I wish to thank Lloyd Gerson for having read and reviewed my book: the purpose of publishing it in English was precisely to elicit discussion.
In his first objection, Gerson disputes my idea that, after the Republic, the Theaetetus practically starts anew (or, rather, from the simple condition that the episteme sought for must be infallible). According to Gerson, from 152c5-6 it may be inferred that in the Theaetetus Plato also sets out from the fact that all knowledge is knowledge of something that is—a reference to Resp. 477a-478d. So the Theaetetus would actually be setting out from the Republic. But if Plato in the Theaetetus really were setting out from the Republic, it would be difficult to understand why the dialogue takes into consideration, as definitions of knowledge, theses focusing on sense-perception and doxa, which the Republic had already discarded. We would rather expect the Theaetetus to set out from an analysis of noesis. Nor does passage 152c5-6 prove that this is not the case. Probably, in stating that knowledge is always knowledge of what is, Plato is alluding to the fact that the sought for episteme only concerns the forms. But this is what the enquiry is meant to show, not the premise from which it sets out. If Plato had already established at 152c5-6 that doxa (belief) cannot coincide with knowledge because its object is what is and is not, why would he want to take into consideration the second and third definitions of episteme, where knowledge is identified with a certain kind of doxa (belief)?
As far as fallible knowledge is concerned, I would not reduce this to a matter of names: if one decides to call only infallible knowledge knowledge, then fallible knowledge of the forms is not really knowledge at all; but one may also choose—as, in my view, Plato does—to use the word knowledge/episteme on different levels, and even in relation to sensible objects. In this case, knowledge of the forms, which is fallible even though it is supported by logos, is obviously also knowledge, insofar as it is the highest kind of knowledge that we have. So when we speak of knowledge, it is necessary to clarify what kind of knowledge it is.
In other words, while it is true (I quote) that there can be no infallible knowledge of anything other than that which is, it is not true that cognition of that which is can only be infallible. For it is possible to have a knowledge of what is that is approximate, fallible, incomplete and provisional—the forms being that which is in the strong sense for Plato. Between not knowing justice, for instance, and knowing it infallibly there is the middle ground of a good, likely, well-founded yet not infallible knowledge: a knowledge whose object is the intelligible and not the sensible (hence the reference to sense perception, which Gerson associates with Philo of Larissa, is quite inappropriate).
This type of knowledge—and I here come to the third point—is exactly the kind of knowledge that one would expect to be assigned to man by a philosopher for whom μάθησις is ἀνάμνησις (Meno 81e; Phaedo 72e). Gerson argues that the Timaeus, Symposium and Republic negate the idea that our inability to recall is endemic to man's embodied state. But this cannot be the case, since none of the three dialogues state that μάθησις is ἀνάμνησις. Nor is it true that I have attributed to the soul an endemic incapacity to recall. Rather, what I have argued is that this recollection will never be a form of knowledge on a par with the direct and actual knowledge of the forms attributed to the disembodied soul (which is infallible, as it a species in an Incorrigible Mental State). This is quite obvious: one doesn't need to be a psychologist to acknowledge that recollection is endemically fallible, and that therefore the kind of knowledge that coincides with recollection cannot be the infallible knowledge that is sought for in the Theatetus. Besides, this dialogue makes repeated allusions to the fallibility of recollection (e.g. the wax tablet, the aviary, the tribunal).
Let us turn now to some more specific points (I am particularly concerned by the methodological observations made):
1. Gerson explicitly claims that the difference between philosophers and philodoxers presented in the Republic disproves my interpretation of the Theaetetus. This may well be. But before making such a bold statement, Gerson ought to have at least attempted to refute the long section of the book (pp. 159-164) where I set out to show that the distinction between philosophers and philodoxers does not disprove, but rather confirms, my interpretation of Platonic epistemology.
