man’s body that is the main object of my mental life at this moment. One might be tempted to say that, strictly speaking, if my mind is about the tall man’s body at this moment and if his mind is concerned with the same body, there is (temporal) overlap of our minds. In that case, Spinoza would definitely have a problem with the individuation of minds.

But this option of overlapping minds is definitely ruled out in the demonstration to E2p13. Crucially, E2p7s is again not mentioned here, and it is generally not parallelism that does the argumentative work here. Instead, Spinoza presents a reductio ad absurdum that makes use of several axioms of Part 2, which arguably express a couple of phenomenological facts. A key role is played by E2a4 which gives voice to the experience that “We feel that a certain body is affected in many ways.” Although this axiom doesn’t speak of one’s own body, the evidence of one’s being acquainted with one’s own body whenever the latter is affected is just what Spinoza invokes here: there is a difference between the way in which we are familiar with our own body in contrast to the way in which we know of other bodies and their affections. Therefore, minds which are united through this kind of direct phenomenological acquaintance with different bodies are also numerically distinct and the scenario of an overlap of minds is absurd (cf. also E2p13d, ii/96).

This arguably suggests also how Spinoza would have responded to the objection of having advocated pantheism, a position with which his philosophy has often been compared since the early eighteenth century. The term ‘pantheism’ didn’t exist at his time, but there was a precursor of this label in medieval and late Scholastic debates, namely Averroism, a term that was used to denounce opponents as heretics. Philosophically, both positions can be considered as forms of monopsychism: they assume that there is only one singular subject or intellect with which each finite subject, either as such or when acquiring intellectual understanding, is united. It is likely that Spinoza was charged with Averroism in conversations during his lifetime. In E2p11cs, he even seems to allude to this objection, although without naming it, when he writes:

Whether it was really Averroism that Spinoza had in mind here is of course an open question. But it is legitimate to surmise that in developing his concept of mind, he was already responding to the concern as to how, in a framework that does not consider minds or people as substances, monopsychism can be avoided.

The same tendency also drives Spinoza’s use of the notion of “intellect” in the Ethics (in contrast to the way in which this term shows up in his early TIE, where it is used to describe the mind of the reflecting subject). Apart from its utilization in certain definitions (e.g., E1def4: “By attribute I understand, what the intellect perceives of a substance, as constituting its essence”), the term “intellect” shows up in connection with the notion of an infinite intellect, which is introduced by way of clarifying the idea of divine necessity in E1p16: “From the necessity of the divine nature there must follow infinitely many things in infinitely many modes (i.e., everything which can fall under an infinite intellect).” The infinite intellect is not defined here in terms of a special cognitive capacity attributable to a divine subject; instead, it serves as an ideal term that invokes the notion of complete representation of the universe as one would get if one looked at it from a divine point of view. Being marked by completeness, this notion comprises whatever divine necessity entails. This view is later corroborated in E1p31d, where Spinoza explicitly says that by “intellect” he understands “not absolute thought, but only a certain mode of thinking.” In E1p31s he further clarifies that in talking of an “actual intellect,” he does not use this term in the manner it was used in the Scholastic debate about Aristotle’s De anima, but seeks “to speak only of what we perceive as clearly as possible, i.e., of the intellection itself.” That is, the term “intellect” is used to denote instances of knowledge that are qualified as intellectual mode – in the non-terminological sense of “mode” – or manner of thinking, and it is thus not to invoke the assumption of there actually being a divine intellect. Arguably, moreover, given that the feature Spinoza has in mind here is a “mode” or “manner” of thinking and not an epistemic subject, nor a capacity attributed to a particular epistemic subject, these instances of knowledge referred to as “infinite intellection” are such that humans too may have them.

Now, there are statements in the Ethics in which Averroistic notions seem to resonate most strongly. In E2p11c, for example, Spinoza concludes from the previous proposition, according to which the human mind is constituted by ideas of actually existing singular things, that the human mind is “part of the infinite intellect of God.” This proposition has often been read as contending that the human mind consists in an idea had by God, to the effect that it is God who has the idea constituting the human mind, as well as all other ideas that are in that human mind. But alternative readings are available here. Assuming that Spinoza, as indicated by E1p31s, employs the notion of infinite or divine intellect as an equivalent for perfect human cognition, E2p11c can also be read as a further clarification of this notion, by introducing the distinction between partial and complete understanding of the essence of some object, that is, between what Spinoza also calls “adequate” and “inadequate” knowledge.

Spinoza’s concept of the human mind has major implications for his practical philosophy. Many of the moral theoretical doctrines Spinoza voices in Parts 4 and 5 of the Ethics as well as in his political writings would be inconceivable otherwise than on the basis of his concept of the human mind. His key insight is this: if the mind is not a substance, but constituted by the ideas we have of things – including, of course, our own body – then the mind is by its very definition subject to change over time. The constitution of the human mind, in other words, is such that it allows for quite radical changes. Moreover, since it is the particular ideas we have that make our mind such-and-such, it is our mind and not just short-term mental conditions that is modified by our own mental activities. The question arises as to how we can make use of this insight for our own good. Spinoza’s main point in addressing this question is to emphasize the value of knowledge, that is, in his terminology, of adequate ideas. Concretely, goodness of knowledge comes in two varieties: first, knowledge is instrumentally good, insofar as knowing with certainty what is useful for us makes success in leading a good life more likely; second, knowledge is good with respect to the constitution of one’s own mind, since if we succeed in replacing our imaginative ideas with an adequate understanding of the nature of things, we come to have a more constant mind, one that consists in a set of stable mental dispositions. This, in turn, is good because it allows for rational guidance; whereas if, by contrast, our mental states were permanently fluctuating, we could not develop a reliable form of mental agency. What makes Spinoza’s ethical outlook special, finally, is that this understanding of the constitution of minds makes room for the notion of a mind’s achieving perfection through knowledge. Spinoza describes this in terms of the mind’s becoming an “eternal” entity. To be sure, this is only an ideal that marks a perfection we (most likely) never reach, but this ideal is nonetheless a meaningful concept. Assume that we can modify our minds step by step by substituting, for our imaginative ideas, adequate and eternally true ideas, with the effect that our mind comes closer to the point where it is constituted entirely by ideas that are necessarily true. Perfection is reached when the mind knows all its ideas to be necessarily true and no longer doubts them. Thus eternity entails insight, which means that this excellent constitution of the mind is also accessible from a subjective viewpoint. We can “feel and experience that we are eternal,” Spinoza famously writes in E5p23s (ii/296).

Other ways of making use of his notion of mind and the possibilities of mental change are also discussed in Spinoza’s political philosophy and his concept of personal freedom. Overcoming bondage, for example, is largely a matter of acquiring a mind that is grounded in adequate ideas rather than in fiction or false identification. Yet, being free is not the same as having an eternal mind. Rather, Spinoza invokes the notion of a “free man” to describe an ideal individual who survives and is happy in a non-ideal environment. The “free man” is cautious and wise, but in the first place he is an individual mind that displays its judgment freely, if not in speech, then in evaluation of what is good for him. The free man is an individualist who keeps himself safe from the passions of others. This said, he would also not deny his dependency on others with respect to his physical survival and social flourishing, but he would make sure that he does not compromise himself by getting involved with passions. This individualist tendency of Spinoza’s views about the free man is also maintained in his political theory with a communitarian understanding of the power of political bodies. Yet, this communitarian view does not override the mind’s constitutive individuality. People may agree on many things and build a community on the basis of such agreement, or they may be persuaded or manipulated into conformism, but their minds do not, literally speaking, become one single mind, although they may be considered as if they were one mind (ii/223, iii/284–85, iv/77). Therefore, what each mind “embraces as true and rejects as false” is “subject to each individual’s control [jus]. No one can surrender that [right], even if he wants to” (iii/239/16–18).

To conclude, we can say that despite the revisionary metaphysical conception of the mind, which allows for essential changes in the constitution of people’s minds, despite the communitarian understanding of power developed in the political writings, and despite pantheist interpretations which suggest that the individual’s mind is an idea in the divine intellect, Spinoza retains the notion that as minds or minded beings we are individuals and irreducibly so.

