But we are not unaware that some writers distinguish the various dialogues in a different manner from what we do. For they say that some of them are dramatic, and others narrative, and others of a mixed nature. But they, in this division, are classifying the dialogues in a theatrical rather than in a philosophical manner. Some of the dialogues also refer to subjects of natural philosophy, such as the Timæus. Of the logical class, there are the Politics, the Cratylus, the Parmenides, and the Sophist. Of the ethical kind there is the defence of Socrates, the Crito, the Phædo, the Phædrus, the Banquet, the Menexenus, the Clitophon, the Epistles, the Philebus, the Hipparchus, and the Rival Lovers. Of the political class there is the Republic, the Laws, the Minos, the Epinomis, and the Atlanticus. Of the midwife description we have the two Alcibiades’s, the Theages, the Lysis, the Laches. Of the tentative kind, there is the Euthyphro, the Meno, the Ion, the Charmides, and the Theætetus. Of the demonstrative description, we have the Protagoras, and of the distinctive class the Euthydemus, the two Hippias’s, and the Gorgias. And this is enough to say about the dialogues as to what they are, and what their different kinds are. XXXIII. But since there is also a great division of opinion respecting them, from some people asserting that in them Plato dogmatizes in a positive manner, while others deny this, we had better also touch upon this part of the question. Now, dogmatizing is laying down dogmas, just as legislating is making laws. But the word dogma is used in two senses; to mean both that which we think, and opinion itself. Now of these, that which we think is the proposition, and opinion is the conception by which we entertain it in our minds. Plato then explains the opinions which he entertains himself, and refutes false ones; and about doubtful matters he suspends his judgment. His opinions of matters as they appear to him he puts into the mouth of four persons, Socrates, Timæus, an Athenian poet, and an Eleatic stranger. But the strangers are not, as some people have supposed, Plato and Parmenides, but certain nameless imaginary characters. Since Plato asserts as undeniable axioms all the opinions which he puts into the mouth of Socrates or Timæus. But when he is refuting false propositions, he introduces such characters as Thrasymachus, and Callicles, and Polus, and Gorgias, and Protagoras, Hippias too, and Euthydemus, and men of that stamp. But when he is demonstrating anything, then he chiefly uses the inductive form of argument, and that too not of one kind only, but of two. For induction is an argument, which by means of some admitted truths establishes naturally other truths which resemble them. But there are two kinds of induction; the one proceeding from contraries, the other from consequents. Now, the one which proceeds from contraries, is one in which from the answer given, whatever that answer may be, the contrary of the principle