BACKGROUND

Stoicism is a philosophy of moral rigor. This rigor has given rise to two stereotypes. First, a Stoic either has no feelings or successfully suppresses them. Second, the Stoics' belief in an all-encompassing fate only leaves humans with the option of readily complying with its predetermined order. If compliance with fate is the bottom line of Stoic philosophy, what could be more reasonable than an unemotional resignation to its ineluctable decrees? Though in antiquity both friends and foes had a much more complex view of Stoic philosophy, its particular version of determinism was the target of attacks by members of rival schools from early on. What could be the point of moral reflections and an active engagement in life's concerns if everything is fated to happen anyway? The debate on the question of the compatibility of fate with human responsibility therefore never ceased during the five hundred years of that school's existence.

Though the long and intensive intellectual life of the school makes it unlikely that its entire philosophy was based on inherently contradictory principles, the continued attacks and counterattacks at least suggest some tension in the type of determinism fostered by the Stoics. What then, is the gist of Stoic determinism and in what way is it compatible with their insistence on an active life in compliance with carefully worked-out moral principles? Since pioneers like Pohlenz, Sambursky, Long, Rist, and Sandbach have drawn attention to the intricacies of Stoic philosophy, the debate on Stoic compatibilism in secondary literature has steadily increased, and to this very day the question has not been settled to everyone’s satisfaction.

THE STEREOTYPE

According to a stereotypical view, Stoicism in the period of the Roman Empire was philosophically uncreative. The 'school' had an ill-defined institutional status and there was a good deal of eclecticism and merging of different philosophies. The dominant theme was ethics, and the main surviving works consist of exercises in practical moralising based on ideas mapped out centuries before. Unsurprisingly, in the later part of this period, Stoicism was replaced as a living philosophy by a revived Platonism and by a form of Christianity that was increasingly more sophisticated and theoretically aware.

Like all stereotypes, this one contains an element of truth; but it obscures important respects in which Stoicism continued as an active philosophical force for at least the first two centuries a.d. Although there was no institutional ‘school’ as there was in the Hellenistic Age, there were numerous Stoic teachers, and the distinctive three-part Stoic educational curriculum was maintained, with important work continuing in all three areas (i.e., logic, ethics, and physics). As well as being the dominant philosophical movement in the period, Stoicism was also strongly embedded in Greco-Roman culture and, to some extent, in political life, and the ideal of living a properly Stoic life remained powerful. In the third and fourth centuries a.d. and later, Neoplatonic and Christian writers built on key Stoic ideas and absorbed them into their systems.

Stoic Sages never make mistakes. Secure in their understanding of the providential structure of the world, which is identical with fate, which in turn is identical with the will of Zeus (DL VII 135, =SVF 2.580; Plutarch, St. rep. 1049f, 1056c = SVF 2.937; cf. 2.931, 2.1076), Sages order their lives in accordance with it, assimilating their will to the will of Zeus, living in accordance with nature, and so achieving the smooth flow of life, the eurhoia biou so devoutly to be wished for (DL VII 87, =SVF 3.4; Cicero, Fin. III 31, IV 14-15, =SVF 3.15, 3.13; cf. 3.4-9, 3.12-16).

It seems clear enough that if the Sage is to be anything more than an unattainable, regulative ideal (and that is a big ‘if’), the Stoics need powerful reasons, in the form of a powerful epistemology, for supposing that such practical infallibility can ever actually be attainable. And even if the Sage is supposed only to be an ideal figure (and the Stoics were doubtful whether such a superhuman ethical cognizer ever had existed: Sextus, M IX 133, =54D LS; Alexander, Fat. 199.16, =SVF 3.658, =61N LS), still, for the ideal to function as anything more than a piece of remote wishful thinking, it had better be possible at least to approach that ideal; and the Stoics did indeed set great store by the notion of prokopê, moral and cognitive progress (Stobaeus V 906.18–907.5, =SVF 3.510, =59I LS).

