 Socrates, it should be kept in mind, does not appear in all of Plato’s works. He makes no appearance in Laws, and there are several dialogues (Sophist, Statesman, Timaeus) in which his role is small and peripheral, while some other figure dominates the conversation or even, as in the Timaeus and Critias, presents a long and elaborate, continuous discourse of their own. Plato’s dialogues are not a static literary form; not only do his topics vary, not only do his speakers vary, but the role played by questions and answers is never the same from one dialogue to another. (Symposium, for example, is a series of speeches, and there are also lengthy speeches in Apology, Menexenus, Protagoras, Crito, Phaedrus, Timaeus, and Critias; in fact, one might reasonably question whether these works are properly called dialogues). But even though Plato constantly adapted “the dialogue form” (a commonly used term, and convenient enough, so long as we do not think of it as an unvarying unity) to suit his purposes, it is striking that throughout his career as a writer he never engaged in a form of composition that was widely used in his time and was soon to become the standard mode of philosophical address: Plato never became a writer of philosophical treatises, even though the writing of treatises (for example, on rhetoric, medicine, and geometry) was a common practice among his predecessors and contemporaries. (The closest we come to an exception to this generalization is the seventh letter, which contains a brief section in which the author, Plato or someone pretending to be him, commits himself to several philosophical points—while insisting, at the same time, that no philosopher will write about the deepest matters, but will communicate his thoughts only in private discussion with selected individuals. As noted above, the authenticity of Plato’s letters is a matter of great controversy; and in any case, the author of the seventh letter declares his opposition to the writing of philosophical books. Whether Plato wrote it or not, it cannot be regarded as a philosophical treatise, and its author did not wish it to be so regarded.) In all of his writings—except in the letters, if any of them are genuine—Plato never speaks to his audience directly (see Frede 1992) and in his own voice. Strictly speaking, he does not himself affirm anything in his dialogues; rather, it is the interlocutors in his dialogues who are made by Plato to do all of the affirming, doubting, questioning, arguing, and so on. Whatever he wishes to communicate to us is conveyed indirectly.