This article could be construed by some as quite mediaeval and scholastic, since it discusses a fundamental notion of theory of science with reference to theology—a link that to the modern reader may seem premodern at best and disconcerting at worst. Theology, even if it were granted a place among the humanities, perhaps would be the one furthest removed from the sciences as they are theorized and practiced today, for speculations on religious beliefs and the interpretation of holy texts do not comply with our contemporary standards of science. Yet, this article argues, the mediaeval debate, which began only decades after the inauguration of a project of scientific theology in the mid-thirteenth century, also scrutinized the scientific character of theology, and with some rather sobering results. Nevertheless, theological debate in mediaeval scholasticism continued to reflect upon theory of science, allowing theology—understood as lore from the hands of university theologians in the Middle Ages—to remain a valuable source for mediaeval epistemics, not least as to the limits of human science.
But throughout these scholastic debates, theology was also seen at least as a contender for being a realm of science or scientia. From an institutional point of view, this status was rooted in the mediaeval university, where from early on the academic discipline of theology was a living reality (Köhler Reference Köhler2022, 23–28). The question of whether and how theology complied with the relatively concise and strict framework of scientia, as it was debated in the Aristotelian tradition, was therefore both a pressing and an obvious one. For Aristotelians, scientia was characterized by at least three fundamental ideas: first, universality (scientia dealt with species and genera, not with individuals and particulars); second, causality, necessity, and apodicticity (scientia consisted of methods of proof from principles leading to logical certainty); and third, evidentness (as in having a clear notion of meaning and truth) (Köhler Reference Köhler2022, 14; Pasnau Reference Pasnau2017, 31–35). In the thirteenth century, philosophers argued that their own disciplines satisfied these conditions. Therefore, the Aristotelian notion of scientia seemed to be applicable to what was taught at the faculties of philosophy. For some theologians, this was reason enough to envision their discipline as scientia as well.
Nevertheless, the problem that the subtitle of this article sets out to discuss must seem to imply an anachronism that is difficult to reconcile with the fundamental points just touched upon. The claim of an emerging subjective science in the Middle Ages may seem to presuppose the imposition of modern notions of “science” and “subjectivity” (as a system of hypotheses and a Cartesian idea of cognition) on a mediaeval way of discussing the nature of organized knowledge. In fact, already here, on the level of the meaning of the word scientia, do the worries begin. Highlighting the contrast to modern notions of science, as it were, some mediaeval authors discussed scientia as an “academic discipline,” while others held it to mean first and foremost method(s) of proof, and yet others claimed that scientia is to be understood as “holding” insight into the truth of a single proposition (Meier-Oeser Reference Meier-Oeser2004). Sometimes these voices were not three or more but one and the same.
In order to unravel these preliminary difficulties, it may be wise to begin with the notion of “subject,” and more specifically with the one of “subject of knowledge” (subiectum scientiae). In mediaeval theory of science, this notion drew on the idea, going back to Aristotle, according to which “subject” (the Greek hypokeimenon) is something that underlies, or is referred to by, something else (Pronay Reference Pronay1984). Aristotle’s notion of the subject of knowledge, therefore, is analogous to the subject in a proposition: a subject (e.g. animal), of which for instance a property (e.g. rational) can be said or predicated. Following Aristotle, the mediaevals held that the subject of a science in the sense of “discipline” is unique to that science (Aristotle Reference Tredennick1960, 60–61), such that a given discipline in one way or another deals with knowledge about a unitary subject. Furthermore, of its specific subject, the respective science demonstrates the properties and essential attributes (ibid.). And finally, being a genus (genos hypokeimenon) or class of things—thus warranting the universality of the respective science—the subject also determines the science’s unity and identity. For anything known in a science is ultimately demonstrated of its single subject (Aristotle Reference Tredennick1960, 154–155). In contrast to this, Aristotle’s contention that it is the mind that is the “subject” of knowledge (Aristotle 1938, 14–15) played a minor role with regard to the notion of subiectum scientiae, not least because one mind could possess many kinds of sciences (Giles of Rome 1521, 2raB; Köpf Reference Köpf1974, 257–260).
However, Aristotle is not entirely clear as to the actual identification of the specific subject in a given science (Fiorentino Reference Fiorentino2014, 39–40). He can refer to such a subject as the syntactic and logical subject of a conclusion, which has been demonstrated by way of apodictic proof, thus taking what is predicated in that conclusion for the properties and essential attributes of the subject (Aristotle Reference Tredennick1960, 60–61). By identifying “extended magnitudes” as the subject of geometry and “numbers” as the one of mathematics, for instance, Aristotle also seems to describe as the subject a genus, species, or class of things (ibid.). In this case, the properties to be demonstrated would be the subject’s necessary characteristics. And finally, as with “points” and “lines” in geometry, the subjects of a science can also be particulars that fall under the science’s unitary genus (Aristotle Reference Tredennick1960, 70–71). One question these ambivalences in Aristotle raised in the Middle Ages was whether the subject of a science primarily is a concept, such as the logical categories of genus and species, or a thing that is known, like a particular magnitude or, for the sake of argument, a number that is known in a science. For the mediaevals, these things were what they called objects.