In Stoicism, as in Epicureanism, an understanding of the physical place of humanity in the universe was an integral component of a system of thought underpinning each sect's ethical commitments. At the same time as these schools flourished, non-philosophical disciplines were evolving that laid claim to knowledge of parts of this subject: astronomy, which concerned the composition and regularity of the heavens in their own right; geography, which investigated the form and characteristics of the earth and its inhabited parts; and astrology, which asserted connections between the celestial motions and mundane life. The fundamental assumptions of these scientific disciplines were from the start so completely at odds with Epicurus' atomistic, aleatory cosmology that Epicureanism and the exact sciences were doomed to a relationship of mutual irrelevance so long as they coexisted. Between Stoicism and the sciences the possibilities of interaction were greater; though, as we shall see, there were limits to their readiness to embrace each other's approaches.

ASTRONOMY

The central matter of astronomia as it was commonly understood up to the Hellenistic period was the organization of the stars into their constellations and the association of their annual cycle of risings and settings with patterns of weather and human (mostly agricultural) activity.1 But Eudoxus’ astronomical works, which are known to us only through excerpts and secondhand reports, exemplified and indeed likely pioneered a considerable expansion of the science’s scope: in addition to the traditional topics of constellations, weather patterns, and calendrical cycles, he investigated conceptual geometrical models that sought to account for the phenomena of the heavenly bodies and that could be interpreted as reflecting the physical nature of the cosmos.

PHASES

The history of the Stoic school is conventionally divided into three phases:

• Early Stoicism: from Zeno's foundation of the school, c. 300, to the late second century b.c.: the period which includes the headship of the greatest Stoic of them all, Chrysippus

• Middle Stoicism: the era of Panaetius and Posidonius

• Roman Stoicism: the Roman Imperial period, dominated by Seneca, Epictetus, and Marcus Aurelius

Although the Stoic tradition’s continuity is at least as important as any resolution into distinct phases, the traditional divisions do reflect key changes which no school history can afford to ignore. The following account will, in fact, assume a rough division into five phases, despite acknowledgment of extensive overlaps between them:

1. the first generation

2. the era of the early Athenian scholarchs

3. the Platonising phase (‘Middle Stoicism’)

4. the first century b.c. decentralisation

5. the Imperial phase

The primary ground for separating these is that each represents, to some extent, a different perspective on what it is to be a Stoic – that is, on what allegiances and commitments are entailed by the chosen label.

The phrase 'traditional grammar' refers to the body of knowledge about the correct use of word-forms and syntax transmitted in the West at least since the early Middle Ages for the study of Latin and Greek and whose categories were used as a template for the study of other languages. It has long been recognised that traditional grammar shares numerous terms and concepts with the linguistic studies of the Stoics, and this chapter examines the relations between them.

SOURCES

As is so often the case with Hellenistic philosophy, the dearth of reliable, high-quality, first-hand material is a serious obstacle to reconstructing Stoic thought in this area. No Stoic grammatical treatise of any period survives; indeed, only one text with what can be called, broadly, grammatical interests is extant in even something like its original form; in any case this book of Chrysippus’ Logical Questions (PHerc 307) belongs rather in what moderns would call philosophical logic and the philosophy of language – although this overlap is significant in itself (see Section 2.2).

INTRODUCTION

According to Diogenes Laertius, most of the Stoics - beginning with Zeno of Citium - divided philosophical doctrine into three parts: one physical, one ethical, and one logical. Diogenes also reports three homely similes concerning the relation among these parts of philosophy: (1) philosophy is like an animal, with logic corresponding to the bones and sinews, ethics to the more fleshy parts, and physics to the soul; (2) philosophy is like an egg, with logic corresponding to 'the outside' (shell), ethics to 'what is in between' (the white), and physics to 'the innermost part' (yolk); and (3) philosophy is like a productive field, with logic corresponding to the enclosing fence, ethics to the crop, and physics to the earth or trees.

