I. Euclides was a native of Megara on the Isthmus, or of Gela, according to some writers, whose statement is mentioned by Alexander in his Successions. He devoted himself to the study of the writings of Parmenides; and his successors were called the philosophers of the Megaric school; after that they were called the Contentious school, and still later, the Dialecticians, which name was first given to them by Dionysius the Carthaginian; because they carried on their investigations by question and answer. Hermodorus says that after the death of Socrates, Plato and the other philosophers came to Euclides, because they feared the cruelty of the tyrants. II. He used to teach that the chief good is unity; but that it is known by several names; for at one time people call it prudence; at another time God; at another time intellect, and so on. But everything which was contrary to good, he discarded, denying its existence. And the proofs which he used to bring forward to support his arguments, were not those which proceed on assumptions, but on conclusions. He also rejected all that sort of reasoning which proceeds on comparison, saying that it must be founded either on things which are like, or on things which are unlike. If on things which are like, then it is better to reason about the things themselves, than about those which resemble them; and if on things which are unlike, then the comparison is quite useless. And on this account Timon uses the following language concerning him, where he also attacks all the other philosophers of the Socratic school:— But I do care for none of all these triflers, Nor for any one else; not for your Phædon, Whoever he may be; not for the quarrelsome Euclides, who bit all the Megareans With love of fierce contention. III. He wrote six dialogues—the Lamprias, the Æschines, the Phœnix, the Crito, the Alcibiades, and the Amatory dialogue. IV. Next in succession to Euclides, came Eubulides of Miletus, who handed down a great many arguments in dialectics; such as the Lying one; the Concealed one; the Electra; the Veiled one; the Sorites; the Horned one; the Bald one.[26] And one of the Comic poets speaks of him in the following terms:— Eubulides, that most contentious sophist, Asking his horned quibbles, and perplexing The natives with his false arrogant speeches, Has gone with all the fluency of Demosthenes. For it seems that Demosthenes had been his pupil, and that being at first unable to pronounce the R, he got rid of that defect. Eubulides had a quarrel with Aristotle, and was constantly attacking him.