Aristotle conceived of any knowledge as a relation between two opposites (antikeimena): knowledge itself and the thing known (Aristotle 1938, 80–82). The mediaeval translators of Aristotle rendered the thing known, that is, a thing in the relation of knowledge, as oppositum, whereas the Aristotelian philosophers of the thirteenth century were the first to apply the term “object” (obiectum) to it (Dewan Reference Dewan1981). More broadly, then, objects in mediaeval Aristotelianism are things in some kind of relation to a psychological faculty, be it the senses, the imagination, the intellect, or the will. Hence, objects are not Dinge an sich or “cold” things. Rather a thing-as-object may be seen as “animated,” for it is by definition already related to a psychological faculty. An object is a thing-as-sensed, -imagined, -cognized, or -willed. Given these notions, “subject” and “object” must not be seen as complementary or downright opposed concepts, but rather as disparate ones. The breadth of their semantics concerns heterogeneous fields (Wöller Reference Wöller, Cordez, Kaske, Saviello and Thürigen2018).
In what follows, I will argue that in the second half of the thirteenth century, the epistemic notion of subiectum scientiae underwent a transformation from being primarily a concept to being primarily an object. I will show that this transition amounted to an epistemological turn in epistemics—a turn of this part of theory of science from a logical category toward the intellect. My discussion starts with Robert Kilwardby’s account of Aristotelian epistemics from the 1250s, where a fundamental manipulation of Aristotle laid the grounds for the said turn. In my reconstruction of this development, it was Thomas Aquinas who took the next crucial step. Aquinas accelerated, as it were, the epistemological turn, not least by coming up with an original account of the scientific nature of theology. Toward the end of the century, this latter issue stood at the center of a lengthy controversy at the University of Paris. I will touch upon this debate at the beginning of the third section of the article and present Giles of Rome’s contribution to it as the end point of the epistemological turn in epistemics reconstructed here. In the fourth section, I will point out some of the consequences of this development and conclude that we may see them as an emergence of what one can call subjective science in the Middle Ages.
The context of the argument is the mediaeval university, and the one in Paris in particular. There, debates on the limitations of knowledge about God at the faculty of theology contributed to a reorientation, not just of theology but of theory of science more generally. This reorientation is the object of my argument. Thus, I do not strive for a comprehensive reconstruction of Parisian debates on theory of science and theology in the thirteenth century, but rather for a fresh and selective reading of what I construe as the most momentous turning points in a history that is yet to be written.
1. Aristotelian theory of science at the mediaeval university: Robert Kilwardby
Ever since Martianus Capella’s fifth-century handbook on the liberal arts On the Marriage of Philology and Mercury (De nuptiis Philologiae et Mercurii), the use of the term “subject” (subiectum) to denote that which an art is about has been well established (Martianus Capella Reference Capella and Willis1983, 117). The high mediaeval monastery and cathedral schools, where Martianus and other guides on the arts were received, applied this terminology to the subject matters of the seven liberal arts: each art had one subject (Meier-Oeser Reference Meier-Oeser2004, 903). Thus, the Aristotelian sentence, according to which the subject identifies and unifies a science in the sense of “discipline,” fell on fertile ground when the Western mediaevals began to engage with Aristotle’s epistemics, put forward in the Posterior Analytics, in the twelfth century (Ebbesen Reference Ebbesen and Biard2015). In the course of this reception, however, what was determined by the subject as a unity was no longer the liberal arts but Aristotelian “sciences” (scientiae)—a transformation with dramatic consequences, both for the theory of science and for its context, that is, at the universities established around the year 1200 (Kluxen Reference Kluxen and Wieland1995).
During the first wave of university founding, the one in Paris led the European continent in the arts (later: philosophy) and in theology (Verger Reference Verger, Brungs, Murdoch and Schulthess2017, 49). In the first half of the thirteenth century, the “lower” faculty of arts was built upon the tradition of the twelfth-century schools and their program of the seven liberal arts—now, however, under the growing influence of Aristotle. The theologians of this period, teaching at the “higher” faculty of theology (which was only just emerging as a legal corporation), regarded the arts as propaedeutic and, not infrequently, suspicious disciplines, requiring doctrinal oversight to ensure that students would receive proper preparation for the study of theology (ibid., 48). The propaedeutic status of the “lower” faculty changed in the years 1254 and 1255 with two documents that can be regarded as the “hour of birth of the faculty of philosophy” (Schulthess Reference Schulthess, Brungs, Murdoch and Schulthess2017, 1117).
The first document, a letter written the University of Paris to all clergy and scholars, dated 4 February 1254, was the interim result of an ongoing conflict between the mendicant friars (Dominicans in particular) on the one hand and the secular masters on the other. The conflict was grounded in the friars’ hegemony, partially accomplished by circumventing corporate actions and institutional rules at the university. In this statement, the university complained about the mendicants, with the effect that the Roman pope revoked some religious rights from the friars at the university later that year (Wei Reference Wei2012, 114–118). The document begins, however, with the beautiful image of the university as “the fount of wisdom … that as if through the four rivers of Paradise, distributed in the four regions of the earth, irrigates … the whole world” (Chartularium Universitatis Parisiensis Reference Denifle1889, 1:252).Footnote 1 The four rivers in this document represent the four faculties, which are listed in order: the faculty of theology first, followed by jurisprudence, medicine, and the faculty “of rational, natural, and moral philosophy” (ibid.). This is the first known official record of a faculty of philosophy (not of the arts) at Paris.
Roughly one year later, on 19 March 1255, the philosophers issued the second document, containing new statutes for their faculty, and concluding formally, as it were, their emancipation from a propaedeutic to an independent status by prescribing the study of all known works of Aristotle. They embraced Aristotle’s philosophy and his epistemics for the disciplines taught at their faculty and assigned specific works from the Aristotelian corpus to the three parts of philosophy as defined in the document from 1254: rational, moral, and natural (ibid., 1:278). Taken together, these documents thus attest what quite probably was already established practice: a newly devised philosophy, based on Aristotle’s works, whose study had become a goal in itself (Schulthess Reference Schulthess, Brungs, Murdoch and Schulthess2017, 1117).