According to Spinoza, the mind and the body are “one and the same thing but expressed in two ways” (E2p7s). A natural interpretation of this doctrine is that the mind and body are numerically identical: there is a single mode of God that is expressed both under the attribute of Thought as mind and under the attribute of Extension as body. This is an important doctrine for Spinoza. He uses it to directly argue (1) for the parallelism doctrine (which says that the causal order exemplified by the various attributes is the same) (E2p7s), (2) that the mind represents everything that happens in the body (E2p12), (3) that ideas of non-existent things are in God’s infinite idea in the same way as the formal essences of things are in God’s other attributes (E2p8), and (4) that the idea of the mind is identical to the mind itself (E2p21). Furthermore, by means of these doctrines, Spinoza derives further important consequences for his philosophy of mind, action, and ethics. Thus, Spinoza’s mind–body identity thesis is crucially important to almost every part of his philosophical system.

What are Spinoza’s reasons for holding that the mind and the body are identical? He says:

In other words, all the attributes belong to a single substance and hence the thinking substance and the extended substance are one and the same substance. From this Spinoza concludes that the mind and the body are one and the same thing, expressed in two different ways.

Thus stated, it is unclear why Spinoza thinks that mind–body identity follows from the fact that there is only one substance. After all, there is nothing incoherent in the idea that the modes of a given attribute of a multi-attribute substance are numerically distinct from the modes of another attribute of the same substance. Indeed, to claim otherwise might appear to verge on nonsense, depending on exactly how the attributes are understood. For example, according to one common understanding of the attributes in post-Cartesian philosophy, they are essential determinable properties of a substance, the modes of which are their determinates. On such an understanding, the idea that modes of distinct attributes are identical might appear as absurd as saying that there is a determinate color that is identical to some determinate size.

In order to make Spinoza’s thinking on this topic explicit, it will be necessary to say something about how Spinoza understands the attributes and their relation to substance. A full account of Spinoza’s theory of the attributes lies outside the scope of this entry, but, on one interpretation of it, an attribute is the essence of a substance (see E1def4). This essence, however, can be conceived of infinitely many ways and these different ways of thinking about it create a conceptual distinction – i.e., a distinction of reason – between different attributes. That is, each attribute is the essence of the substance conceived under a separate conceptual guise. These guises resemble conceptual languages that are distinct from each other despite possessing equivalent expressive powers. They present the same content to the intellect but, as Spinoza emphasizes in E1p10, they are such that the concepts associated with them bear no inferential relations to one another. Thus, Thought is just the essence of God or nature insofar as we think about it using one conceptual language, and Extension is just that same essence insofar as we think about it using a different conceptual language (Lin Reference Lin2019b).

Given that there is only one substance with a single essence, the modes that are comprehended under different attributes are, in themselves, one and the same thing. There is no genuine metaphysical distinction between them. There is, however, a distinction of reason between them. Just as the various ways the essence of substance is presented to the intellect creates a distinction of reason between, for example, Thought and Extension, so too the way its modes are presented to the intellect introduces a distinction of reason between the mind and the body.

The first important application of this mind–body identity theory in Spinoza’s Ethics is the derivation of the version of the parallelism doctrine found in E2p7s. According to the parallelism doctrine, for each idea there is a body which it represents and for each body there is an idea that represents it. Moreover, a causal relation obtains between two bodies just in case a causal relation obtains between the ideas that represent those bodies. That is to say that the causal orders of Thought and Extension are isomorphic. Although Spinoza had previously attempted to demonstrate this doctrine in E2p7d, that argument is generally regarded as failing to fully support it because it does not rule out the possibility that the attribute of Thought has richer causal structure than the attribute of Extension (Della Rocca Reference Della Rocca1996b). Fortunately for Spinoza, however, the argument that he gives in E2p7s premised on mind–body identity is arguably more successful. If the mind and the body are identical, it follows from Leibniz’s Law – the uncontroversial logical principle that if x is identical to y, then everything true of x is true of y and vice versa – that the mind occupies a particular causal role just in case its body occupies that same role. Thus, the isomorphism between the causal orders of Thought and Extension is secured.

Spinoza also uses his mind–body identity theory to argue for what might be called corporeal omniscience: there is an idea in the mind of everything that happens in the body (E2p12). The mind is the idea identical to the human body. Because every mode of Extension is identical to a mode of Thought, every part of the body will be identical to an idea. Spinoza concludes that if my body participates in some event, then, because of the identity of mind and body, the mind represents that event.

But Spinoza’s argument appears to only show that for everything that happens in the human body, there is an idea to which it is identical. What entitles him to the further conclusion that such ideas represent the bodies to which they are identical? Part of the answer is that Spinoza appears to believe that a mode of Thought is the idea of a mode of Extension just in case it is identical to that mode of Extension. But why should he believe that? This is a difficult and controversial question. That said, an explanation consistent with the account of the attributes given earlier is that representation is nothing metaphysical over and above identity. What needs to be added to identity to get representation is merely to conceive of something under the attribute of thought. In other words, to say that x represents y is just to say that x is identical to y and x is presented to the intellect under the attribute of thought. (For a different perspective, see Hübner Reference Hübner2022b.)

A further application of the identity theory is found in E2p8 where Spinoza argues that “ideas of singular things, or of modes, that do not exist must be comprehended in God’s infinite idea in the same way as the formal essences of the singular things, or modes, are contained in God’s attributes.” What does this strange claim mean? Spinoza’s topic here is whether ideas can exist independently of the objects that they represent. His answer is that they cannot because the idea of a thing and that thing are identical. In the case of mind–body identity, this has important ramifications for traditional views such as the immortality of the soul. According to Spinoza, the mind is the idea of the body to which it is identical (E2p13). This entails that if the body ceases to exist, the mind too ceases to exist. Thus, the mind or soul is not immortal, at least in the traditional sense of being something that perceives things or remembers past events (E5p21).

But how is it, then, that we are capable of thinking about non-existent objects? Spinoza says that, for example, every physical thing that doesn’t exist but is such that we can think about it, has a formal (but not actual) essence entailed by the attribute of Extension. From the fact that we have an adequate idea of the eternal and infinite essence of God, we can infer the formal essences of things (E2p40s2). This formal essence is what we are thinking about when we think about non-existent things. And because ideas and their objects are identical, ideas of formal essences are identical to those essences. Moreover, because they follow from the absolute nature of God, these essences are infinite and eternal (E1p21). For this reason, although the soul is not immortal, there is a part of our mind that is eternal (E5p23): what remains of my mind when my body is destroyed is the idea of my body’s formal essence (which also remains).

Finally, Spinoza generalizes his identity theory to argue that the idea of the mind is related to the mind in the same way that the mind is related to the body: they are identical (E2p21). Every idea is identical to the object it represents. The mind represents the body and, hence, they are identical. Furthermore, the idea of the mind represents the mind itself, and, by the same token, they are identical. But whereas there is a distinction of reason between mind and body because they are conceived under different attributes, the idea of the mind and the mind itself are conceived under the same attribute. Wherein, then, lies the difference between them? Spinoza’s answer is that there is a distinction of reason between them insofar as the idea of the mind is the same idea as the mind itself, but whereas the mind is conceived of in relation to its object, the idea of the mind is that same idea considered without relation to its object (see E2p21s).

Although numerical identity of mind and body is a natural interpretation of Spinoza’s claim that they are “one and the same thing but expressed in two different ways,” it appears to sit uneasily with some of Spinoza’s other doctrines. Someone might wonder, for example, how a single mode could inhere in two distinct attributes?

The notion of an attribute is a technical notion in the Cartesian metaphysics that clearly exerts a great influence on Spinoza’s own metaphysical thinking. For Descartes, every mode of a “simple substance” entails one and only one “principal attribute” possessed by that substance (Principles of Philosophy i.53). For example, size and shape are modes that entail that any substance in which they inhere has the attribute of Extension and entail that it doesn’t have any other attribute. Likewise, willing and imagining are modes that entail that any substance in which they inhere has the attribute of Thought and entail that it doesn’t have any other attribute. This aspect of Descartes’s conception of the relationship between modes and attributes appears to be respected by Spinoza’s own metaphysics. For example, he says that “The formal being of ideas is a mode of thinking … a mode that expresses, in a certain way, God’s nature insofar as he is a thinking thing. And so … it implies the concept of no other attribute of God” (E2p5d). In other words, an idea, as a mode of thought, implies the attribute of Thought and no other attribute, which hews closely to Cartesian doctrine on this matter. But if a single mode could be a mode of two attributes – for example, Thought and Extension – then that mode, expressed both as mind and body, would imply both that God is thinking and that he is extended, which appears to contradict what he says in E2p5d. For such reasons, it might be concluded that the mind and body cannot be numerically identical.

