pg. 6 About the gods, I have no means of knowing either that they exist or that they do not exist. - Hesychius of Alexandria, as quoted in Scholia on Plato, Republic 600C
pg. 9 Even though his sons were fine young men and died within seven days of each other, he endured it free from grief; for he maintained his calm, and this brought him great benefits every day, in terms of happiness, freedom from pain and good reputation amongst the multitude. For every man who saw Pericles bearing his sorrows in so steadfast a way thought that he was both high-minded and brave, and even more powerful than themselves, knowing very well that they themselves would be helpless in such circumstances. - Pseudo-Plutarch, Consolation to Apollonius 118EF = 80B9
pg. 10 Man is the measure of all things, of those which are, that they are, and of those which are not, that they are not. - Plato, Theaetetus
pg. 12 that each of us is the measure of the things that are and those which are not, although one man differs vastly from another for this very reason: because, for one man, certain things are and appear to be, while for another man, other things do. I am far from denying that wisdom and the wise man exist; but I do claim that the wise man is as follows: anyone who, when bad things appear to be and are for one of us, could change things around to make them both appear to be and be good. - Plato, Theaetetus
pg. 12 So, just as was said earlier, remember that for the invalid the things he eats appear to be, and are, bitter, while for the healthy man they are, and appear to be, the opposite. Well, we mustn't reckon either of them wiser - for that's not possible - nor must we accuse the man who is ill of being ignorant for believing such things, whereas the healthy man is wise because he has alternative beliefs. Instead, we must change one to the other, given that the latter condition is better So, in education as well, we must bring about a change from one condition to a better one; and while the doctor makes changes with drugs, the sophist does this with words. - Plato, Theaetetus
pg. 12 I, on the other hand, call some things better than others, but in no way truer. - Plato, Theaetetus
pg. 13 And men, he says, apprehend different things at different times in accordance with their differing dispositions; for he who is in a natural state apprehends those things in matter which are able to appear to those in a natural state, and those who are in a state contrary to nature the things that appear to those in an unnatural state. Furthermore, just the same account applies to the different stages of life, and to people according as they are asleep or awake, and to each distinct kind of condition. Thus, according to him, man becomes the criterion of what is the case; for all things that appear to men also are the case, and things that appear to no man are conversely not the case. - Sextus Empiricus, Outlines of Pyrrhonism I 216-19 = A14
pg. 14 Man is the measure of all things, of things that are that they are, and of things that are not that they are not.' And to the truth of this even the opposite assertion seems to testify; for if anyone claims that man is not the criterion for all things, he will simply be confirming the statement that man is the criterion, since the very person who is making the claim is himself a man, and in affirming what appears to him to be the case, he admits that this very claim is one of the things that appears to him. - Sextus Empiricus, Against the Mathematicians VII 60-64
pg. 14 In view of the fact, then, that no impression is received independent of circumstances, each man must be trusted in respect of those received in his own circumstances. - Sextus Empiricus, Against the Mathematicians VII 60-64
pg. 16 And the good is something so varying and manifold, that this particular thing is good for men's bodies, externally, while, internally, the very same thing is extremely bad. - Plato, Protagoras
pg. 21 Concerning the gods, I am not in a position to know either that they exist, or that they do not exist; for there are many obstacles in the way of such knowledge, notably the intrinsic obscurity of the subject and the shortness of human life. - Diogenes Laertius
pg. 24 Then, through his ... they're young. pg. 32
pg. 32 Teaching requires natural ability and practice. - Anecdota Parisiensia I 171,31
In learning, one must start from early youth. - Anecdota Parisiensia I 171,31
pg. 33 So, first of all, ... moderate length.
pg. 34 Now, how will we talk about Polus's school of speech and how he teaches how to say things twice (diplasiolgia) and as maxims (gnomologia) and as images (eikonologia); and about his Licymnian words, which that man gave him to help acheive eloquence? - Plato, Phaedrus
pg. 35 and this man ... has been said?
pg. 37 'I think,' he said, 'Socrates, that the most important part of a man's education is to become skilled in verse: that is to be able to understand the words of the poets, what has been composed correctly and incorrectly; and to know how to distinguish this and give an account of it if one is asked. - Plato, Protagoras
pg. 39 Should Hippocrates come to me, he won't experience the type of things he would experience if he associated with some other sophist. For those others maltreat the young and they drive those who have fled from the arts back again against their will, as they involve them in the arts, teaching them arithmetic and astronomy and geometry and music.'(And as he said this he glanced at Hippias.) 'By contrast, whoever comes to me will learn nothing other than that for the sake of which he has come. This learning constitutes good management in one's own affairs, so that he can run his house excellently and also, concerning the city, so that he becomes very capable of acting and speaking with regard to civic matters. - Plato, Protagoras
Diogenes Laertius, Book IX - Protagoras
51. Protagoras was the first to maintain that there are two sides to every question, opposed to each other, and he even argued in this fashion, being the first to do so. Furthermore he began a work thus: "Man is the measure of all things, of things that are that they are, and of things that are not that they are not." He used to say that soul was nothing apart from the senses, as we learn from Plato in the Theaetetus, and that everything is true. In another work he began thus: "As to the gods, I have no means of knowing either that they exist or that they do not exist. For many are the obstacles that impede knowledge, both the obscurity of the question and the shortness of human life." 52. For this introduction to his book the Athenians expelled him; and they burnt his works in the market-place, after sending round a herald to collect them from all who had copies in their possession.
He was the first to exact a fee of a hundred minae and the first to distinguish the tenses of verbs, to emphasize the importance of seizing the right moment, to institute contests in debating, and to teach rival pleaders the tricks of their trade. Furthermore, in his dialectic he neglected the meaning in favour of verbal quibbling, and he was the father of the whole tribe of eristical disputants now so much in evidence; insomuch that Timon too speaks of him as
Protagoras, all mankind's epitome, Cunning, I trow, to war with words.
53. He too first introduced the method of discussion which is called Socratic. Again, as we learn from Plato in the Euthydemus, he was the first to use in discussion the argument of Antisthenes which strives to prove that contradiction is impossible, and the first to point out how to attack and refute any proposition laid down: so Artemidorus the dialectician in his treatise In Reply to Chrysippus. He too invented the shoulder-pad on which porters carry their burdens, so we are told by Aristotle in his treatise On Education; for he himself had been a porter, says Epicurus somewhere. This was how he was taken up by Democritus, who saw how skilfully his bundles of wood were tied. He was the first to mark off the parts of discourse into four, namely, wish, question, answer, command; 54. others divide into seven parts, narration, question, answer, command, rehearsal, wish, summoning; these he called the basic forms of speech. Alcidamas made discourse fourfold, affirmation, negation, question, address.
The story is told that once, when he asked Euathlus his disciple for his fee, the latter replied, "But I have not won a case yet." "Nay," said Protagoras, "if I win this case against you I must have the fee, for winning it; if you win, I must have it, because you win it."