Whatever the precise import of these similes might have been, it seems clear that the Stoics held that physical doctrine stands in an intimate relation to ethics. For the Stoics, the end of human life is ‘to live conformably with nature’ (to homologoumenon têi phusei zên). Consequently, physics – that part of philosophy that pertains to nature and that reveals the import of living ‘conformably with nature’ – obviously has ethical import. Logically distinct from this aspect of the relation of physical doctrine to ethics is a second point of connection between the two: the common contemporary assumption that it is both possible and desirable to undertake a ‘valueneutral’ investigation of nature is quite foreign to Stoic thought. Indeed, it is common to find what might be termed large-scale Stoic philosophical themes influencing physical doctrine – including some of the rather technical aspects of Stoic physical doctrine. In particular, the Stoic themes of the unity and cohesion of the cosmos and of an all-encompassing divine reason controlling the cosmos are of fundamental importance to Stoic physics.

The object of Stoic theology was the governing principle of the cosmos, insofar as this could also be labeled 'god'. The Stoics accordingly regarded theology as part of physics, more specifically as that part which does not focus on the details and the purely physical aspects of cosmic processes, but rather on their overall coherence, teleology, and providential design, as well as on the question of how this cosmic theology relates to popular forms of belief and worship. Issues covered by Stoic theology include the nature of the divine principle of the cosmos, the existence and nature of the other gods, our proper attitude toward the gods - that is, the virtue of piety (eusebeia) and the opposite vice of impiety (asebeia), including our attitude toward traditional myth and ritual - and issues relating to fate and providence, including the way the providential ordering of the cosmos can be known by mankind by means of oracles and divination.

Whereas the founding father of the school, Zeno of Citium, still appears to have published his theological views in the context of his main cosmological work On the whole, his successors accorded a more prominent position to theology as a subject in its own right. Cleanthes explicitly set off theology from the rest of physics, or from physics in the narrow sense (DL VII 41), and wrote a separate work On the gods. Persaeus wrote a work On impiety. Sphaerus appears to have been the first Stoic to have written a separate work On divination. Chrysippus published not only an On the gods and an On Zeus, but also works specifically devoted to fate, providence, divination, and oracles. He appears to have followed in Cleanthes’ footsteps in treating theology as a separate subdiscipline. At any rate he claimed that it was the part of physics that was to be treated last, thus putting it at the final stage of the curriculum (the study of physics as a whole coming after logic and ethics).

Stoic logic is in its core a propositional logic. Stoic inference concerns the relations between items that have the structure of propositions. These items are the assertibles (axiômata). They are the primary bearers of truth-values. Accordingly, Stoic logic falls into two main parts: the theory of arguments and the theory of assertibles, which are the components from which the arguments are built.

SAYABLES AND ASSERTIBLES

What is an assertible? According to the Stoic standard definition, it is

This definition places the assertible in the genus of self-complete sayables, and so everything that holds in general for sayables and for self-complete sayables holds equally for assertibles. Sayables (lekta) are items placed between mere vocal sounds on the one hand and the world on the other. They are, very roughly, meanings: ‘what we say are things, which in fact are sayables’ (DL VII 57). Sayables are the underlying meanings in everything we say or think; they underlie any rational presentation we have (S. E. MVIII 70). But they generally also subsist when no one actually says or thinks them.

The histories of philosophy and medicine in the ancient world are deeply intertwined. Some individuals we think of as philosophers had serious medical interests (Empedocles and Sextus Empiricus, for instance); rather more doctors exhibited a more than merely avocational interest in philosophy (Alcmaeon, Diocles of Carystus, Herophilus, Erasistratus, Asclepiades, Menodotus, and preeminently Galen). The treatises of the Hippocratic corpus are full of philosophy; and both Plato and Aristotle paid due attention to medicine.