This difficulty can, however, be solved without giving up the numerical identity of mind and body by adopting a suitable interpretation of the attributes. On the interpretation of the attributes introduced earlier in this entry, all of the attributes are identical to God’s essence and differ from each other only insofar as they are conceived of in different ways. Each of these different ways is associated with a unique family of concepts or conceptual language the concepts of which bear no inferential connections to the concepts of any other conceptual language. These different conceptual languages both fully and completely express the same content (viz., God’s essence and the things that follow from it); they differ only in manner of expression. This solves the Cartesian problem of how modes of different attributes can be identical to each other. If we conceive of a mode under the attribute of Extension, then we are not in a position to infer that its subject of inherence is thinking. But neither are we entitled to conclude that it is not thinking.

Another serious problem is that Spinoza appears to deny mind–body causation. This is because he appears to think both that each attribute is conceived through itself and that if something causes an effect, then the effect is conceived through the cause. But if, for example, a mental cause were to produce a corporeal effect, then a corporeal effect would have to be conceived through a mental cause. Spinoza, however, clearly thinks that the fact that each attribute is conceived through itself rules out the possibility that something corporeal (i.e., a mode of the attribute of Extension) can be conceived through something mental (i.e., a mode of the attribute of Thought).

And yet such a denial of mind–body causation would look to conflict with mind–body identity. If a mind causes another mind to think, and every mind is identical to a body, then, it would seem, a body causes a mind to think. Similarly, if there is a body that causes another body to move, and each body is identical to some mind, then, to all appearances, a mind causes a body to move. Such conclusions, however, seem to plainly violate Spinoza’s apparent ban on mind–body causation.

Commentators have adopted various strategies for dealing with this apparent conflict between mind–body identity and Spinoza’s seeming rejection of mind–body causation. Although a full discussion of these strategies falls outside the scope of this entry, it will still be worthwhile to briefly summarize some of the more prominent ones. For example, some have seen this conflict as indicating that Spinoza could not have meant his claim that the mind and body are “one and the same thing” to express literal numerical identity of mind and body (Marshall Reference Marshall2009). Others have argued that Spinoza sees causation as an intentional property – a property such that co-referential expressions cannot be substituted in the contexts that we use to ascribe such properties salva veritate (Della Rocca Reference Della Rocca1996b). Still others have claimed that Spinoza does not accept the Indiscernibility of Identicals (D. Garrett Reference Garrett and Melamed2017; Morrison Reference Morrison and Melamed2017; Hübner Reference Hübner2022b). And some have argued that Spinoza’s apparent ban on mind–body causation is best understood as a ban on mind–body causal explanation (Koistinen Reference Koistinen1996; Lin Reference Lin2019b).

Theories of religion, prophecy, and the interpretation of Scripture in the TTP incorporate Spinoza’s account of miracles (miraculi). “On Miracles,” Chapter 6 of the TTP, includes two different senses of the term. The chapter opens with an acknowledgment of an ordinary understanding of the term, on which a miracle is a divine action in which God violates the universal laws of nature (TTP6.3–4). Spinoza strongly denies that there are any such actions. He does, however, offer a different sense of “miracle,” which he accepts:

Spinoza’s argument that there are no miracles in the first sense of the term depends upon his rejection of what he takes to be the ordinary understanding of divine action, on which God does not act so long as nature acts in an ordinary way (TTP6.2). Instead, Spinoza maintains, nature’s virtue and power just are God’s virtue and power; to hold that a given divine action is an action against nature, then, would be to hold “at the same time also that God acts in a way contrary to his own nature. Nothing would be more absurd than that” (TTP6.9). While many doctrines of the TTP may be in tension with the doctrines of the Ethics, this view seems to be consistent with the account of God in Ethics 1 and the criticism of ordinary views of God in the Appendix there (see especially ii/81/15–19).

This dismissal of miracles provoked a great deal of angry response from early readers of the TTP – it is evident, for example, in letters to Spinoza from Albert Burgh and Nicolas Steno – and was a major source of the book’s notoriety (see Israel Reference Israel2001, chap. 12; and Nadler Reference Nadler2011). For an assessment of its strength, it may be useful to compare the TTP6 doctrine to David Hume’s well-known criticisms of miracles. (See, for example, Enquiry Concerning Human Understanding, Section x). Spinoza’s doctrine seems stronger inasmuch as, in taking the view that there is a miracle to be the height of absurdity, he rejects the possibility of a miracle, whereas Hume appears to maintain merely that miracles could not be known.

It is the second, less remarked sense of “miracle,” however, that offers a better indication of central themes of the TTP. Such ideas – ideas that, in a given mind, do not relate to other things – characterize the minds of prophets, on Spinoza’s account of them in TTP2. It is also the purpose of Scripture to evoke these ideas in the minds of ordinary people:

Finally, the idea of God in the second tenet of universal faith may be a miracle in this sense. In order to be faithful, it suggests, a person must believe that God is unique because without such a belief, one cannot wonder at or be devoted to God (TTP14.25). Collectively, these doctrines make ideas of what is unique in experience the starting point for religion in the same way that the common notions, ideas of what is present always in experience, are the starting point for reason (E2p38–40).

The Ethics includes an account of such ideas, which affirms their relation to wonder, devotion, and, therefore, to miracles. Spinoza argues at E3p52 that the idea of a thing that we have not seen together with other things and that does not resemble other things in our experience will persist in the imagination. The demonstration draws upon his doctrine of the association of ideas (E2p18,s); it suggests that the ordinary psychological mechanisms that move the mind from the contemplation of one thing to the contemplation of another will not apply in the experience of a unique thing (cf. Descartes’s Passions of the Soul, art. 53). In such an experience, then, the imagination will persist. This is, on Spinoza’s account, the experience of wonder, which he introduces in a scholium to the proposition: “This affection of the Mind, or this imagination of a singular thing, insofar as it is alone in the Mind, is called ‘wonder [admiratio]’” (E3p52s). Note that the relevant Latin terms, miraculum and admiratio, are closely related, both deriving from the verb miror, which means “to marvel at” or “to wonder.” Thus, an English writer might similarly argue that human minds find wonders wondrous. Definitions of passions associated with wonder, notably “devotion,” follow in the scholium.

On Spinoza’s account, the purpose of the state, in the first instance, is to bring all people to behave as if they were fully rational. From reason, we always cooperate and are aids to one another, and it is only in behaviors motivated by passion that we can diverge and conflict (E2p37s2; cf. TTP1). All of us, however, are vulnerable to passions and many of us are highly passionate. Written law and a motivating force to obey it, then, are necessary for our security and welfare. Because ideas of the unique are so persistent, associated passions are strong motives. Religion based in ideas of miracles promises, then, a motive from which the highly passionate, and all citizens insofar as they are passionate, can cooperate. If we cannot cooperate, help one another, and act justly from the motive of reason, we can do so from wonder and the sort of love, devotion, that is associated with it. Other powerful passions, such as the fear that the threat of punishment inspires, might motivate obedience to some degree. Indeed, Spinoza emphasizes fear in this context, especially in the Ethics (E2p37s2, E4p54s but see also TTP4.6 and TP3.3, 6, and 8). Spinoza suggests in the TTP, however, that devotion is a superior motive. Consider, for example, a soldier that we ask to risk her life for our nation. She might not do so from fear, if the fear that the opposing army inspires is greater. If she is motivated by devotion to the state, however, she may still fight for us. Similar reasoning, Spinoza argues, led Moses to introduce religion among the Hebrews (TTP5.29).

The purpose of the state, beyond the initial project of bringing people to act as though they are rational, is ultimately, on Spinoza’s account, to help people to become more rational (E4p54s, TTP20.12). A central puzzle that the emphasis on miracles as a social motive in the TTP presents, then, relates to this purpose. Miracles in the first sense do not exist, and it would be absurd, Spinoza writes, to maintain that they do. If—as accounts of prophecy, Scripture, and miracles in the TTP suggest—the belief in miracles serves as a primary motive for social behavior, then, that motive is also highly irrational. It may not be clear on the account of the TTP how a good state can help its citizens to become rational without undermining those ideas – ideas of miracles – that are essential to cooperation.

