This volume is a collection of fourteen previously published essays, many of which have been revised and translated into English for the first time. As a collection it is to be commended for its consistency and unified methodology. The work culminates in a reading of Plato's views about the limits of human reason: knowledge, understood as direct or unmediated apprehension of the forms, is impossible for embodied human beings. T.’s sustained effort to defend such a weak epistemology on the part of Plato will prove useful and interesting, if only as a foil, for all those investigating the structure of knowledge in the dialogues.

The first six chapters advance an interpretation of the Theaetetus, according to which epistêmê is doxastic in nature and therefore fallible. The three chapters that follow examine the Cratylus and the central books of the Republic, mounting an attack on the intuitionist view, which claims that knowledge is possible through direct apprehension of the forms. The central arguments of the volume conclude in a reading of the Parmenides, whereon Plato's forms are not metaphysical realities; rather, they are inferred from sensible particulars without independent confirmation. The final chapters bolster this deflationary metaphysical interpretation with evidence from Aristotle, re-examine the Third Man Argument in its light, and address the challenges of reconciling such a weak metaphysics and epistemology to the ambitious philosophical projects described in the Republic and Laws.

Given the breadth of the work as a whole and the space restrictions of this format, it will be best to avoid the finer points of T.’s interpretation of any one dialogue. These remarks focus instead on the central claim of the volume, developed in the first six chapters and expanded upon in the rest of the work, that epistêmê is inescapably doxastic in nature.

In Chapter 2, ‘Logos and Doxa’, the failure of the three definitions of epistêmê in the Theaetetus is taken as evidence for the view that logos, and knowledge therefore, can never ‘fully transcend’ or ‘free itself’ from doxa (p. 28). Knowledge is necessarily doxastic, on this view, because ‘it is only through logos (i.e. through reasoning of some sort, albeit [sic] only embryonic reasoning) that the soul acquires the possibility of distinguishing – by granting its assent – between opinions which strike it as true and opinions which strike it as false’ (p. 28). That knowledge requires a logos, then, seems to be what renders it fallible.

However, it is worth considering why logoi are, on this account, responsible for the fallibility of knowledge. Unfortunately, the arguments for this claim are somewhat opaque. In Chapter 1, ‘Thought as Inner Dialogue’, T. adopts the position that human opinion, thought and reason (doxa, dianoia and logos) are essentially mediated by language and propositional in nature. In Chapter 3, in a discussion of the Second Sailing, the view that logoi are propositional turns out to be a key premise in the argument that knowledge is inescapably doxastic. Logoi, because they are ‘propositions (or definitions) that describe [the world of the forms] as correctly as possible’, face the same problem as sense-perceptions – they are, T. claims, ‘affected by subjectivism’ (p. 43). The only further explanation provided on this point is that ‘propositions need judgement, and judgements cannot avoid being subjective’ (p. 43). Apparently, then, the subjectivity of judgement about what is true or false, of the sort involved in supplying a logos, opens epistêmê to the possibility of error. Epistêmê is doxastic and inherently fallible, then, because it inherits subjectivity from the logos requirement.

This is a novel and exciting interpretation; unfortunately, in its present form, it is thinly argued. Even if one grants the view that, for Plato, logoi are propositions which describe the world of the forms truly or falsely (a point about which there has been significant scholarly discussion) and therefore require judgement about what is true and false, one need not also grant that this sort of judgement is necessarily subjective in nature or that this subjectivity renders human knowledge fallible. One would certainly need reasons, beyond the interesting conclusions it produces, for attributing this rather idiosyncratic view to Plato.

Moreover, we have good textual reasons to doubt both that Platonic epistêmê is fallible and that the nature of logos is responsible. In fact, in passages such as Meno 98a and Republic 533b–d, Plato seems to hold the opposite view. Knowledge is famously more secure (μόνιμος) than true belief, in so far as it is accompanied by a logos (Meno 98a6). If this logos were subjective, and therefore the source of the inherent fallibility of human knowledge, it is hard to see why its presence would add to the surety of a true belief (rather than detract from it). Similarly, in the discussion of dialectic in Republic 7, Socrates describes the process by which seeking out explanations (logoi) for one's beliefs, might, after years of investigation, deliver a thinker to a first principle. Here dialectic is described as the only process that can arrive at such a principle, in such a way that it is secured or confirmed (ἵνα βεβαιώσηται) (533c5–d1). Although there is good reason to question whether Plato has in mind a coherentist or a foundationalist system of justification, this passage weighs heavily against both the fallibility of knowledge and the view that the subjectivity of logoi could be responsible for that fallibility. Not only is human knowledge, understanding with surety, possible as a result of the dialectical process, but logoi, the reasons or explanations which are essential to this process, are the very source of that security.

Much of this volume rests on an idiosyncratic understanding of Platonic logoi, which, although it produces very exciting results, including the view that human beings cannot have complete or secure understanding of the forms in this lifetime, is not adequately defended (especially in light of rather strong textual evidence for the standard or ‘dogmatic’ approach). An interesting and consistent theory of Platonic epistemology emerges from this work, which is both worthy of consideration and would, if it were correct, have profound consequences for how scholars read Plato, yet these conclusions depend on a premise that is unlikely to withstand scrutiny.