The theoretical foundations of this internal differentiation at the University of Paris were laid some time before the events just discussed. The work On the Origin of the Sciences (De ortu scientiarum) by the English Dominican Robert Kilwardby is an excellent example of this. Published around 1250 at the end of Kilwardby’s tenure as master of arts at Paris, this introduction to philosophy became an instant success. It figured among the books distributed by the university’s stationers (stationarii) as so-called pecia: single sheets that were rented out for copying successively, thus allowing for a rationalized distribution of high-quality copies among the university’s population, probably as required reading (Murano Reference Murano2005, 722–723).
Kilwardby divided philosophy into three parts: speculative (speculativa, with its further parts of natural philosophy, mathematics, and metaphysics), active (activa, with its further parts of mechanical arts and ethics), and discursive philosophy (sermocinalis, with its further parts of grammar, logic, and rhetoric) (Kilwardby Reference Kilwardby and Albert1976, 224–225). The work is permeated by Aristotle, be it in Kilwardby’s distinction between art and science—arts treat probabilities and contingents, while sciences discuss necessary truths (ibid., 145)—, in his subdivision of natural philosophy according to specific books of Aristotle (ibid., 23–29), or in the guiding principle of Kilwardby’s division of the sciences: it is a “division according to the subjects in the … parts of philosophy and thus [a division] of the parts of philosophy themselves” (ibid., 11).Footnote 2
Kilwardby developed his account of the subject of a science in a commentary on Aristotle’s Posterior Analytics, a work that partially depends on Robert Grosseteste’s commentary on the same work of Aristotle (ca. 1230). Like Grosseteste, Kilwardby assumes three fundamental characteristics of the subject of a science. First, a science cannot demonstrate its subject but rather supposes it (Kilwardby Reference Kilwardby and Cannone2003, 333). Second, the subject must be unitary in order for the science to be unitary as well (ibid., 294). And third, the subject, which is a genus, contains (a) all things or entities considered by the science and (b) the principles from which the properties of the entities, the species of the subject genus, and the necessary properties of the subject genus are being demonstrated. The subject thus unifies and identifies a science (ibid., 289; Corbini Reference Corbini, Lagerlund and Thom2013, 202–203; see also Kilwardby Reference Kilwardby and Albert1976, 21–22). Narrowing in on the subject as a genus, however, Kilwardby also argues independently from Grosseteste that this genus is of a different kind than the category of genus, for it has a different, more restricted internal unity, which is based on one single nature (natura). For instance, the category “quantity,” Kilwardby argues, predicates “a shared concept found in many entities,” but it does so via different intermediaries, namely natures, for instance “through the natur[e] … of the point” (Kilwardby Reference Kilwardby and Cannone2003–2004, 300).Footnote 3 The unity of the subject genus, therefore, is not logical but rather essential, for it is based on the nature that can be predicated by and, of all entities, considered by the respective science (Corbini Reference Corbini, Lagerlund and Thom2013, 203).
By redefining the genus that figures as the subject of a science, Kilwardby thus importantly removed from Aristotle’s account the ambiguity between the unity within the subject genus of wider and more restricted classes of things or entities. Whereas in Aristotle, the subject of a science could be both single entities falling under one nature—like “points” or “lines” in geometry—and a logical genus like “quantity” (see above), Kilwardby singled out the nature that is common to the entities considered in a science as the genus that is the subject of that science. This modification of Aristotle was to prove of signal importance for the following decades.
Kilwardby consistently employs this notion of “subject” in his On the Origin of the Sciences. However, at the outset of this work, he introduces a double meaning of “subject,” which he attributes to Isidore of Seville’s Etymologies (seventh century CE). “[There is a subject] about which (de quo) and [a subject] in which (in quo),” Kilwardby tells us. “The first is the universality of things divine and human; the second is the human being” (Kilwardby Reference Kilwardby and Albert1976, 10).Footnote 4 To be sure, the pairing “subject about which (de quo)” and “subject in which (in quo)” harks all the way back to the second chapter of Aristotle’s Categories and its sixth-century Latin translation by Boethius. Yet (as mentioned in the introduction), the “subject in which” was of only minimal importance in mediaeval epistemics. This is also true in On the Origin, where the “subject about which” is the decisive epistemic notion, as we have seen above with regard to Kilwardby’s division of philosophy.
Nevertheless, the “subject in which” is also integrated into Kilwardby’s account. Immediately after introducing the double notion of subject, he continues: “[Philosophy] thus originates first from the knowable things, then however from the human desire with regard to knowledge (scientia) and the good life (bona vita)” (ibid.).Footnote 5 Kilwardby argues that what philosophy is about (the “subject about which”) is the primary subject, whereas the human being (the “subject in which”) is secondary, but not as a secondary “subject.” Rather, Kilwardby bends this notion toward what he throughout the work addresses as the goal (finis) specific to each of the sciences. In the speculative part of philosophy, this goal recalls Aristotle’s ideal of theory and of the contemplative life (Kilwardby Reference Kilwardby and Albert1976, 13; Kenny Reference Kenny1992, 86–112; Köhler Reference Köhler2022, 194), whereas in the discussion on the goal of ethics, which figures as the common goal of all different parts of philosophy (ibid., 142–143), Kilwardby combines the Aristotelian with an Augustinian goal of science. The latter consists in “beatitude” (beatitudo) and the “enjoyment of God” (Dei fruitio) (ibid., 124–126; Maierù Reference Maierù, Lagerlund and Thom2013, 357–358).