The necessity (necessitas) of all things is one of the most distinctive features of Spinoza’s philosophy. For those opposed to Spinoza it is, along with the treatment of God, its most notorious feature. In the Ethics, it is proclaimed and explained in various places. One main point is that God, the only substance, exists necessarily (E1p7d, E1p11). A second main point is that nothing exists apart from God and what is, is conceived through God (E1p14–15), but what is conceived through God “follows [sequi]” from God: “From the necessity of the divine nature there must follow infinitely many things in infinitely many modes, (i.e., everything which can fall under an infinite intellect)” (E1p16). In this passage, the scope of the “everything” characterizing what falls under the infinite intellect seems to be everything without qualification, leaving no room for anything to not follow from God. Moreover, God is the cause of everything (E1p16c1), and E1a3 tells us, “From a given determinate cause the effect follows necessarily; and conversely, if there is no determinate cause, it is impossible for an effect to follow” (emphasis added).

Spinoza’s commitment to the necessity of all things comes with a complementary commitment regarding metaphysical, genuine “contingency” or “possibility” of things. Spinoza states in E1p29 that, “In nature there is nothing contingent [contingens], but all things have been determined from the necessity of the divine nature to exist and produce an effect in a certain way.” The point is reinforced in E2p44: “It is the nature of reason to regard things as necessary, not as contingent.” That rules out our using reason to conclude that there are genuinely contingent things. When humans take something to be contingent or possible, that is a matter of epistemology, rather than metaphysical insight into the nature of things. Considering things to be possible or contingent comes from ignorance, resulting from either carelessness or not getting the right handle on the infinite complexity and interconnection of finite things.

In E1p33s1 Spinoza writes:

This point is revisited at the end of this article.

Spinoza is clear that everything is necessary, but scholars have questioned what exactly Spinoza means by calling something “necessary.” It has been proposed that Spinoza might have recognized, or did in fact recognize, different kinds of necessity applying to different kinds of things (see for example Curley and Walski Reference Curley, Walski, Gennaro and Huenemann1999). If there are different kinds or grades of necessity, it could then be argued that some lower grades of necessity correspond to non-epistemic grades of contingency. And if Spinoza’s system allows for some sort of metaphysical contingency, that would be some reason to say that Spinoza is not a “necessitarian” tout court.

A good first step to an interpretation of Spinoza’s position on necessity begins with the sense, mentioned above, in which God necessarily exists. God cannot be conceived as not existing because an adequate conception of God includes God’s necessary existence (E1a7). The essences of Spinoza’s individual, impermanent, finite things do not include existence (E2a1). For that reason, we might wish to say that the necessity applying to God’s existence is not the same as whatever necessity applies to the existence of finite things. Spinoza puts the distinction in terms of a thing being necessary by reason of its essence as opposed to a thing being necessary by reason of its cause (E1p33s1). However, Spinoza himself chooses not to term finite things “contingent” in a metaphysical sense even though existence is not included in their essences (see E1p24 for instance). The kind of necessity applying to finite things, if indeed it is distinguished from other kinds of necessity, depends on how finite things are related to the necessity of infinite things.

Another complication for understanding Spinoza’s views about modality therefore arises from a general consideration of how one thing “follows” from another in Spinoza’s philosophy. Much will depend on how Spinoza understood the relation of “following.” In recent philosophy, the relation is generally taken to hold among propositions or truths, such that established systems of formal logic characterize the relation. Exactly what a proposition is has been a matter of dispute, but some scholars have proposed that recent logical calculi might illuminate Spinoza’s views on necessity (Curley Reference Curley1969, Bennett Reference Bennett1984). Spinoza himself, however, has the “follow from” relation holding among the denizens of his universe – not propositions or truths used to describe these denizens (Hübner Reference Hübner and Melamed2015c, Nelson Reference Nelson and Kaufman2017, Shein Reference Shein2020). Everything accordingly follows from, and is conceived through, God (E1p15–16), but some things follow immediately from God’s unmodified, absolutely infinite attributes (E1p21). These are what scholars have termed the ‘immediate infinite modes.’ Other things, the so-called ‘mediate infinite modes,’ follow from other infinite modes (E1p22). Finite things, in contrast, do not follow from God’s unmodified attributes, that is, from God “considered absolutely.” They follow instead from the divine nature “insofar as it is considered to be determined to act in a certain way (by [1]p28)” (E1p29d). In other words, they follow from God considered as modified. Spinoza specifies in the Ethics that the immediate infinite modes are necessary and eternal because they follow from God’s attributes taken absolutely. And mediate infinite modes are necessary and eternal because they follow from other necessary and eternal infinite modes. In E1p23d Spinoza demonstrates this directly from first principles, but some scholars have noted that it conforms to a standard principle in modal logic: propositions that follow from necessary propositions are themselves necessary (e.g., Bennett Reference Bennett1984). Infinite modes could be called consequently necessary to mark that Spinoza gives reasons for regarding them as necessary that are different from the reasons for God’s existence being necessary. If Spinoza’s “following from” relation is not strictly transitive, one could even distinguish the necessities applying to infinite modes that are immediately consequently necessary from those that are mediately consequently necessary.

Commentators who do not think that Spinoza is a necessitarian tout court, however, have focused on the kind of necessity applying to finite things. According to E1p28, no finite thing can exist unless it is “determined to exist and produce an effect by another cause which is also finite.” So even though the entire infinite system of finite things ultimately follows from the absolute nature of God, the existence of any individual finite thing considered in isolation does not directly follow from the absolute nature of God alone. For an individual mode considered in isolation to follow from God, Spinoza additionally requires “an attribute of God insofar as it is modified by a modification which is finite and has a determinate existence” (E1p28d). In light of this it might be said that the necessity applying to individual finite things is different from the necessity applying to infinite modes, which do follow immediately or mediately from the absolute nature of God. On this interpretation, the necessity of an isolated finite mode is not an “absolute” necessity, but instead a necessity “relative” to other finite modes that determine it.

In light of the sense in which finite modes can be considered relatively, but not absolutely, necessary, some scholars have proposed that Spinoza would admit other possible worlds (Curley Reference Curley1969, Bennett Reference Bennett1984, Curley and Walski Reference Curley, Walski, Gennaro and Huenemann1999). On this kind of reading, even though there is a clear sense in which actual things can be considered contingent (E1p33, quoted above), there are merely possible, non-actual, contingent things. To support this reading, suppose again that every individual, actually existing, finite mode is necessary only relative to the other finite modes that determine it. One might then conclude that the entire infinite system of finite modes, the ‘actual world,’ does not follow from the absolute nature of God’s attributes alone. That would be analogous to invalidly inferring in formal logic that only one particular proposition follows from a general proposition. Now, because the actual infinite system of modes does not follow from what is absolutely necessary, it cannot itself be deemed absolutely necessary. Finally, if the actual world of finite things is not absolutely necessary, then one could say that there is a complementary sense in which other infinite systems of finite modes can be called possible. If E1p28 applied to them, such systems would not be ‘logically inconsistent’ with God’s unmodified, absolute attributes. Possible worlds characterized in this way seem to be ruled out by E1p33: “Things could have been produced by God in no other way, and in no other order than they have been produced.” This might, however, be countered by interpreting this proposition to require merely that there are no systems of finite modes consistent with some alternative laws of God’s nature because the actual laws of God’s nature are fully necessary. One might conclude on this interpretation of E1p33 that the actual laws of God’s nature are logically consistent with alternative systems of finite modes that therefore could, in some sense, follow from the actual laws.

