[64] Plato, Theætêt. p. 161 D. ὁ δ’ ἄρα ἐτύγχανεν ὢν εἰς φρόνησιν οὐδὲν βελτίων βατράχου γυρίνου, μὴ ὅτι ἄλλου του ἀνθρώπων. I substitute the dog or horse as illustrations.
Belief on authority is true to the believer himself — The efficacy of authority resides in the believer’s own mind.
Belief on authority is true to the believer himself, like all his other beliefs, according to the Protagorean doctrine: and in acting upon it, — in following the guidance of A, and not following the guidance of B, — he is still a measure to himself. It is not to be supposed that Protagoras ever admitted all men to be equally wise, though Plato puts such an admission into his mouth as an inference undeniable and obvious. His doctrine affirms something altogether different:— that whether you believe yourself to be wise or unwise, in either case the belief is equally your own — equally the result of your own mental condition and predisposition, — equally true to yourself, — and equally an item among the determining conditions of your actions. That the beliefs and convictions of one person might be modified by another, was a principle held by Protagoras not less than by Sokrates: the former employed as his modifying instrument, eloquent lecturing — the latter, dialectical cross-examination. Both of them recognise the belief of the person to whom they address themselves as true to him, yet at the same time as something which may be modified and corrected, by appealing to what they thought the better parts of it against the worse.
Protagorean formula — is false, to those who dissent from it.
Again — Sokrates imputes it as a contradiction to Protagoras — “Your doctrine is pronounced to be false by many persons: but you admit that the belief of all persons is true: therefore your doctrine is false”.[65] Here also Plato omits the qualification annexed by Protagoras to his general principle — Every man’s belief is true — that is, true to him. That a belief should be true, to one man, and false to another — is not only no contradiction to the formula of Protagoras, but is the very state of things which his formula contemplates. He of course could only proclaim it as true to himself. It is the express purpose of his doctrine to disallow the absolutely true and the absolutely false. His own formula, like every other opinion, is false to those who dissent from it: but it is not false absolutely, any more than any other doctrine. Plato therefore does not make out his charge of contradiction.
[65] Plato, Theætêt. p. 171 A. Sextus Empiric. (adv. Mathem. vii. 61) gives a pertinent answer to this objection.
Plato’s argument — That the wise man alone is a measure — Reply to it.
Some men (says Sokrates) have learnt, — have bestowed study on special matters, — have made themselves wise upon those matters. Others have not done the like, but remain ignorant. It is the wise man only who is a measure: the ignorant man neither is so, nor believes himself to be so, but seeks guidance from the wise.[66]
[66] Plato, Theætêt. pp. 171 C, 179 B.
Upon this we may remark — First, that even when the untaught men are all put aside, and the erudites or Experts remain alone — still these very erudites or Experts, the men of special study, are perpetually differing among themselves; so that we cannot recognise one as a measure, without repudiating the authority of the rest.[67] If by a measure, Plato means an infallible measure, he will not find it in this way: he is as far from the absolute as before. Next, it is perfectly correct that if any man be known to have studied or acquired experience on special matters, his opinion obtains an authority with others (more or fewer), such as the opinion of an ignorant man will not possess. This is a real difference between the graduated man and the non-graduated. But it is a difference not contradicting the theory of Protagoras; who did not affirm that every man’s opinion was equally trustworthy in the estimation of others, but that every man’s opinion was alike a measure to the man himself. The authority of the guide resides in the belief and opinion of those who follow him, or who feel prepared to follow him if necessity arises. A man gone astray on his journey, asks the way to his destination from residents whom he believes to know it, just as he might look at a compass, or at the stars, if no other persons were near. In following their direction, he is acting on his own belief, that he himself is ignorant on the point in question and that they know. He is a measure to himself, both of the extent of his own ignorance, and of the extent of his own knowledge. And in this respect all are alike — every man, woman, child, and animal;[68] though they are by no means alike in the estimation of others, as trustworthy authorities.