"However strongly a thing may be believed, the degree of belief is no criterion of its truth." But what is truth? Perhaps it is a form of faith, which has become a condition of existence? Then _strength_ would certainly be a criterion; for instance, in regard to causality. 533. Logical accuracy, transparency, considered as the criterion of truth ("_omne illud verum est, quod clare et distincte percipitur._"--Descartes): by this means the mechanical hypothesis of the world becomes desirable and credible. But this is gross confusion: like _simplex sigillum veri._ Whence comes the knowledge that the real nature of things stands in _this_ relation to our intellect? Could it not be otherwise? Could it not be this, that the hypothesis which gives the intellect the greatest feeling of power and security, is _preferred, valued,_ and marked as _true_--The intellect sets its _freest_ and _strongest faculty_ and _ability_ as the criterion of what is most valuable, consequently of what is _true...._ "True"--from the standpoint of sentiment--is that which most provokes sentiment ("I"); from the standpoint of thought--is that which gives thought the greatest sensation of strength; from the standpoint of touch, sight, and hearing--is that which calls forth the greatest resistance. Thus it is the _highest degrees of activity_ which awaken belief in regard to the _object_, in regard to its "reality." The sensations of strength, struggle, and resistance convince the subject that there is something which is being resisted. 534. The criterion of truth lies in the enhancement of the feeling of power. 535. According to my way of thinking, "truth" does not necessarily mean the opposite of error, but, in the most fundamental cases, merely the relation of different errors to each other: thus one error might be older, deeper than another, perhaps altogether ineradicable, one without which organic creatures like ourselves could not exist; whereas other errors might not tyrannise over us to that extent as conditions of existence, but when measured according to the standard of those other "tyrants," could even be laid aside and "refuted." Why should an irrefutable assumption necessarily be "true"? This question may exasperate the logicians who limit _things_ according to the limitations they find in themselves: but I have long since declared war with this logician's optimism. 536. Everything simple is simply imaginary, but not "true." That which is real and true is, however, neither a unity nor reducible to a unity. 537. _What is truth?_--Inertia; _that_ hypothesis which brings satisfaction, the smallest expense of intellectual strength, etc. 538. First proposition. The _easier_ way of thinking always triumphs over the more difficult way;--_dogmatically_: _simplex sigillum veri_.--_Dico_: to suppose that _clearness_ is any proof of truth, is absolute childishness. . . .