As a legacy of early mediaeval thought, the Augustinian tradition never disappeared completely from philosophy and theology but continued to shape them in varying degrees. In this tradition, science as a function of the mind was thought to be complemented and ultimately superseded by wisdom (sapientia) as the goal of any rational inquiry. This goal consisted in the participation in God’s wisdom, which in Augustinian terms was identical with Christ, and consisted, on the human side, in the attainment of beatitude (Van Riel Reference Van Riel2019, 59–64; Köhler Reference Köhler2022, 210–212). For Kilwardby, the Augustinian ideal ranks higher than the Aristotelian. He contends that unlike the “catholics” of his own days, the philosophers of old age never attained this perfection of beatitude but remained on the lower level of immanent virtues. Their virtue ethics, however, “was not wrong but diminished, and thus it is not useless for the catholic [philosophers]” (Kilwardby Reference Kilwardby and Albert1976, 125).Footnote 6
More generally, Kilwardby envisioned the relation between philosophy and theology as a complementary one, albeit in a hierarchical setup. Theology (scientia divina), he argues, is “better than philosophy” (ibid., 14)Footnote 7 , for it is necessary and necessary for salvation in particular as “it contains the way to live, without which there is no salvation” (ibid., 9)Footnote 8 . Philosophy, however, although it is not sufficient for salvation, “is useful for the catholics, and they must cherish it” (ibid.). While theology originates from God without any human additions but is revealed to humankind, metaphysics (metaphysica, scientia divina, prima philosophia) (ibid., 84) treats God and the divine things as a philosophical discipline: it is devised by human reason (ibid., 14) and considers the things divine with regard to their nature (ibid., 195). In accordance with Kilwardby’s account of the subject of science, therefore, metaphysics has a proper subject consisting of the nature common to all entities, human and divine, considered by it: “being insofar it is being” (ens secundum quod est ens) (ibid., 83; Zimmermann Reference Zimmermann1998, 226–228). Thus, it is a science in Kilwardby’s Aristotelian sense; and an independent science at that.
Claims like Kilwardby’s led to competition and conflict between philosophers and theologians at Paris. The most momentous event in this respect was the 1277 condemnation by the bishop of Paris of 219 propositions that were being discussed at the faculty of arts. Next to propositions concerning the incompatibility of philosophical knowledge and church doctrine, it was the philosophers’ claim to hegemony and the resulting encroachment on theology that furnished the atmosphere of the condemnation. Claims like Kilwardby’s on the goal of philosophy consisting in beatitude, and the assertion that metaphysics, just like theology, addresses God and the divine things, only from a different angle, are reflected in the condemnation (Piché and Lafleur Reference Piché and Lafleur1999, 92 and 132; Schulthess Reference Schulthess, Brungs, Murdoch and Schulthess2017, 1117–1118).
2. God as the subject of theology: Thomas Aquinas
The condemnation of 1277 is a much-discussed event. Were the philosophers shut down? Was it a desperate attempt to preserve harmony between theology and philosophy? Or did it effectively articulate a secular, laical vision of scientia that could do without the authorities employed in theology (Flasch Reference Flasch1989)? There is evidence for each of these possibilities in the sources. The immediate consequence, however, was a further internal differentiation at the University of Paris. Turning now to the faculty of theology, the common ground with philosophy came under scrutiny, and among the problems to be debated in this respect, it was the scientific character of theology that continuously occupied the learned men. An important problem emerging from these debates focused on the capacities and limitations of human intellection in theology. One way to frame this problem was to ask whose intellect it actually is that meets the requirements for theological knowledge: whose science is theology?
On the background of the Aristotelian influence discussed in the preceding section, this question does not aim at the technical sense of the term “subject of knowledge.” Nonetheless, these two issues were related, as Thomas Aquinas’s account of theology as a science shows. Aquinas, a Dominican, studied and taught at Paris (on-and-off) during the decades that the preceding section of this article has discussed; he left Paris for good in 1272. Thus, he not only partook in the conflicts between seculars and friars and witnessed the growing confidence of the philosophers vis-à-vis the theologians, he also lived through what one may call a period of consolidation regarding the identity of theology as an academic discipline. For in the first part of the thirteenth century, university theologians were rather slow to adopt a consistent theory of knowledge (of whatever kind) for their discipline (Köpf Reference Köpf1974, 96–102). By 1250 however, two general directions materialized. The first conceived theology in an Augustinian tradition as a predominantly practical discipline, whose main goal consists in ethical perfection. A prominent proponent of this line was the Franciscan Bonaventure. The second direction, whose main exponent was Aquinas, held that theology was a predominantly speculative and only partially practical discipline, because it first and foremost aimed at the cognition of God (Köpf Reference Köpf1974, 198–207). And this it did in an Aristotelian framework.
