This is the first book in a new series of Cambridge University Press on “Key themes in ancient philosophy”. As the editors of the series explain in the front matter, the books in this series are to offer “a concise and accessible treatment by a single author of a topic of major philosophical importance in the ancient Greek and Roman world” (ii). Moreover, books in the series are designed for a teaching context, in which they are intended to “bridge a gap between general introductions to individual philosophers or periods and specialist monographs” (ii). And of course an appeal is claimed for that universally wooed reader of the day, the educated and interested non-specialist.
These are worthy objectives. But the author of this, the first volume of the series, actually attempts to do a good deal more. In his interpretation of ancient (actually almost exclusively Greek) theories of knowledge, Gerson makes a very particular and ambitious case for their contemporary relevance. These theories provide, he argues, real alternatives to modern theories that fallwithin the ambit of “naturalized epistemology”, the Quinean program of explaining knowledge as a natural phenomenon properly studied by empirical science. In connection with this bold interpretive thesis Gerson advances another, more general claim. It is that the analysis of knowledge in terms of rationally justified, true belief, a central theme in epistemology after Descartes, is in fact considered and rejected in Plato’s Theaetetus, whereupon the explication of knowledge in terms of belief never again figures prominently in the history of ancient philosophy.
These are spectacularly controversial claims, and anyone who should make them convincing in a short book with little scholarly apparatus would achieve the improbable. I hold that Gerson falls short of substantiating his general theses, but I find many things of interest here, particularly in his discussions of Hellenistic philosophy. In the following, I summarize and discuss Gerson’s arguments chapter by chapter, and conclude with a brief assessment of these two main interpretive claims.
In Chapter One, on “Ancient and modern perspectives”, Gerson sets out the guiding thesis of his study, which also serves to describe the common denominator of “ancient epistemology”: “What makes it possible to speak generally about ancient epistemology is that all the philosophers with whom I shall be concerned shared the belief that knowledge is a natural state or a ‘natural kind’ and that it is possible to have incorrect or correct accounts of what that is” (2). This the reader must understand to be only a common and not a constitutive element of ancient philosophy, for as Gerson has stated on the very first page of his book: “Broadly speaking, from the beginning of ancient Greek philosophy up to Descartes, epistemology was viewed as both naturalistic in its shape and content and as irreducible to the enterprise that we would call empirical science” (1).
The alert non-specialist might well infer from this that ancient epistemology is of a piece with the rest of pre-Cartesian theories of knowledge, and that the focus upon ancient authors is presumably just a matter of convention and convenience. Such an unsuspecting reader might, furthermore, be led to assume at this point that authors like Parmenides or Albertus Magnus had the option of resorting to something that “we could call empirical science” for explaining what knowledge really is, but that they and others decided against reducing questions concerning knowledge in this way.
All this is more than a little controversial. Gerson’s impetus for making such claims seems to be derived from a strongly held view on what ancient epistemology is not, or how ancient theories of knowledge must not be understood. They are not to be understood using the background assumptions of what Gerson calls the Standard Analysis of knowledge, a model often invoked in modern epistemology. According to this model, a subject S knows a proposition p iff (i.e., if and only if) (1) p is true; (2) S believes p; and (3) S is justified in believing p. This model of knowledge is commonly attributed to Plato (among others). In this introductory chapter and elsewhere, Gerson argues vigorously against this attribution, and for the claim that knowledge, according to ancient accounts, is not a species of justified, true belief. Ancient theories of knowledge cannot be understood in terms of the Standard Analysis because: 1. unlike the concept of propositional knowledge in the Standard Analysis, the ancient concepts of knowledge do not claim that knowledge is reducible to “knowledge-that”; 2. ancient theorists of knowledge did not think that knowledge was merely a kind of belief. With respect to 1., Gerson holds that, on the concept of knowledge implicit in ancient theories, knowledge is rather like a physical state such as fever or pregnancy, and not a psychological disposition to a proposition And with respect to 2. Gerson specifies this state as a non-propositional kind of highest cognition, thus preparing a prominent place for a theory of thinking and mind in his account of ancient epistemology. But these assumptions too are highly controversial, so they cannot really be said to justify the grand narrative on the history of epistemology that Gerson proposes at this point. I shall come back to his arguments for these assumptions in regard to the various phases and figures of ancient philosophy.
