The Anonymous Commentary on Plato’s Theaetetus, written by a Middle Platonic author between c. 45 b.c. and a.d. 150, is the only surviving ancient commentary on this Platonic dialogue. At the center of the anonymous commentator’s interpretation of the Theaetetus stands the thesis that the dialogue is investigating a specific kind of knowledge, viz. the so-called “simple knowledge.” The present paper examines this central concept in the commentator’s epistemology by analyzing several passages from the commentary in which the “simple knowledge” and related concepts are discussed. This study reveals the following results: By the term “simple knowledge” the anonymous author designates the basic units of knowledge in sciences like geometry and music theory. The commentator concedes that the Theaetetus does not succeed in defining this kind of knowledge. But this does not pose a problem for the author since he is firmly convinced that Plato, when writing the Theaetetus, had already established a definition of “simple knowledge,” viz. in the famous passage Meno 98a where Socrates explains the difference between right opinion and knowledge. According to the commentator, the Theaetetus is moving slowly but steadily towards this definition, which is suppressed at the end of the dialogue only for didactical reasons. Remarkably, the commentator does not use the expression αἰτίας λογισμῷ (“by reasoning about the cause”) but αἰτίᾳ λογισμοῦ (“by the cause of reasoning”) when quoting the definition he extracts from Meno 98a. However, this difference does not seem to have any influence on his interpretation of the definition, since he argues that the definition amounts to the proposition that we know p when we know not only that p but also why p. Like the Platonic Socrates in Meno 98a, the commentator identifies the binding of right opinions with recollection, and accordingly he holds that “simple knowledge” is acquired by recollection. The epistemological prerequisite for acquiring “simple knowledge” through recollection are the so-called “natural notions” (φυσικαὶ ἔννοιαι), which the commentator (in Middle Platonic fashion) identifies with the memory traces resulting from the soul’s pre-carnate vision of the Forms. It is the task of the maieutic teacher to “unfold” and “articulate” these natural notions. When this is accomplished, the
The present paper investigates the question as to how and for what purposes the Middle Platonic author of the Anonymous Commentary on Plato’s Theaetetus uses Aristotelian and Stoic syllogistic in his interpretation of the Platonic text. This investigation shows that the commentator employs Aristotelian categorical syllogistic as an exegetical tool for reconstructing arguments in the Platonic text, enabling him not only to uncover doctrinal statements that are in his view hidden in the Platonic text, but also to dissociate Plato from unwelcome propositions. By contrast, the commentator uses Stoic hypothetical syllogistic as a polemical tool for constructing ad hominem arguments against the Stoics. More precisely, the author exploits the Stoic type of deductive reasoning to draw anti-Stoic conclusions from premises that are accepted by the Stoics, and in doing so, he manages not only to refute Stoic doctrines, but also to corroborate the corresponding Platonic theories.