In his late work The Summary of Theology (Summa theologiae, written ca. 1265–1273), Aquinas determined the subject of theology as God. For everything that is considered in theology is considered “under the aspect of God, either because it is God himself; or because it is orderly arranged toward God as its principle and end”Footnote 9 . This becomes clear, according to Aquinas, from the principles of theology, from which everything known in theology must be deduced. The principles are the basic tenets of Christian faith (articuli fidei), and because they are about God, the conclusions in theology—these are what is known in the strict sense—will also be about God. Thus, an “aspect of God” (ratio dei) unifies all the conclusions known in theology (Aquinas Reference Aquinas1888, 19). The fact that God is not a genus, as required of a subject by Aristotle, did not concern Aquinas, for the essential unity of the subject genus (as in Kilwardby), instead of a logical unity, had become a fixture in epistemics, not least in Aquinas’s teacher Albert the Great (Corbini Reference Corbini, Lagerlund and Thom2013, 203). Neither was it problematic that God cannot be scientifically demonstrated but is rather supposed, for the indemonstrability of the subject (as in Kilwardby) was also accepted by Aquinas (Zimmermann Reference Zimmermann1998, 204).
What for an Aristotelian was worrisome, however, was the “problem of the principles” (Köpf Reference Köpf1974, 142–149): for the principles of a science, which are axiomatic propositions on the science’s subject, must be evident in themselves in order for the conclusions deduced from them—and thus for the science as a whole—to be evident as well. But this is hardly the case with the tenets of Christian faith. Rather, they always require a source external to scientific theology—“the science of God and the blessed,” as Aquinas held (Aquinas Reference Aquinas1888, 9)—in order to become evident. Human theology, however, “believes its principles, which are revealed to it by God” (ibid.).Footnote 10 Aquinas did not eliminate the problem of the principles. Rather, he proposed an explanation as to why revealed theology does not lack a scientific outlook as a consequence of this fundamental problem. For theology, just like any science, depends on the human intellect and its powers. In this life, the human intellect may only know theological propositions according to a science which stands in an adequate relation to the intellect’s capabilities, since the intellect must be able to cognize everything that the science, which it “holds,” considers: “anything known is in the one who knows according to the one who knows”Footnote 11 (Aquinas Reference Aquinas1888, 167). This is to say that a science, according to Aristotelian terminology, is a habit (habitus) “held” by the intellect (Zimmermann Reference Zimmermann1998, 127–130 and 201–203; Wöller Reference Wöller2015, 228–231).
According to Aquinas, the habit of a science comprises all propositions, their terms, and the entities or things that are known in the respective science. As such, the latter are “objects” (obiecta); they are objects of cognition for the intellect. To be sure, one science considers many and seemingly disparate objects, such as God, human nature, and angels for instance in theology. Yet, according to Aquinas, the objects that are considered in a science all convene in a formal object or common aspect (ratio), such that under this aspect (sub ratione formali obiecti) they constitute a unity (Aquinas Reference Aquinas1888, 12; Wöller Reference Wöller2015, 159–160). In the case of theology, this common aspect of all objects that fall within the purview of theology is that these objects are “revealed” or “revealable” (Aquinas Reference Aquinas1888, 12). Aquinas thus determines the unity of a science as if from two angles: from an angle of theory of science it is the subject that unifies a science as a necessary condition, whereas from an epistemological angle the common aspect of the objects of a science performs this function as a sufficient condition (Zimmermann Reference Zimmermann1998, 202–205; Wöller Reference Wöller2015, 160–163).
Aquinas’s account of the subject-object as what unifies and identifies a science represents another important addition to Aristotle’s account of the subject of knowledge, as with Aquinas the intellect, its capacities, and its objects began to play a key role in mediaeval theory of science. His answer to the question “Whose science was theology?,” as posed above, was twofold: one science, whose objects are adequate to the intellect of the blessed, is the “theology of the blessed,” that is, of those human souls that after death are separated from their bodies and cognize God directly, whereas another science, whose objects are adequate to the human intellect in this life, is the revealed “theology of the wayfarers.” Both these sciences have the same subject—God—yet they consider this subject under different aspects of their objects. The aspect of the theology of the blessed is God’s essence, because their intellect is capable of this object, while revealed theology considers God and all its objects under the aspect of their being revealed or revealable (Livesey Reference Livesey1989, 34–38; Wöller Reference Wöller2015, 161–162 and 264–266).
3. God as the object of theology: Giles of Rome
The generation of Paris theologians after Aquinas saw this re-orientation of Aristotelian epistemics clearly and began scrutinizing more deeply the epistemological requirements for theology. Already two years before the 1277 crisis, the Augustinian Hermit Giles of Rome (like Aquinas a mendicant friar) discussed anew the subject of theology (Luna Reference Luna1990, 414–421) and involved the secular masters Henry of Ghent and Godfrey of Fontaines, two equally towering intellectuals, in a controversy that would protract until 1300. What was at stake in this debate was the very possibility of theology as scientia, and among the most contentious issues in this regard was the pointed question: whose science is theology? To this problem of the “ego” of theology, the three masters each adduced distinct solutions, with Henry vigorously defending the scientific character of professional theology and Godfrey defending an academic theology based on faith, not knowledge. I will return to Godfrey and Henry in the concluding section of the article. Giles tended toward Godfrey, but unlike Godfrey, he boldly turned the Aristotelian terminology around.
