222. What, then, shall we say of this proposition: "Whatever is evident is true?" It is not an axiom, for the predicate is not contained in the idea of the subject; it is not a demonstrable proposition, for all demonstration rests on evident principles, and consists in deducing from them a consequence evidently connected with them; this cannot take place unless we presuppose the legitimacy of evidence, that is to say, that which is the object of the demonstration. At the commencement of the argument, it might be asked, how do you know the principle on which your argument is based? How do you know it to be true? By evidence. But recollect you are proving that whatever is evident is true, and, therefore, you beg the question. The truth of the laws of logic, to which every argument must conform, is known only by evidence; therefore if we do not suppose whatever is evident to be true, we cannot argue at all. 223. We hold then that the principle of evidence can be based on no other principle, and that, consequently, it has the first mark of the fundamental principle. If it fails, all other principles,--that of contradiction, known like the others only by evidence, included,--fail with it; this is another mark of the fundamental principle. Let us see if it has the third, by aid of which, whoever denies the rest may be refuted. Rarely does any one deny the principle of contradiction, and admit that of evidence; yet, making this extravagant supposition, this principle alone would be of avail, because the question would be reduced to this: does he admit the principles to be evident? If he does not, his intellect is unlike that of other men; if he does, the argument brought against him is conclusive. You admit that whatever is evident is true; such or such a principle is evident for you, therefore it is true. The premises are evident of themselves; the legitimacy of the consequence is also evident; and he must consequently admit it, since he admits the criterion of evidence to be a general rule.