In Chapter Two, Gerson discusses pre-Socratic philosophy under the programmatic rubric “The origin of epistemology”. Epistemology, Gerson tells us, has its origin in Greek philosophy, and Greek philosophy begins with a thesis: that “nature” (
Chapter Three, on Plato, is important for the argument of the book as a whole, for here Plato is interpreted as considering and rejecting the Standard Analysis model of knowledge in the Theaetetus. After a very brief discussion of an early dialogue and the early-middle Meno, Gerson embarks on a relatively long discussion of the Republic V-VII. His main aim here is to show 1. that knowledge and belief must, according to Plato’s argument in Rep. V, have mutually exclusive objects, and 2. that Plato conceives of knowledge as non-propositional. The latter claim in particular has far-reaching consequences which one would like to have at least named, if not carefully considered. How, for example, must we then understand the role of forms in generating something like propositional knowledge? Or does the author of the Republic have no interest in anything like propositional knowledge? At least the Theaetetus would provide some indication that something like propositions are not wholly irrelevant to Plato’s thinking on knowledge. These are questions and issues which Gerson cannot address in any detail; and yet they would have to be addressed in much detail to even get off the ground.
Gerson’s fourth Chapter, on Aristotle, is centred on the Posterior Analytics and De anima. Gerson locates epistemological interests in the Aristotelian corpus generally in claiming that the “overall task” of the Organon is to provide “an account of the structure of the knowable such that we can understand how knowledge is acquired” (64). This could be nuanced a bit: the works of the Organon are motivated by concerns which are “epistemological” only in particular senses of the modern term. The theory of proof and methodology of the Posterior Analytics is developed through discussing some problems concerning the objects and acquisition of knowledge, but the theory as a whole is concerned with demonstration, and it operates upon the basis of the extremely demanding concept of <κ>ἐπιστημή <!—κ—>. Gerson sets out the outline of this theory ably, but then yokes this to a discussion of belief and knowledge which seems peripheral within the Posterior Analytics (it occurs in the rather isolated An. Post. A 33, 88 a 30 ff.). His account for the value of this passage – and of the distinction between belief and knowledge – for understanding Aristotle’s theory of demonstration as a whole were not immediately clear to this reader. In any case, the Analytics seem to be a bad place to look for a theory of knowledge which stipulates that knowledge is non-propositional (with the exception, perhaps, of the very last chapter).
For this, then, Gerson turns to De anima III.3-8, in which the natural basis for human thinking and cognition is identified and distinguished from the process of sensation. The main thesis motivating Gerson’s interpretation of these famously difficult and contested passages is that, for Aristotle, knowledge is a species of non-propositional cognition. In particular, Gerson forwards an interpretation of the highly difficult account of thinking in De an. III.5 which suggests a strong continuity with Plato: the cognition which is knowledge is a type of self-thinking of objects distinct from sense-perception. An adequate discussion of this topic would far exceed the scope of this review. But it must be said that is also exceeds the scope of Gerson’s discussion, which – interesting though it is – will be hard for beginners in ancient philosophy to understand, while lacking the detail required for making a scholarly case for such a controversial thesis concerning such a disputed text.
In Chapter Five Gerson treats Epicureanism together with the Old Stoa, arguing that these are “two schools of philosophy that … share a type of naturalism in epistemology that is self-consciously materialist” (90). Though the denomination of Stoic theories as “materialistic“ contains a certain prejudice (“corporealist” is perhaps a more nuanced description 1), Gerson would seem to have in the Stoics and Epicureans genuine allies in his endeavour to naturalize ancient epistemology. For Epicureans and Stoics alike did indeed deem knowing to be a physical state, and knowledge to be based upon the senses. It is on account of this that Gerson’s general argument on the development of epistemology begins to be more persuasive at this point. Interestingly, he is also much less insistent on these claims in this and the following two chapters, which are in my view the betters ones of the book.