In the prologue to his Commentary on the First Book of the Sentences from 1275, Giles declares that “the subject in a science is the object”, and more precisely, it is its “principal and formal object” (Giles of Rome 1521, 2ra)Footnote 12 because it is the intellect that “holds” a science as a habit. Unlike Aquinas, however, Giles argues that this principal object is not an aspect common to all objects of a science. Rather, the subject of a science is that very object which is considered for its own sake, first, principally, and in every aspect (per se et primo et principaliter et per omnem modum; ibid., 2rb) in a given science. Any other objects are only studied in the same science, inasmuch as they are ordered toward the principal object or are its parts, such that the unity of a science is the unity of its objects (Zimmermann Reference Zimmermann1998, 169–173). Metaphysics and theology both consider God, Giles claims, but metaphysics considers principally, and in every aspect, “being as such” (ens in eo quod ens; Giles of Rome 1521, 2rb). “Being as such,” therefore, is the principal object that determines the unity of metaphysics. In consequence, metaphysics also studies God as “being as such,” and not as its principal object. Some twelve years later, Giles stated that metaphysics scrutinizes God just like all objects “under the aspect of ‘being’” (sub ratione entis; Giles of Rome 1646, 130a), while theology considers God principally and in every aspect. Thus, it is correct to say that, according to Giles, God is the principal object that determines the unity of theology as a science (ibid., 129a; see also Giles of Rome 1521, 3vb).
Giles shows occasional inconsistency in his terminology, using “object” and “subject” interchangeably.Footnote 13 Nevertheless, his insistence that it is the object which assumes the role of the subject in unifying and identifying a science marks the completion of the notable epistemological turn in the debate on the subject of a science. For Giles, the principal object—a thing being cognized—is a sufficient condition for unifying and identifying a science (Giles of Rome 1521, 6ra). What further underlines this epistemological turn is that the cognizing faculty also plays an important role in the constitution of a science. The “light (lumen) of the agent [human] intellect,” Giles tells us, “provides a certain actuality to the single knowable things and concomitantly to the single sciences” (ibid., 5vb).Footnote 14 In and of itself, this actualization of all cognizable things does not yet determine the unity of a science, but rather figures as a necessary condition of knowing any object. Thus, in order for there to be a unified science, a principal object must be determined from among all objects knowable. This also applies to theology; however, in this case, it is not the human intellect that actualizes the single knowable things but God himself—the “divine light” (lumen divinum)—which having thus actualized all objects knowable to God gives rise to God’s own theology by considering God himself as its principal object and all other objects as ordered toward him (ibid.).
However, Giles argues, the principal object of divine theology in its all-encompassing universality does not provide the unity required by theology as known by the human intellect. For in order for this theology to be able to consider all its objects as ordered toward God as its principal object, this principal object must be further specified by a special aspect (ratio) (ibid., 6ra). Such a special aspect is nothing particular to theology. Rather, it is required by any specific science, which Giles distinguishes from a general science such as metaphysics. As we have seen, the principal object in metaphysics is “being as such.” This is a general object, Giles argues, and thus the aspect under which metaphysics considers all objects knowable is general as well (Giles of Rome 1521, 3va). In contrast to this, natural philosophy has the specific object “mobile body” (corpus mobile), which is specific precisely because the notion “mobile” specifies the genus “body.” Hence, also the aspect has this specificity, for natural philosophy considers all its objects under the aspect of being mobile (Giles of Rome 1646, 129a).
Now, the challenge to human theology is that it has the same principal object “God” as God has in his theology. Unlike God in his own theology, however, human theology clearly does not consider all objects but only those “by which the most saving faith, which leads to blessedness, is begotten, nourished, defended, and strengthened” (ibid.), as Giles clarifies with an influential quotation from Augustine (Brown Reference Brown, Berndt, Lutz-Bachmann and Niederberger2002). For instance, “vain and noxious things” (Giles of Rome 1646, 129a) do not fall into the realm of human theology. Therefore, theology must be considered a specific science that, as such, looks at its principal object under a special aspect of the principal object. Giles eventually declares that this aspect is “God inasmuch as he is the glorifier and the restorer [of human nature]” (ibid., 131a; see also Giles of Rome 1521, 3va; Nash Reference Nash1956, 64–66 and 72–75; Cross Reference Cross, Charles and Peter2016, 43).
We have now come full circle in Giles’s account of the unity and identity of a science. “In any science one has to note three [identifiers]: the thing which the science principally considers [i.e. the principal object], the aspect under which it considers, and the light through which it considers” (Giles of Rome 1646, 129a).Footnote 15 Accordingly, human theology considers God under the aspect of him glorifying and restoring human nature, and it considers all its objects through the “light of faith divinely infused into us” (ibid., 129a-b). These identifiers distinguish human theology from any science held by the human intellect (ibid.). Just like Aquinas, therefore, Giles assumes that what unifies theology needs to be revealed by God and believed by men. Giles holds that this is the principal object and a specific aspect of this same object, not both an aspect common to all objects considered in theology and the unitary subject, as Aquinas held. Giles even attacks Aquinas directly by arguing that if the latter proves the unity of a science by postulating a unity of aspect (unitas rationis), he is forced to base this unity on the “unity of light,” that is, of the intellect which, as we have seen in Aquinas, takes an adequate aspect. Aquinas’s “unity of aspect,” therefore, presupposes the “unity of light” so that “one proves unity with unity, and that is to beg the question” (Giles of Rome 1521, 5vb).Footnote 16
Giles offers a threefold typology of theology consisting of God’s theology, the theology of the blessed, and the “human science” (Giles of Rome 1664, 129b) of theology. These three, he declares, all convene in one and the same principal object: God. Yet, while only God considers himself “absolutely and for his own sake” (ibid.), both the theology of the blessed and human theology consider him under the specific aspect of him being the glorifier and restorer of human nature. But it is the “light through which” God is known that ultimately distinguishes these theologies: God knows himself through himself, “which is an uncreated light” (ibid.), the blessed know God through a clear yet created light, and humans in this life know him through an “enigmatic” light, that is, through faith (ibid., 130a). If compared with God’s science, revealed theology is derivative because of the specific aspect under which, and the light of faith through which, it considers God. Nevertheless, revealed theology scrutinizes the same principal object as God does in his theology (ibid., 130b). Moreover, because of its excellent object, revealed theology is elevated above all sciences held by the human intellect. Metaphysics, the “queen of the sciences” (ibid., 131b), which includes God among its objects, ranks second, while all other sciences are third (ibid.). Hence, despite the human intellect’s limitations, Giles seems to offer an optimistic account of theology on the basis of its object.