It is questionable, however, whether such possible worlds are even intelligible for Spinoza. If they are unintelligible, that would seem to rule out a sense of real contingency that depends on such possible worlds. Spinoza would not, of course, allow possible worlds of the Leibnizian sort. For Leibniz, possible worlds are in the divine understanding; in Spinoza’s terminology, they “fall under the infinite intellect” (Leibniz Reference Leibniz, Ariew and Garber1989a, 71). Leibniz has it that God’s productive power is exercised on the best of all possible worlds. The omnipotence of Leibniz’s God does not actually extend to everything falling under the infinite intellect, but that is ruled out for Spinoza by E1p16. Furthermore, Spinoza addresses the closely related question of whether God would be equally perfect if things had been different from eternity in KV4, “Of God’s Necessary Actions.” In the colorful language of that text we find the answer that,

This would be incompatible with God’s immutability. Moreover, any deviation from supreme perfection would be less than supremely perfect. Here Spinoza is not prepared to admit any sense in which God could really be less perfect. In the Ethics, a connected point is developed in E1p33d:

Evidently, if possible worlds exist in Spinoza’s system, they must be understood in the bare, abstract sense of systems of non-actual somethings that are compatible with the necessary laws of God’s nature. They have to be systems of non-actual somethings and not random sets of individual non-actual somethings. Otherwise, E1p28 would not apply to the non-actual individuals. There cannot be ideas of such systems in the infinite intellect (E1p16) and that raises the suspicion that they are “fictions that are feigned” as a result of confusing words and ideas (E2p49s2, also see TIE[58]). And there can be no appeal to non-actual infinite intellects because the infinite intellect is absolutely necessary. One might try to defend Spinozistic intelligibility of non-actual possibles by appealing to E2p8, although this involves abstruse “formal essences”:

This proposition seems to allow that there are ideas (and perhaps, by E2p7, also bodies) of things that do not exist where their non-existence seems to be more than just the temporary non-existence of things that do exist at other times. These ideas of never-existing singular things cannot be ideas of determinate individual modes because E1p16 again requires that such ideas (and bodies) all follow from the infinite intellect and are all produced by God. Moreover, individual formal essences interpreted in this way obviously cannot be essences of determinate modes in an attribute regarded as absolute and unmodified. Setting aside the question of whether “God’s infinite idea” is the same thing as the infinite intellect, Spinoza in E2p8 must mean that when human minds construct ideas of non-existent things, these ideas must be conceived through the attribute of Thought or the attribute of Extension (Hübner Reference Hübner2015a). Spinoza’s geometrical example in E2p8s, and geometry more generally, similarly involve constructions of human minds that involve the imagination (E2p44c); there are no determinate Euclidean geometrical objects in the infinite intellect (Schliesser Reference Schliesser and Della Rocca2018). Human mathematical constructions, therefore, do not constitute a ground for real contingency. Moreover, while it is plausible that human minds can rationally construct ideas of definitions or essences of such singular beings of reason as geometrical items (as in E2p8s), this is obviously not possible for purely imaginary items like Pegasus or Cthulu even if those fantasies are supposed to be somehow consistent with the actual laws of God’s nature. They are fictions and not beings of reason of which one could have a true idea (TIE[55]). E2p8 by itself, therefore, does not seem to support any possibilities beyond conceptions dependent on human minds.

Having established that reason regards things truly as necessary (E2p44), Spinoza provides definitions of contingent and possible singular things in terms of the way they are imperfectly cognized.

Conceiving a singular thing as contingent in this sense requires that we do not attend to its cause, while conceiving it as possible requires ignorance of its being determined by its cause (E1a3). When “possibility” is distinguished from “contingency” in this way, the terminology is used in the evaluation of the intensity of emotional responses to things as follows. Affective responses are more intense, other things being equal, toward things imagined to be necessary rather than contingent or possible (E4p11). An affect toward a thing we know does not presently exist is more intense, other things being equal, if the thing is imagined to be possible rather than contingent (E4p12). That is because we imagine nothing positing the existence of a presently non-existing contingent thing while we can imagine a cause that posits the existence of a possible thing (E4p12d).

In conclusion, it is indisputable that Spinoza is a necessitarian of some kind. Examining the reasons Spinoza gives for the necessity of things, it emerges that one can stipulate different senses of “necessary”; for example, infinite modes follow either immediately or mediately from God’s absolute nature, and individual finite things do not follow from God’s absolute nature in quite the same way. This might lead us to say that Spinoza’s necessitarianism is not “maximal” or “absolute.” It is, however, not obvious to what independent standard of maximality or absoluteness Spinoza’s necessitarianism is being compared. Compared to Leibniz’s philosophy that has a God knowing and choosing among determinate, merely possible worlds, Spinoza’s necessitarianism is plausibly termed “fatal” or “absolute.” It is perhaps best to be satisfied with Spinoza’s own characterization of necessity without attempting to fit it into more generic theories of what real necessity amounts to.

Spinoza claims that all the various things that make up the world – people, plants, planets, etc. – are modes of a single substance. But what is a mode (modus)? Along with “substance” and “attribute,” “mode” is one of Spinoza’s basic ontological categories, which he defines as “the affections of a substance, or that which is in another through which it is also conceived” (E1def5). In other words, something is a mode if and only if it inheres in another thing, and conceiving the latter is required for conceiving the former. Many readers of Spinoza have thought that this definition itself stands in need of further elucidation. What is it for one thing to be in another and what is the relevant notion of conception?

In the seventeenth century, the term “mode” generally denotes an accidental property that stands in a relationship of asymmetric ontological dependence to its subject of inherence and predication. Spinoza’s definition, at least at first blush, appears to cohere well with this standard meaning. To begin with, modes are defined as “affections.” The term “affection [affectio],” in medieval and modern philosophical Latin, often refers to an accidental quality or state of some subject. Moreover, his phrase “that which is in another” calls to mind the Aristotelian notion of that which is present in another, which is a relation of asymmetric ontological dependence. In other respects, however, the definition of mode might appear to depart from the standard medieval and modern conception of an accident. In particular, Spinoza’s definition goes beyond the standard conception of an accident by adding a further clause: a mode is “conceived through” the substance in which it inheres. But this, too, can look to be a natural extension of the Aristotelian notion of an accident. Whereas substances can be defined or understood independently of their accidents, particular accidents, according to the Aristotelian tradition, must be partially defined or understood through their subjects (Carriero Reference Carriero1995). Spinoza claims that particular things are modes and, thus, at least some modes are particulars. Given that substances are generally thought to be the ultimate subjects of inherence, every (particular) mode must be partially defined by the substance in which it inheres.

Despite the apparent convergence between Spinoza’s definition of a mode and the traditional notion of an accident, there are reasons to question it. For example, as mentioned earlier, one of Spinoza’s most distinctive doctrines is that there is only one substance, God or nature, and all else, including finite bodies and minds, are modes of this substance. Some have found this thesis puzzling, if not outrageous. What could it mean to say that bodies and minds are properties or accidents of God? Accidents are the sorts of things that can be predicated of their subjects. Predication is the operation that takes us from a subject to a truth or a falsehood. For example, in and of itself, the sun is neither true nor false. But if we apply the predicate is hot to it, the result – the sun is hot – is either true or false. But how could we apply a body or a mind to a subject and thus derive a truth or a falsehood? Moreover, bodies and minds are particulars. How could any particular be predicated of something? For example, utterances such as Socrates is the brave are ungrammatical and nonsensical. What is more, bodies and minds themselves have properties that do not appear to be attributable to properties. For example, bodies have size, shape, motion, and so on. Does it make sense to say of any property that it has size or shape? (Of course, a particular red patch has size and shape, but it is the patch, not the property of redness itself, that has the size and shape.) Similarly, minds love and hate. But could any property love or hate? And yet if bodies and minds were properties, then some properties would have a shape and others would love and hate. These are serious problems.

One prominent solution to these problems comes from Pierre Bayle, who interprets Spinoza as saying that the properties that we commonly ascribe to bodies and minds are in fact properties of God (Bayle Reference Bayle and Popkin1991, Remark N). Thus, when we say that a body has a size and shape, what makes that true is that such a size and shape inheres in and is predicated of God. This solves the problem of predication by claiming that predicates are universals and bodies and minds are not really modes of God at all, but rather dummy subjects. The real subject of predication is God and the real predicates are the universals predicated of the dummy subjects, such as finite minds and bodies. However, Spinoza never says that finite bodies and minds are dummy subjects and indeed explicitly classifies them as modes. Moreover, as Bayle points out, this interpretation evades the difficulty of predicating shape and hate to properties only at the cost of incoherence because various bodies and minds satisfy incompatible predicates. For example, suppose that there are two bodies, one of which is square and the other of which is circular. On Bayle’s interpretation, God would be both square and circular. But this entails a contradiction as being both square and circular are logically incompatible.

