A similar remark may be made as to Plato's distinction between the different matters to which belief may apply: present sensation or sentiment in one case--anticipation of future sensations or sentiments, in another. Upon matters of present sensation and sentiment (he argues), such as hot or cold, sweet or bitter, just or unjust, honourable or base, &c., one man is as good a judge as another: but upon matters involving future contingency, such as what is healthy or unhealthy,--profitable and good, or hurtful and bad,--most men judge badly: only a few persons, possessed of special skill and knowledge, judge well, each in his respective province. [Side-note: The formula of Relativity does not imply that every man believes himself to be infallible.] I for my part admit this distinction to be real and important. Most other persons admit the same.[69] In acting upon it, I follow out my belief,--and so do they. This is a general fact, respecting the circumstances which determine individual belief. Like all other causes of belief, it operates relatively to the individual mind, and thus falls under that general canon of relativity, which it is the express purpose of the Protagorean formula to affirm. Sokrates impugns the formula of relativity, as if it proclaimed every one to believe himself more competent to predict the future than any other person. But no such assumption is implied in it. To say that a man is a measure to himself, is not to say that he is, or, that he believes himself to be, omniscient or infallible. A sick man may mistake the road towards future health, in many different directions. One patient may over-estimate his own knowledge,--that is one way, but only one among several: another may be diffident, and may undervalue his own knowledge: a third may over-estimate the knowledge of his professional adviser, and thus follow an ignorant physician, believing him to be instructed and competent: a fourth, instead of consulting a physician, may consult a prophet, whom Plato[70] here reckons among the authoritative infallible measures in respect to future events: a fifth may (like the rhetor Ælius Aristeides[71]) disregard the advice of physicians, and follow prescriptions enjoined to him in his own dreams, believing them to be sent by Æsculapius the Preserving God. Each of these persons judges differently about the road to future health: but each is alike a measure to himself: the belief of each is relative to his own mental condition and predispositions. You, or I, may believe that one or other of them is mistaken: but here another measure is introduced--_your_ mind or _mine_. [Footnote 69: Plato, Theætêt. p. 179 A. [Greek: pa=s a)\n o(mologoi=].] [Footnote 70: Plato, Theætêt. p. 179 A, where Mr. Campbell observes in his note--"The [Greek: ma/ntis] is introduced as being [Greek: e)pistê/môn] of the future generally; just as the physician is of future health and disease, the musician of future harmony," &c.]