With regard to Aristotle’s scientific criterion of apodicticity, however, Giles’s revealed theology yields a less optimistic result. For how may a science about God, through faith under a restricted aspect that is directed toward the goal of beatitude (as Giles concluded with Augustine), produce logical certainty by way of deductive proof? It simply does not. Rather, revealed theology “nourishes, defends, and strengthens the most saving faith,” to use Giles’s quote from Augustine once again. An example of this epistemologically limited theology dates back to the time before Giles left Paris to pursue an ecclesial career in 1277. In the treatise Theoremata de corpore Christi (ca. 1274/76), Giles weighed in on the thorny issue of the eucharistic body of Christ, responding to various theories that attempt to explain how bread is converted into the real body of Christ on the altar. To these he responds, quite personally: “This did Christ bequeath, this is also what the church holds. … Whoever is not satisfied with this … may inquire respectfully and dreadfully into what this body [of Christ] is. I myself (ego) prefer to persist in my simplicity rather than rashly judge difficult matters” (Giles of Rome 1554, 23rb).Footnote 17 Here, Giles’s theological “ego” does not prove, but simply accepts its truths.
Giles expressed this somber account of revealed theology even more strongly after his return to Paris in 1285. In his fifth Quodlibet from 1289 or 1290, he again argued for the superiority of revealed theology over any human science. But it is the superiority of the theology of the blessed over revealed theology that eclipses any human reasoning, revealed theology included. For what we can know is always limited by our cognition, which cannot do without sensible experience (Pini Reference Pini2005; König-Pralong Reference König-Pralong2020). As a result, “the blessed see clearly what we [only] believe … and they can laugh at us ‘who darken counsel by ignorant words’. So even if we refute all arguments against the faith, we will never sufficiently explain and prove the truth of faith” (Giles of Rome 1664, 286a; the biblical quote is from Job 38:2).Footnote 18
Because of this insurmountable incompatibility between revealed theology and that of the blessed, Giles’s answer to the question “Whose science is theology?” needs to be refined with regard to revealed theology. For from his contention that the identity and unity of a science is determined by an object that, as such, is cognized by an intellectual faculty, Giles derived a strong notion of the “ego” of theology: in order to say whether or not I know something in theology, I first have to become aware of my intellectual capacities. Revealed theology, therefore, is always “my” theology. But this theology is not a science, at least not in the Aristotelian sense. Rather, in an Augustinian sense, it is a discipline that strives to understand and defend the contents of faith, which are accepted from a higher authority such as Scripture or the church. For the fact that it is “my” theology, determined by the limits of my cognition, also limits its scientific character and acumen. In this current state of my existence, my theology is a function of my faith rather than my intellect.
4. Toward subjective science
For Giles, the path he travelled, between the 1270s and circa 1290, from the epistemological turn in the debate on the subject of a science to his pessimistic statements about revealed theology as a consequence of the limitation of human cognition, was a long one. But it also was a consistent one, since the common denominator throughout this process was Giles’s focus on the role of the cognizing faculty and its object for the identity of a given science. But how did he grow so weary of human intellectual capacity? Was it the pessimistic “cultural climate” (Pini Reference Pini2005, 530 and 538) at the faculty of theology around and after the condemnation of 1277, a period of heightened alert as to the perils of science? Or, perhaps in addition to that, did the long-lasting controversy about the scientific character of theology with Godfrey of Fontaines and Henry of Ghent make him adopt this ultimately unscientific account of theology?
Godfrey of Fontaines adopted a position similar to Giles’, yet on different grounds (König-Pralong Reference König-Pralong2020, 83–84). He attacked Giles’ notion of a special aspect, arguing that revealed theology as a specific science is inferior to metaphysics as a general science (Nash Reference Nash1956, 69–71). According to Godfrey, in order to warrant the superiority of theology at the mediaeval university, revealed theology must consider its subject, God, in his universality “under the general aspect, under which anything cognizable can be attributed to him by the believer” (Godfrey of Fontaines Reference de Wulf and Pelzer1904, 14).Footnote 19 Godfrey thus returns to the notion of “subject” for what unifies and identifies a science: the infinite God as the subject of theology is that to which the finite human intellect can attribute anything knowable. The principles of this attribution, however, lack the evidentness required by the principles of a science because they are not known but rather revealed to the human mind. Godfrey argued that theologians thus believe their principles, just as simple believers believe the basic tenets of faith. For instance, if one asks an unlearned believer whether he or she “believes this or that [concerning the eucharistic sacrament], they will answer plainly: ‘I believe’. Also a most learned scholar will answer thus” (Godfrey of Fontaines 1924, 70).Footnote 20 The theologian surpasses the unlearned believer only by an advanced understanding of Scripture; hence he will add: “because I understand Scripture, I not only believe … but I know because I know that Scripture teaches thus. But not that I grasp with my intellect what is taught in Scripture. Rather I grasp [by faith] that this is taught in Scripture” (ibid.).Footnote 21 I, the theologian, only know that my authorities teach the truth, not why, because the principles of these teachings are not evident to me (Brown Reference Brown, Berndt, Lutz-Bachmann and Niederberger2002, 254–259). Thus, theology is not a science, for “nobody can have a properly scientific habit of what belongs to faith” (ibid.).Footnote 22 And in consequence, the “ego” of theology, according to Godfrey, is that of the simple believer.
