so of fatigue, which they effect. Like all technical inventions, those products must be brought to the market; and the market alone decides upon their value and assigns to them their price. At the present time, it seems that logistic methods have no value and price, save for certain narrow circles of people, who amuse themselves with them in their own way and so pass the time. [Sidenote: _Erroneous separation of truth and reason of truth in the pure concepts._] Certain erroneous doctrines take their origin from the undue separation of demonstration and definition, conspicuously that particular error which places a difference of degree between _truth_ and _reason_ of truth, and consequently admits that a truth can be known without its reason being known. But a truth, of which the reason is not known, is not even truth; or it is truth only in preparation and in hypothesis. We hear much about the _intuition_ with which men of genius are equipped, and which enables them to go straight to the truth, even when they are not capable of demonstrating it. But this intuition, when it is not that truth in preparation, or that orientation towards a truth still quite hypothetical, must of necessity be thought and thus also be demonstration of truth; it must be truth and also reason of truth; thought and reasoning performed no doubt with lightning rapidity, which is expressed in brief propositions and needs going over again and rethinking, in order that it may afford a more ample and, from the didactic point of view, a more persuasive, exposition; but it is always thought and reasoning. Things are still worse, when not only is a diversity of degree admitted, but the complete _indifference_ of demonstration to truth is proclaimed, so that many or infinite possible demonstrations of one identical truth would be possible. If by this it were meant merely that one identical truth, or one identical concept, can assume infinite verbal or expressive forms, and if demonstration were understood as "exposition" or "expression," there would be nothing to object. But if by demonstration be meant something truly logical, that which is properly called by that name in Logic, this thesis leads directly to the negation of truth, making the demonstration of truth, or truth itself, an illusion, a sophistical appearance created simply to persuade. Those acquainted with courts of law know that very often when a magistrate has made his decision and pronounced sentence he deputes to a younger colleague the task of "reasoning" it, or of providing an appearance of reasoning to what is indeed not a logical product, but simply the _voluntas_ of a certain provision. But though this procedure be intelligible and useful when it occurs in the field of practice and of law, it cannot be admitted in the theoretical field, where it would be the ruin of thought and indirectly of the will itself. [Sidenote: _Difference between truth and reason of truth in the pseudoconcepts._]