Perhaps the most important single instance of the cross-fertilization of ideas between physician and philosopher consists in the great debate about the nature of science and the limits of epistemology conducted with equal vigour between the skeptical schools and their medical colleagues the Empiricists (and later the Methodists) on the one hand, and the various Dogmatic sects of both philosophy and medicine on the other. Indeed, even the terminology is revealing: anti-theoreticians in both the medical and the philosophical camps standardly refer to their opponents as Dogmatists.

INTRODUCTION

In one of the talks 'after class' given by the Stoic Epictetus, he is recorded as warning his audience against supposing that they can turn themselves into professional teachers of philosophy overnight, simply by rehearsing the principles they have worked up. His remarks include this intriguing passage (III 21.18–19):

Two things are immediately obvious: (1) In talking of Socrates, Zeno, and the Cynic Diogenes in this way, Epictetus is not doing history of philosophy. These great names – of thinkers who lived over four or (in Socrates’ case) five hundred years previously – are simply his authorities and paradigms. (2) Epictetus is not thinking of Socrates, Zeno, and Diogenes as authors or proponents of distinct although no doubt related philosophies, as they would standardly be presented in modern accounts of Greek philosophy. The implication is rather that there is one philosophy – or one thing, philosophy – but that the three of them each adopt a different mode of communicating it to others: a different mode of ‘care’, or what one might roughly and in generic terms call ‘therapy’.

Three Stoic doctrines have heavily influenced the course of later moral philosophy: (1) Eudaemonism: the ultimate end for rational action is the agent's own happiness. (2) Naturalism: happiness and virtue consist in living in accord with nature. (3) Moralism: moral virtue is to be chosen for its own sake and is to be preferred above any combination of items with non-moral value. These Stoic doctrines provide some later moralists with a starting-point and an outline that they try to develop and amplify. These moralists include supporters of the position that I will call 'Scholastic naturalism'. For other later moralists, Stoicism provides a target; they develop their own positions by explaining why they reject the Stoic position. Still others defend some of these Stoic doctrines and reject others.

For obvious reasons, my account of the influence of these Stoic doctrines will be highly selective. I will simply sketch Scholastic naturalism through a few remarks about Aquinas, Suarez, and Grotius. On the other side, I will examine Pufendorf’s reasons for rejecting Scholastic naturalism, and the attempts of Butler and Hutcheson to defend some Stoic doctrines while rejecting others.

My interest in these reactions to Stoicism and Scholastic naturalism is primarily philosophical. I hope to understand how different people argue for or against these doctrines, and to see how reasonable the arguments are. It will be clear that I cannot complete this task in this one chapter; I will simply try to identify the main arguments and to raise some relevant questions about them.

A TWO-PART THEORY

Like Darwin's own theory of evolution, the modern Darwinian theory of evolution has two main elements:

The first of these propositions says that any two contemporary organisms have a common ancestor. Human beings are genealogically related to each other, but each human being also has a common ancestor with chimps, dogs, clams, daffodils, bacteria and yeast. The second proposition, as I have formulated it, does not say that natural selection is the only cause of evolution. Indeed, it should be understood to leave open the possibility that there are traits for which natural selection is entirely irrelevant. This is the big picture, and evolutionary biology is devoted to filling in the details.

Although Darwinism is easy to describe, this simple theory gives rise to a rich range of metaphysical and epistemological questions. It is the purpose of this chapter to discuss some of them. In conformity with the structure of Darwinian theory, I have chosen one metaphysical and one epistemological problem from each of the two big ideas. I begin with a problem in the metaphysics of natural selection – the role of chance – followed by a problem in the metaphysics of the tree of life – the nature of a biological species. Turning from metaphysics to epistemology, the later sections of the chapter examine the testing of hypotheses about genealogical relatedness (the tree of life) and the testing of adaptive hypotheses (natural selection).

