To this theory Plato imputes as a farther consequence, that it equalises all men and all animals. No doubt, the measure or limit as generically described, bears alike upon all: but it does not mark the same degree in all. Each man's bodily efforts are measured or limited by the amount of his physical force: this is alike true of all men: yet it does not follow that the physical force of all men is equal. The dog, the horse, the new-born child, the lunatic, is each a measure of truth to himself: the philosopher is so also to himself: this is alike true, whatever may be the disparity of intelligence: and is rather more obviously true when the disparity is great, because the lower intelligence has then a very narrow stock of beliefs, and is little modifiable by the higher. But though the Protagorean doctrine declares the dog or the child to be a measure of truth--each to himself--it does not declare either of them to be a measure of truth to me, to you, or to any ordinary by-stander. How far any person is a measure of truth to others, depends upon the estimation in which he is held by others: upon the belief which they entertain respecting his character or competence. Here is a new element let in, of which Plato, in his objection to the Protagorean doctrine, takes no account. When he affirms that Protagoras by his equalising doctrine acknowledged himself to be no better in point of wisdom and judgment than a dog or a child, this inference must be denied.[64] The Protagorean doctrine is perfectly consistent with great diversities of knowledge, intellect, emotion, and character, between one man and another. Such diversities are recognised in individual belief and estimation, and are thus comprehended in the doctrine. Nor does Protagoras deny that men are teachable and modifiable. The scholar after being taught will hold beliefs different from those which he held before. Protagoras professed to know more than others, and to teach them: others on their side also believed that he knew more than they, and came to learn it. Such belief on both sides, noway contradicts the general doctrine here under discussion. What the scholar believes to be true, is still true to him: among those things which he believes to be true, one is, that the master knows more than he: in coming to be taught, he acts upon his own conviction. To say that a man is wise, is to say, that he is wise _in some one's estimation_: your own or that of some one else. Such estimation is always implied, though often omitted in terms. Plato remarks very truly, that every one believes some others to be on certain matters wiser than himself. In other words, what is called authority--that predisposition to assent, with which we hear the statements and opinions delivered by some other persons--is one of the most operative causes in determining human belief. The circumstances of life are such as to generate this predisposition in every one's