Recent scholars have proposed other solutions to these problems. For example, some have suggested that we understand Spinoza’s “being in” merely as a causal relation and point out that causal relations do not entail predication (Curley Reference Curley1969, 19). Thus, Spinoza’s definition could be paraphrased as: “By mode I understand the affections of a substance, or that which is in – that is to say, caused by – another through which it is also conceived.” But this would make Spinoza’s use of the term “affection” in his definition exceptionally misleading, as it was typically understood in the seventeenth century to denote beings in the accidental categories and not merely any effect, regardless of ontological category. Moreover, it would make Spinoza’s thesis that there is only one substance and all else a mode of that substance subject to the charge that he is offering old wine in new bottles (as Bayle himself anticipates). There is nothing novel in claiming that God has no external cause and that everything else is caused by God.

Others have pointed out that the Aristotelian tradition recognizes particular accidents that inhere in their subjects but are not predicated of them (Carriero Reference Carriero1995, 258–59). For example, in addition to the universal cubicness that inheres in and is predicated of some box, there is also the particular cubicness of that box. The universal cubicness is shared with other boxes but the particular cubicness of this box belongs to this box and this box alone. But although such particular accidents inhere in their subjects, they are not predicated of them. After all, the utterance this cube is this cubicness is still unintelligible nonsense whether or not we include particular accidents in our ontology. And yet inherence of a particular accident appears to entail predication of a universal. After all, how could this cubicness inhere in a certain box if that box weren’t also cubic? But this would entail that God is the subject of contradictory predicates. Defenders of the particular accident interpretation sometimes respond by saying that – at least in the Aristotelian tradition – predications of contradictory accidents are only problematic if they are predicated in the same respects (Carriero Reference Carriero1995, 263). There is a violation of the law of contradiction if we say of a single subject that it is a square and a circle in the same respects but not if it is a square and a circle in different respects.

How should we understand these various respects that are supposed to insulate Spinoza from incoherence? A natural interpretation of Aristotle’s formula is that apparently contradictory predicates are not really so if they are ambiguous or involve an unstated parameter. For example, the statement the spinning top is both moving and not moving is not a contradiction if the first occurrence of is moving is interpreted to mean that its parts are changing location and the second occurrence is interpreted to mean that the top itself is changing location. But this is insufficient to insulate Spinoza from incoherence because many particular things in nature satisfy genuinely contradictory predicates as when Peter wants wine and Paul does not. Alternatively, a statement such as, for example, the poker is both hot and not hot, would not be a contradiction if there were an unstated relativization to parts such that the statement would be true if the tip were hot, and the handle were not. This too, however, is insufficient because if God is the only genuine subject of predication, then he is also the only genuine subject of relational predication. If Peter wants wine means that God wants wine relative to God and Paul does not want wine means that God doesn’t want wine relative to God, then that Peter wants wine and Paul does not entails a contradiction. Lastly, it has been suggested that adverbs of time and place can help Spinoza evade contradiction (Bennett Reference Bennett2001, 95). That God wants wine here and now does not contradict that God doesn’t want wine there and then. But adverbs of location are only relevant to the attribute of Extension, and adverbs of time are not enough because the mind of Peter might want wine at the very same time as the mind of Paul does not.

An alternative interpretative solution is to say that, for Spinoza, modes are not particular accidents. Rather they are accidental objects. A particular accident is an abstract feature or state of a subject such as the cubicness of this box or this cubicness. An accidental object, in contrast, is a concrete object – and as such a genuine subject of predication – that results from some subject satisfying a condition (Lin Reference Lin2019b, 112–15). For example, an origami cube is an accidental object that results from a sheet of paper being folded in a certain way. An origami cube is not an abstract state of the sheet of paper. It is a concrete object that instantiates first-order properties and stands in causal relations. Accidental objects are commonplace both in philosophy and in folk ontology. For example, Aristotle’s musical man is an accidental object that results from a certain man being musical. And ordinary objects such as waves, fists, wrinkles, and dents result from subjects (for example, oceans, hands, carpets, and surfaces respectively) satisfying certain conditions (oscillating, clenching, folding, sinking). On this interpretation, modes are accidental objects that result from God’s being certain ways. When Spinoza says that human minds and bodies are modes of God, he means that they stand to God as waves stand to an ocean. Minds are waves on the oceans of Thought and bodies are waves on the oceans of Extension.

Such an interpretation conforms nicely to one of the principal ways that Spinoza talks about modes: they are God quatenus (insofar as) he is affected or modified in some way. Just as a wave is the ocean insofar as it oscillates, so too the body of Socrates just is God (conceived of under the attribute of Extension) insofar as he Socratizes. It also evades the problem of predication. Just as waves are not predicated of the oceans in which they inhere, so too bodies and minds are not predicated of the substance, God, in which they inhere. And neither does a wave possessing a certain property entail that the ocean possesses that property. For example, the wave might have been caused by the earthquake but this would not entail that the ocean was caused by the earthquake. Thus, that Peter wants wine and Paul does not doesn’t entail the contradiction that God both does and does not want wine.

We have, thus far, been focusing exclusively on first-order finite modes. Does Spinoza believe that modes themselves have modes? Are there higher-order modes? The textual evidence is ambiguous. The definition of mode in E1def5 appears to restrict the modes to affections of a substance. Modes are not substances, and so, their affections are not modes. And yet Spinoza does occasionally speak of modes of non-substances. For example, in E2p17 Spinoza writes:

In the demonstration, Spinoza clearly states that a mode of the body is something that exists. Anything that exists must belong to some ontological category and thus it appears that non-substantial subjects can have modes.

Consideration of Spinoza’s discussion of modes of modes in E2p17 can also help us adjudicate between the competing interpretations of the modes as accidents (particular or otherwise) and accidental objects. If modes were accidents it would be difficult to see how modes of modes could change as the proposition clearly suggests they can. Let us assume, as is natural, that the changes that Spinoza speaks of involve changes to the body’s intrinsic properties. A subject undergoes real changes by acquiring and losing intrinsic accidents, but could an accident undergo real change in this way? It is hard to see how it could. But, if modes are accidental objects, the notion of a mode of a mode would be easier to understand. For example, if a sheet of paper were a mode of the extended substance, then the origami cube that results from this sheet of paper being folded in a certain way would be a mode of a mode.

In addition to finite modes, Spinoza recognizes infinite modes. In E1p21–23, Spinoza argues that whatever follows from the absolute nature of an infinite substance is itself infinite and eternal. His argument is convoluted, but it seems to boil down to this. If something finite were necessitated by the absolute nature of God, then there must be a time at which God’s nature exists and the finite thing does not. But the finite thing was stipulated to be necessitated by God’s nature. And so the imagined scenario in which God’s nature exists but the finite thing does not is impossible. Although Spinoza focuses on the issue of time, what goes for time goes for space. If there were a place where the finite thing didn’t exist, then it wouldn’t have been necessitated by the absolute nature of God, which is not spatially limited. What is necessitated by something pervasive and permanent must itself be pervasive and permanent. Moreover, the same arguments can be run for those things that follow from the absolute nature of an infinite mode and thus what follows from an infinite mode must itself be an infinite mode.

What are these infinite modes? When pressed in correspondence, Spinoza gives some examples: the infinite intellect and motion and rest are immediate infinite modes of Thought and Extension respectively; the “face of the entire universe” is a mediate infinite mode of Extension. (Spinoza doesn’t offer an example of a mediate infinite mode of thought but presumably the idea of the face of the entire universe is one.)

The natures of these mysterious entities remain a controversial subject among commentators. For example, with respect to the immediate infinite mode of motion and rest, some have identified it with local motion and its absence, others with force, and still others with derivative laws of nature. The situation with respect to the mediate infinite mode is a bit clearer as Spinoza himself points to E2L7s as elucidating the notion of the face of the entire universe. In that scholium, Spinoza describes how simple bodies come together to form complex bodies and how complex bodies can join together to form even more complex bodies. This process can be carried out to infinity, with the result that “the whole of nature is one individual, whose parts, i.e., all bodies, vary in infinite ways, without any change of the whole individual” (E27Ls). Some have concluded on this basis that the infinite mode whose proper parts are every finite mode of Extension is the mediate infinite mode of Extension (Schmaltz Reference Schmaltz1997; Garrett Reference Garrett and Yovel1991). Others have claimed that it is rather those physical features of the natural world that remain constant over time (Curley and Walski Reference Curley, Walski, Gennaro and Huenemann1999, 261n22).