ORIGINS AND CHARACTER OF THE ORIGIN

Reading On the Origin of Species is a rite of passage for many biologists and its reasoning continues to play a pivotal role in biological thought. It is often said, following Darwin himself, that the Origin is 'one long argument' (459). There is something important in this remark. Readers expecting the Origin to be structured around a narrative account find the book perplexing. Unlike the paradigmatic early Victorian book on evolution, the Edinburgh journalist Robert Chambers' Vestiges of the Natural History of Creation, published anonymously in 1844, the Origin was not written as a history of life's evolution on earth. Rather, the Origin was structured as an argument. Hence, Darwin's insistence that his book was one long argument provides an indispensable clue for reading the text. But it is not clear that it should be read as one argument. Although Darwin may have designed his book to be read as one long argument for evolution by means of natural selection, many of his readers must have read it differently. We know this because the Origin persuaded many readers to accept the 'evolution' idea but not the 'by means of natural selection' part of Darwin's view. These readers were not swayed by one long argument for evolution by means of natural selection. So, to understand the reasoning that influenced Darwin's readers, it is better to think of the Origin as a body of argumentation flexible enough to allow readers' views of the reasoning to differ from what Darwin might have intended. The aim of this chapter is to provide a guide to the Origin's flexible and sometimes elusive body of reasoning.

THE PERSISTENCE OF DARWINISM

For nearly one-and-a-half centuries, biologists interested in evolution have been haunted by the question of whether their conceptions are or are not 'Darwinian'. While it may not be unique, this persistent positioning of new developments in relation to a single, pioneering figure is quite exceptional in the history of modern natural science. Physicists currently working in the domains of relativity or quantum theory may refer sometimes to Einstein or Bohr; but their debates are not massively structured by this reference as evolutionary theory has been and remains structured by reference to Darwin. A proximate cause of Darwin's enduring presence is that evolutionary biologists have never stopped reading him. The remarkably numerous editions and translations of Darwin's books have in themselves helped to make this possible. But the availability of key texts only takes us so far in understanding why evolutionary biologists go on reading Darwin, referring to him, feeling the necessity of labelling their theories as 'Darwinian' or 'non-Darwinian' or 'anti-Darwinian'.

Indeed, on the face of it, there are compelling reasons for modern biologists to avoid affiliating their work with Darwin’s. Darwinism does not belong only to the history of science; it also belongs to cultural and political history.1 Among other things, neo-liberal economics, social Darwinism, racial anthropology, Nazi ideology and the materialistic monism of Darwin’s German supporter Ernst Haeckel had strong interactions with Darwinism in the first century of its history. Likewise, in more recent times, sociobiology (in its more ideological forms), American liberalism and the European right-wing have been more thoroughly committed to Darwinism than their opponents.

DARWINISM, NATURALISM AND HUMAN AFFAIRS

Among philosophers, naturalism is the view that contemporary scientific theory is the source of solutions to philosophical problems. Naturalists look to the theory of natural selection as a primary resource in coming to solve philosophical problems raised by human affairs in particular. For the theory combines relevance to human affairs and scientific warrant more strongly than does any other theory. Theories in physics and chemistry may be more strongly confirmed, especially because their more precise predictions can be tested in real time. But these theories have little to tell us about human conduct and institutions. On the other hand, actual and possible theories in the social and behavioural sciences may in the future have more to tell us about humanity than Darwinian theory; but these theories do not as yet have anything like the degree of confirmation of Darwin's theory.

This chapter surveys contemporary strategies for providing a Darwinian understanding and vindication of morality, ethical norms, our conception of justice, and the cooperative human institutions which those norms and conceptions underlie. We will see that while the prospects for a Darwinian vindication of moral claims – as true or well founded – remain clouded, the prospects for explaining the normative dimension of human affairs by appeal to Darwinism appear to be improving. Indeed, the emerging evolutionary understanding of why human beings have been selected to be moral agents may come as close to a vindication of morality in human affairs as naturalism will allow.