Theaetetus (170)

SOC. Let us then get the agreement in as concise a form as possible, not through others, but from his own statement.

THEO. How?

SOC. In this way: He says, does he not? that which appears to each person really is to him to whom it appears.

THEO. Yes, that is what he says.

SOC. Well then, Protagoras, we also utter the opinions of a man, or rather, of all men, and we say that there is no one who does not think himself wiser than others in some respects and others wiser than himself in other respects; for instance, in times of greatest danger, when people are distressed in war or by diseases or at sea, they regard their commanders as gods and expect them to be their saviors, though they excel them in nothing except knowledge. And all the world of men is, I dare say, full of people seeking teachers and rulers for themselves and the animals and for human activities, and, on the other hand, of people who consider themselves qualified to teach and qualified to rule. And in all these instances we must say that men themselves believe that wisdom and ignorance exist in the world of men, must we not?

THEO. Yes, we must.

SOC. And therefore they think that wisdom is true thinking and ignorance false opinion, do they not?

THEO. Of course.

SOC. Well then, Protagoras, what shall we do about the doctrine? Shall we say that the opinions which men have are always true, or sometimes true and sometimes false? For the result of either statement is that their opinions are not always true, but may be either true or false. Just think, Theodorus, would any follower of Protagoras, or you yourself care to contend that no person thinks that another is ignorant and has false opinions?

THEO. No, that is incredible, Socrates.

SOC. And yet this is the predicament to which the doctrine that man is the measure of all things inevitably leads.

THEO. How so?

SOC. When you have come to a decision in your own mind about something, and declare your opinion to me, this opinion is, according to his doctrine, true to you; let us grant that; but may not the rest of us sit in judgement on your decision, or do we always judge that your opinion is true? Do not myriads of men on each occasion oppose their opinions to yours, believing that your judgement and belief are false?

THEO. Yes, by Zeus, Socrates, countless myriads in truth, as Homer [*] says, and they give me all the trouble in the world.

SOC. Well then, shall we say that in such a case your opinion is true to you but false to the myriads?

THEO. That seems to be the inevitable deduction.