It is necessary to conclude this entry with a word of caution. As discussed, “mode” for Spinoza is a term of art defined in E1def5 and employed by him in stating many of his most important doctrines. In ordinary contexts, however, the Latin word for mode (modus) means way or manner and Spinoza often uses it to express these nontechnical meanings. He does not in general give a clear indication of whether he is using it in its technical or nontechnical sense and his readers must work out which meaning he intends from context.

Spinoza introduces the model (exemplar) of human nature in the preface to Part 4 of the Ethics when setting forth his conceptions of perfection and goodness. Perfection, he explains, is often judged by recourse to an ideal or a model, for instance, when we judge the perfection of a house by comparing it to an ideal house. In the case of human artifacts, the model is determined by the intention or plan of the craftsperson. But we often judge the perfection of natural things in the same way, which mistakenly supposes that nature creates things in accordance with a plan, like a craftsperson. In this case, our model is based not on an intention or plan in nature, but rather on our own desires, preferences, and ideals. Furthermore, judging from models can also be mistaken because our models are often based on our general ideas of things, which report on our idiosyncratic experiences, rather than the essences of things (E2p40s1).

While Spinoza thinks that judging perfection from models is frequently erroneous, he does not seek to do away with models. Rather, he proposes that we form a model of human nature that we set before ourselves and use to judge human perfection and goodness:

Spinoza’s claims about the model of human nature raise difficult questions. Spinoza criticizes the models by which we judge natural things as mistaken because they wrongly suppose that nature is created with intentions and plans and because they are based on faulty generalizations and abstractions. Does Spinoza extend these criticisms to his own model of human nature, or does he propose his model as an alternative that avoids these criticisms? Some commentators (Jarrett Reference Jarrett, Kisner and Youpa2014, Newlands Reference Newlands2018) take the former view, which they take to imply that all judgments of goodness and perfection, even Spinoza’s own judgments in the Ethics, are inventions based on human desires, rather than the natures of things. On this basis, these commentators read Spinoza as claiming that all judgments of goodness and perfection are confused or mistaken because they wrongly suppose that nature acts with ends or purposes. Other commentators (Kisner Reference Kisner2011, NadlerReference Nadler2015, YoupaReference Youpa2020) take the latter view, which does not imply that all judgments of goodness and perfection are confused or invented. These commentators point to the fact that Spinoza’s model appears to be based on knowledge of the nature of things, specifically of human striving or conatus because Spinoza’s ethics judges things as good or perfect according to whether they promote human striving.

Most readers hold that we can learn more about the model of human nature from Spinoza’s claims about the free person, which are interspersed from E4p66 to E4p73. In E4p66s Spinoza asks the reader to compare a person “who is led only by an affect or by opinion, and one who is led by reason.” The former he calls a “slave” and the latter a “free” person. Since Spinoza’s ethics exhorts us to greater freedom, it is natural to suppose that this free person is the model of human nature, though Kisner (Reference Kisner2011, chap. 8) argues that there is little direct textual evidence for identifying the free person with the model.

Spinoza claims that the free person thinks about death least of all (E4p67), avoids dangers as much as facing them (E4p69), avoids incurring debts and favors to ignorant people (E4p70), is united in friendship and wholly grateful to other free people (E4p71), and always acts with honesty (E4p72). In addition, Spinoza holds that people become free by following reason, which entails that a free person will follow reason’s practical commands or dictates, including acting for the good of others (E4p73d, E4p37).

Spinoza’s account of the free person raises several challenging interpretive questions, which have divided commentators. First, it is unclear in what sense the free person is supposed to serve as a model for us. In particular, are we supposed to emulate the free person? It is natural to regard Spinoza’s descriptions of the free person as prescriptions for human action, which would imply that we ought to act with honesty, think least of death, and so forth. However, Don Garrett (Reference Garrett1990b) has argued influentially that because we are not ourselves free – or not as free as the free person – we should not necessarily act as a free person does. On this view, Spinoza is committed to claiming only that it is good for us to act in ways that help us to become free, but not necessarily in ways that a free person would act.

Garrett’s view is important to a second challenging question, how to interpret Spinoza’s perplexing claim that the free person would not lie even to “save himself from the present danger of death” (E4p72s). Spinoza asserts this claim on the grounds that free people act entirely from reason and adequate ideas, which direct us to be honest (E4p18s). The problem is that this claim appears inconsistent with Spinoza’s view that acting from reason means acting from our essential striving to preserve our lives and increase our power. “No one, therefore, unless he is defeated by causes external, and contrary, to his nature, neglects to seek his own advantage, or to preserve his being” (E4p20s; see also E4p21).

Garrett’s view provides a possible resolution of the apparent inconsistency. If Spinoza’s descriptions of the free person are not prescriptive for us, then E4p72s does not imply that we should give up our lives for the sake of honesty. As to why the free person would choose death over dishonesty, one might suppose that Spinoza’s free person has attained such a great degree of freedom and power that mere continued existence would not increase their power as much as acting in accordance with the rational directive to be honest.

A related, third challenging question is whether the free person is an attainable model. Many have answered in the negative (for instance, Kisner Reference Kisner2011, Soyarslan Reference Soyarslan2019). Indeed, Youpa (Reference Youpa2010a) has argued that the idea of a free person, understood as a perfectly free, finite thing, is unintelligible. There are three main reasons for thinking the free person is unattainable. Firstly, she “lives according to the dictate of reason alone” (E4p67d), which appears impossible for humans because, being limited, our rational powers will inevitably be overwhelmed by the opposing powers of external things, at least some of the time. “The force by which a man perseveres in existing is limited, and infinitely surpassed by the power of external causes” (E4p3). Secondly, Spinoza claims that a person born free, having only adequate ideas, would form no concept of good and bad (E4p68d). Since ideas of good and bad come from being affected by things that harm or help us, this suggests that the free person would not undergo any exogenous or passive changes, something impossible for human beings. Thirdly, Spinoza’s claim that a free person would die rather than lie suggests that a free person has attained an extraordinary degree of freedom – so much that continued existence would not increase her freedom – a state that appears unattainable for humans.

Nadler (Reference Nadler2020, chap. 3) has responded by defending the thesis that the free person is an attainable model. According to Nadler, the conclusion that the free person is unattainable is predicated on the notion that a free person is perfectly active and, consequently, possesses only adequate ideas – that is, ideas of which we are the adequate cause. Nadler argues that the free person is intended to be not a perfectly active being, but rather one who lives according to reason’s dictates. Since we can live according to these dictates and still possess passive, inadequate ideas, he concludes that the model of the free person is attainable for us.

If the model of the free person is unattainable, it further complicates the first challenging question of precisely how the free person serves as a model for us. Garrett’s view implies that the free person is not a model in the basic sense of a model for human action. Even if this is true, there remains a question as to how the free man is a model in the sense of a person that we aspire to become. How can we act in ways that help us to attain the model, if we know that we cannot attain it? It may be that the free person is an aspirational model, one that we strive for without reaching, although we can attain degrees of success in approximating the model. Such a model may still be useful for measuring our successes and development, in much the same way that a model of a perfect circle can provide direction and feedback for drawing circles, even if one can never draw a perfect circle.

The outward forms of different states, whether monarchies (monarchiae), aristocracies, democracies, or theocracies, are very elastic according to Spinoza. At the close of Chapter 7 of the TP, “On Monarchy,” Spinoza concludes that “a people can preserve quite a considerable degree of freedom under a king, provided that it ensures that the king’s power is determined only by the people’s power and depends on the people for its maintenance” (TP7.31). Spinoza evaluates the monarchies he analyzes – Aragon, Castile, England, and especially the ancient Israelite kingdom and that of ancient pre-republican Rome – less in terms of how efficient they may have been in their administration, upholding law and order, fighting wars, or defending their realms, than in terms of how effective their constitutional provisions were in restraining the power of the monarch. In his eyes the relevant measure was always how far the people remain the real sovereign power (potentia) behind the throne, and so how good the monarchies are at curbing tyranny and upholding the common good. He ends his chapter on monarchy by remarking “And this was the only Rule I followed in laying the foundations of a Monarchic state” (TP7.31).