Henry of Ghent looked at any such attempts to approximate theology to faith as the ruin of theology as a science. “It is a great wonder,” he remarked sarcastically in 1288, “that in any other faculty, an expert strives to elevate his science as much as possible, but certain theologians, in order to seemingly exalt philosophy, debase theology by asserting that it is not truly a science, and that the contents of faith cannot become truly intelligible in this life” (Henry of Ghent Reference Decorte1987, 20).Footnote 23 Henry consistently defended the scientific character of theology with two major arguments. First, like Godfrey, he insisted against Giles that God is the subject of revealed theology without any special aspect. However, more consistently than Godfrey and similar to Giles, Henry also maintained that the subject of a science has the characteristics of an object (Pickavé Reference Pickavé2001, 502–508). Henry thus must be seen as another representative of the epistemological turn in the debate on the subject of a science. And secondly, against both Giles and Godfrey, Henry argued that theologians in this life are endowed with a privileged access to the truths of faith. Through this “clearer light” (lumen clarius), which is given by God, theologians are granted an understanding of the terms that make up a theological proposition. For Henry, this meant that by the grace of such divine illumination, theologians understand, for instance, the meaning of the terms “God,” “one,” and “three,” but still accept by faith that these terms form propositions like “God is one and triune” (Työrinöya Reference Työrinöya and Holmström-Hintikka2000; Wöller Reference Wöller2015, 83–88). The “ego” of theology, therefore, is the professional theologian, the aristocratic clergyman, endowed by God with particular intellectual acumen (König-Pralong Reference König-Pralong2011, 81–90).
Taking stock of the debate on the subject of theology at the end of the thirteenth century at the University of Paris, three conclusions emerge. The first is that both Giles of Rome and Godfrey of Fontaines remarkably often wrote about theology in the first person, thus addressing the problem of the “ego” of their discipline openly on the literal level (some examples are given above). But as important as this phenomenon of academic language may be, the theoretical background of this linguistic choice is all the more important. For this debate, which started out as one on the subject, became one about the object of theology. And this is my second conclusion. The initiator of this turn from subject to object was Giles, when he stated that the subject is the object. He began by refining Aquinas’s theological epistemics, completing, as it were, an epistemological turn that had already begun with Aquinas. Giles thus reorientated epistemics from subject- to object-centered in the mediaeval Aristotelian sense: what unifies and identifies a science became a thing cognized, and thus also the cognizing faculty was brought into the center of the debate. My third conclusion is that the epistemological turn led to fundamentally different views on the “ego” of theology, with Godfrey and Henry going as far as to identify the theologian with a specific social group or category. As the clash on this matter between Giles, Godfrey, and Henry shows, the problem of the “ego” of theology played a decisive role in the assessment of the scientific character of theology. It therefore may not be an overstatement to say that the mediaeval theologians, by considering the limitations of human science in the light of divine science and that of the blessed, seriously jeopardized the project of scientific theology.
To be sure, these were developments conditioned by rather specific epistemic problems in theology and constellations of debate at the University of Paris in the second half of the thirteenth century. However, the subsequent history of mediaeval theory of science, which I can only allude to here, clearly shows that the focus on the object and its corresponding faculty of cognition kept increasing, with consequences reaching well beyond theology. An innovative conclusion was drawn by William of Ockham in the second decade of the fourteenth century. Arguing that a science has as many subjects as it has propositions, Ockham gave up the notion of a unitary subject that could identify and unify a science. Rather, any science is an aggregate in the intellect, as Ockham claimed: a number of habits of the intellect, each “holding” one proposition with its own subject, with a logical order pertaining among these individual habits thus forming a unified science (Pelletier Reference Pelletier2013, 26–49). Therefore, in order to scrutinize any science, the aggregate of habits “held” by a given intellect must first be taken into account. Put differently, before knowing anything scientifically, the one knowing must first intuit her intellect and thus experience herself as a “permanent subject” (Balibar, Cassin, and De Libera Reference Balibar, Cassin, de Libera and Cassin2004, 1242). It is tempting to see this epistemic innovation, which was based on the epistemological turn in theory of science—toward the object—as the emergence of subjectivity (De Libera Reference De Libera2007) in mediaeval science.
Acknowledgements
This research is co-funded by the Danish National Research Foundation (DNRF138). I am indebted to the guest editors of this special issue of Science in Context for including my article and their helpful remarks on an earlier version. Furthermore, I am grateful to Martin Klein (Graz) for critical discussion and to two anonymous readers who greatly helped with improving the article. Last but not least, I would like to thank the editorial team of Science in Context, Yossi Schwartz in primis, for their diligent work with my contribution.
Florian Wöller is Associate Professor in Church History at the Faculty of Theology, University of Copenhagen (Denmark). He received is PhD from the University of Basel (Switzerland) in 2015. The doctoral thesis, turned into a book, appeared with Brill in 2015 (Theologie und Wissenschaft bei Petrus Aureoli). He has since continued his work on late medieval theology and science and developed a research agenda in religious and cultural history in late antiquity. Wöller has published widely in both areas, including Dominican Culture, Dominican Theology: The Order of Preachers and Its Spheres of Action (2025), edited with Ueli Zahnd.
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