2. Gerson argues that on the basis of an unspecified claim made by Socrates in the Phaedo (what he claims is stated on the Phaedo) I arbitrarily conclude that it is impossible for embodied people to attain knowledge. In order for the reader to get an idea of whether or not this is my own personal interpretation, I will reveal what passage we are talking about and quote the most significant lines from it: καὶ τότε, ὡς ἔοικεν, ἡμῖν ἔσται οὗ ἐπιθυμοῦμέν τε καί φαμεν ἐρασταὶ εἶναι, φρονήσεως, ἐπειδὰν τελευτήσωμεν, ὡς ὁ λόγος σημαίνει, ζῶσιν δὲ οὔ. εἰ γὰρ μὴ οἷόν τε μετὰ τοῦ σώματος μηδὲν καθαρῶς γνῶναι, δυοῖν θάτερον, ἢ οὐδαμοῦ ἔστιν κτήσασθαι τὸ εἰδέναι ἢ τελευτήσασιν (66e). My interpretation of this passage, Gerson argues, stands in contrast to what we read in other Platonic passages in the Timaeus, Symposium and Republic. This may be the case. But Gerson himself admits that I do not scruple to use these dialogues to support my interpretation. What this means is that I have sought to offer an explanation that takes account of all the dialogues in question. Of course, my interpretation may be wrong. But in order to claim this, Gerson ought first to have discussed it, something I cannot do with Gerson's own thesis, since he does not tell us how he interprets Phaedo 66c-e (given that he finds my interpretation unconvincing).
3. Gerson writes: There are no grounds for asserting, as Trabattoni does, that here Plato introduces a new sense of belief according to which the internal problems of belief as knowledge based on sense-perception are avoided. There is nothing in the text to support this conjecture. Yet in Tht. 187a Socrates announces that henceforth, leaving sense-perception (aisthesis) aside, they will be focusing on the soul's activity: ὅτι ποτ᾽ ἔχει ἡ ψυχή, ὅταν αὐτὴ καθ᾽ αὑτὴν πραγματεύηται περὶ τὰ ὄντα. Theaetetus replies that this activity is called δοξάζειν, and Socrates agrees: ὀρθῶς γὰρ οἴει, ὦ φίλε. To take another example, according to Gerson what is the meaning of the word δοξάζειν in the passage from the Republic (413a7-8)—repeatedly quoted in my book—which states τὸ τὰ ὄντα δοξάζειν ἀληθεύειν δοκεῖ σοι εἶναι;? And what does doxa mean in Sophist 264a2 (ὅταν οὖν τοῦτο ἐν ψυχῇ κατὰ διάνοιαν ἐγγίγνηται μετὰ σιγῆς, πλὴν δόξης ἔχεις ὅτι προσείπῃς αὐτό;)? Or in Philebus 38e (καὶ λόγος δὴ γέγονεν οὕτως ὃ τότε δόξαν ἐκαλοῦμεν)? Is it not the case that what is being discussed here is a belief/doxa that has nothing to do with the problems related to sense-perception, but which is closely bound to thought and being? Be that as it may, my interpretation of that passage of the Theaetetus (or indeed others) might be wrong. But if Gerson wishes to argue that there are no passages that support my hypothesis, he first ought to refute these interpretations.
4. Gerson writes: Timaeus 51E3-4 which says that true belief has no logos must count as a rejection by Plato of the view that Trabattoni thinks Plato is concealing in Theaetetus. Really? In Tht. 190a5 we read τὸ δοξάζειν λέγειν καλῶ καὶ τὴν δόξαν λόγον εἰρημένον (but see, of course, also the passages quoted under point 3). How can something which is logos not have logos? Why should we use the Timaeus to refute what is expressly stated in the Theaetetus? Rather, we are required to find a sense of doxa/doxazein in Plato compatible with the fact that there is a doxazein of being (Resp. 413a7-8; Tht. 187a), that there is a doxa that is dianoia (Soph. 264a2) and logos (Tht. 190a5; Phil. 38e2-3).
5. Gerson states that for Plato knowing a Form is a mental seeing of it, as though this were an established fact, and brings up this point as proof against my interpretation. But why does he not take account of what I state in relation to this in many sections of the book? I too believe that in order to have an opinion about a certain thing, it is necessary to have seen it. Indeed, the soul has seen the ideas before becoming embodied. But as it no longer sees them now, it is forced to keep to its thoughts/recollections/opinions.
More generally, any reader of Plato will see that there are some passages in the dialogues that present a stronger and more confident epistemology, and others that present an apparently weaker and more cautious one. Frankly, I find it rather pointless to simply set the two in contrast (or, worse still, to overlook some passages while quoting others). Probably intending this as a criticism, Gerson writes that I do not scruple to use in support of my theses passages that have mostly been adduced as evidence to the contrary. Well, I take this criticism as a compliment: in my view, the interpreter's task is precisely to find an overall explanation that, within reasonable limits, takes account of all the available data.
Finally, Gerson complains about the quality of the translation, stating that, aside from certain (rather questionable) infelicities, There are also many places in which the translator does not seem to grasp the subtle distinctions Trabattoni is making. However, he fails to quote actual examples of this misunderstanding of the Italian.