Spinoza’s approach reflects his basic principle that democracy is the original form of society and that all forms of state are thus derivations from, and to a greater or lesser degree perversions of, human kind’s natural condition, including what Spinoza sees as our potential optimal form of state as regards individual and collective freedom, tolerance, self-expression and self-fulfillment. The best kind of monarchy is one like medieval Aragon, where very stringent constitutional limits constrain the king’s power, and the king acquiesces in this. A good monarchy is therefore a rare phenomenon and tyrannical monarchies that oppress their subjects a far more frequent one. Spinoza has many harsh things to say about the general character of monarchy in both the TTP and the TP. Once the ancient Hebrews placed themselves under kings, war and internal strife became the norm and everything slid downhill. Despite their consistent failure due to defects in their approach, Rome’s ancient republicans thus had excellent reasons for wanting to throw off the yoke of monarchy.

It was in Spinoza’s own time, though, the age of Philip II of Spain and Louis XIV of France, that the tendency to unrestrained absolutist monarchy reached its apogee as a model, mainly, as Spinoza saw it, due to monarchy’s appeal to nobles and ecclesiastics scheming to increase their own power. For no one person can know enough, or be sufficiently aware of what is going on around him or her, to genuinely be an absolute ruler. Hence, strong monarchy relies on subservient and corrupt aides mostly ignoring the welfare of society. Spinoza conceived monarchy, the dominant political form in Europe in his time, to be generally undesirable, a pernicious political ideology and defective frame of government, fundamentally detrimental to human happiness, and the factor chiefly responsible for the prevalence of war with all the misery wars cause. Resounding examples of this during his time were the Eighty Years’ War in the Low Countries (1566–1648) and the Thirty Years’ War that devastated Germany (1618–48), conflicts stemming principally from unrestrained dynastic and noble ambition allied to ecclesiastical and theological structures supportive of absolutist pretensions and arrogance.

Spinoza’s TTP has several purposes, among which are to defend his own views about “true religion” and how it differs from organized religious communities, about the nature of the state and political organization and its chief purposes, and about the relation between religion and the state. Although he refers once to his audience as “philosophical readers,” his primary audience are clergy who take Scripture to be authoritative and yet who are inclined to toleration and freedom of thought and expression. In short, in this work, Spinoza seeks to use Scripture to defend freedom of thought and expression by distinguishing the primary purposes of religion, on the one hand, and politics, on the other.

Given Scripture’s primary role in his argument, a large part of the TTP is taken up with discussion about and analysis of the Bible. And since the primary figure in the Pentateuch and other books of the Bible is Moses, it is not surprising that Spinoza has significant things to say about Moses. Moreover, since Moses plays a central role in Jewish thought, law, and liturgy, Spinoza’s treatment of Moses reflects his critical and revisionary thoughts about Judaism.

We can distinguish several aspects of Spinoza’s judgments about Moses. First, although Moses is traditionally taken to have written the entire Torah (Pentateuch), Spinoza appropriates well-known arguments from commentators such as Abraham Ibn Ezra and others in order to argue that evidence in the text itself encourages skepticism about Moses’ authorship of the entire Torah. Indeed, he argues that the Bible provides evidence that while Moses did write several works, to which the Torah is indebted, he in fact did not write the Torah itself.

Secondly, Spinoza agrees with the tradition that takes Moses to be a prophet and indeed the preeminent biblical prophet. Most likely with the treatment of prophecy by Moses Maimonides in his Guide of the Perplexed in mind, Spinoza argues that prophecy involves coming to understand the divine message through dreams, visions, and other imaginative means. Prophecy, Spinoza argues, does not involve rational inquiry and the study of nature. Its aims are to grasp and then communicate God’s desires for humankind, and, as indicated, prophets have the kind of imaginative gifts and abilities that enable them to perform such tasks. Maimonides had argued that Moses alone of all the biblical prophets communicated with God “face to face” and alone achieved intellectual perfection. Spinoza’s portrait of Moses explicitly opposes such intellectual accomplishment as a feature of Mosaic prophecy.

Thirdly, what role, then, did Moses as the preeminent biblical prophet play in the life of the Hebrew people? In Chapter 17 of the TTP Spinoza develops his distinctive version of social contract theory, influenced no doubt by his familiarity with Hobbes and others, in order to argue that the chief role of the state is to provide a peaceful and stable social and political setting in which individuals can seek to achieve personal fulfillment and to do so through acts of justice and benevolence toward one another. In addition to the rational arguments Spinoza provides for such a conception, he argues that it is endorsed by a responsible historical account of the emergence of the ancient Hebrews from Egyptian slavery and their decision to give Moses the authority to constitute a legal framework, as God’s representative among them, which they could institute once they had occupied the land in which their state could be established. Spinoza refers to this state as a “theocracy” and a “democracy,” and he takes its accomplishment – that is, the articulation of the laws of the state and the political decisions that brought the Hebrew people to the point where it could, after Moses’ death, be established – to be the result of Moses’ special legislative and political skills and abilities. In short, Spinoza takes Moses to be an exemplary political leader and legal mind, one who understood and could communicate the ultimate goals of an ideal state and who was attuned to what was needed to bring it into being. Indeed, this state was Moses’ goal as a political leader. He referred to the Hebrew people’s good fortune at having the right political and military leaders and at discovering the appropriate natural conditions in which to accomplish their political goals as the people’s “election by God,” and he instituted an array of ritual and ceremonial practices the chief purpose of which were to cultivate the people’s loyalty to the state and the God who ruled over it.

Finally, in Spinoza’s eyes Moses and Jesus differed as leaders and exemplars. Moses’ primary interests and abilities were oriented toward the particularity of political leadership and of the state. Jesus had no such interests. To him, as portrayed in the New Testament, the important goals of human life are universal and moral. Thus, Jesus could agree with Moses’s conviction that any particular state ought to nurture moral practices and humane and benevolent treatment of all people, but unlike Moses he had no interest in the particular institutional and communal organizations needed to realize these universal goals in social life. Philosophy – the inquiry into nature and understanding of it and the moral peace of mind and contentment it ultimately aimed at – was Jesus’ ultimate and primary aim, in Spinoza’s eyes; what Moses provided was an understanding of what would be required in order to seek philosophical knowledge and realize its goals in life.

During the drafting of the TTP, Spinoza still seemed quite skeptical about the judgment of the multitude (multitudo). In fact, he then used two main terms to refer to all citizens: either the people (populus) or the crowd (vulgus). Populus, in the chapters that analyze the Bible, designates the Hebrew people, as opposed to Moses or the kings, and the regime that preceded the monarchy was called “the kingdom of the people [populi regnum].” In the last chapters of the Treatise, devoted specifically to politics, the term also applies to the Romans, the English, the Dutch: it refers to those to whom laws are given and for whose “salvation,” that is, welfare, the republic is constituted; the people are the source of legitimacy, without necessarily being the actor in the story. The vulgus, on the other hand, is the passionate, ignorant, and superstitious mass, which is easily manipulated by theologians. At this stage, Spinoza seldom uses the word “multitude [multitudo]” and gives it an anthropological meaning close to vulgus: twice in the Preface he cites its tendency to superstition (TTPpref 8 and TTPpref 13); twice in the last chapters he emphasizes its inconstancy and cruelty (TTP17.14, TTP18.24); once he speaks of it in a less unfavorable manner, indicating that the prophets can lead the multitude to devotion (that is, justice and charity): in all these cases the multitudo is represented as passive and not as an agent of politics. One can read this judgment as an echo of the contempt of the common people that the reading of Latin historians transmitted to humanists and political theorists in the classical age.

Antonio Negri (Reference Negri1981) has shown that after 1670, Spinoza changed his conception of the state and its relationship with citizens: in the TP, the power of the citizens constitutes the right (jus) of the state, and this collective power is stronger as it approaches reason: “For the right of a commonwealth is determined by the power of a multitude which is led as if by one mind. But there is no way this union of minds can be conceived unless the commonwealth aims most at what sound reason teaches to be useful to all men” (TP3.7). It is therefore by the characters of the multitude that political freedom or servitude will be determined:

From now on, in the tradition of Machiavelli, the initiative of the citizens is the real condition of politics. It cannot be reduced to an initial contract, but extends natural law (jus naturale) into the life of institutions.