Chapter Six treats theories of knowledge in three stages of ancient skepticism: “Pyrrho and the beginnings of skepticism”, “Academic skepticism”, and what Gerson calls (in quoting Long and Sedley 2) a “Pyrrhonist revival”, the recourse to Pyrrhonic arguments by Aenesidemus. In this chapter Gerson departs from the two main theses of his book and concentrates on the these three periods of skepticism and the reconstruction of the theories of knowledge in each. This made for informative reading supported by references to the main passages, and a chapter which was introductory in a good sense.
In Chapter Seven Gerson undertakes the bold and difficult task of wresting from the Enneads a coherent and briefly describable body of ‘epistemological’ theory. Still, Gerson is here in his element, and he presents a dense account with copious references to the Enneads. This reviewer is not familiar enough with these texts to judge Gerson’s presentation here, but I did find that the close proximity to the primary sources in this chapter makes for an informative introduction to the general outlines of Neo-Platonic philosophy.
In Chapter Eight, on “Varieties of naturalism”, Gerson finally gives the reader a brief introduction to the philosophical views which form much of the background for his own thinking on epistemological issues. I wish that this chapter had come at the very beginning of the book, for it is revealing with regard to his reasons for positioning ancient theories of knowledge as generally concerning non-propositional knowledge and as being recalcitrant to problems related to the Standard Analysis. The agenda of modern philosophical naturalism was set by the desire, much in the spirit of Positivism, to put philosophical questions squarely within the domain of empirical science – or exclude them altogether. Gerson interprets ancient philosophy in this spirit by making its enemy out to be very much like the enemy of modern naturalism: a “criteriological” approach to knowledge which takes its problems from skepticism about the external world. While it is true that skepticism about the external world is quite foreign to even ancient skepticism, and it is right that ancient philosophers submit to an epistemic ideal called “science”, there is much potential confusion in making ancient philosophy out to be a”variety” of naturalism. Ancient philosophy never had to contend with the dogmas of empiricism, and it is not just jaunty anachronism to imply that ancient philosophers consciously opted out of, say, reducing experience and knowledge to propositional content. To the contrary: ancient philosophers lacked the concept of the “empirical” which was crucial for the development of some of the positions modern epistemological naturalists rejected.
Respect is due Gerson for his admirably broad knowledge of ancient philosophy. His book also manages to establish a continuous narrative in the history of philosophy which is strikingly coherent, even if many will disagree with Gerson on the degree of continuity he finds between particular figures and schools. This said, I find his arguments for the interpretation of ancient philosophy as a kind of epistemological naturalism unconvincing, at least in regard to pre-Hellenistic philosophy. Gerson’s point about the fundamental difference between knowledge and belief in ancient philosophical theories of knowledge and modern ones is well taken. But frequent recourse to the Standard Analysis to press this point imports issues which obscure the discussion of the texts he discusses. In addition, in certain parts of the book, such as the chapter on Aristotle, Gerson bases his arguments on controversial interpretations of disputed and difficult texts, so that there is little he can prove with them, at least in a book with few references and little room for scholarly debate. The reader will therefore require much more than casual knowledge in ancient philosophy to assess or even understand these passages. Nonetheless, Gerson’s views are often refreshingly provocative, even if one misses his own discussion of some of the difficulties they entail.
1. On the many implications of the Stoic theory of corporeals see Katja Maria Vogt, “Sons of the Earth: Are the Stoics Metaphysical Brutes?”, in: Phronesis, Vol. 54 (2009), 136-154. I wish to thank her for pointing out to me the derogatory and imprecise use of the label materialist with regard to the Stoics.
2. See A. A. Long and D.N. Sedley, The Hellenistic Philosophers, Vol. 1, Cambridge 1987, 468.