No one before this serious thinker had ever doubted what follows. First, and before all things in heaven and on earth, is the Principle of Sufficient Reason in the form of the Law of Causality. For it is a _veritas æterna_: _i.e._ it is in and by itself above Gods and Fate; whereas everything else, the understanding, for instance, which thinks that principle, and no less the whole world and whatever may be its cause--atoms, motion, a Creator, _et cætera_--is what it is only in accordance with, and by virtue of, that principle. Hume was the first to whom it occurred to inquire whence this law of causality derives its authority, and to demand its credentials. Everyone knows the result at which he arrives: that causality is nothing beyond the empirically perceived succession of things and states in Time, with which habit has made us familiar. The fallacy of this result is felt at once, nor is it difficult to refute. The merit lies in the question itself; for it became the impulse and starting-point for Kant's profound researches, and by their means led to an incomparably deeper and more thorough view of Idealism than the one which had hitherto existed, and which was chiefly Berkeley's. It led to transcendental Idealism, from which arises the conviction, that the world is as dependent upon us, as a whole, as we are dependent upon it in detail. For, by pointing out the existence of those transcendental principles, as such, which enable us to determine _à priori_, _i.e._ before all experience, certain points concerning objects and their possibility, he proved that these things could not exist, as they present themselves to us, independently of our knowledge. The resemblance between a world such as this and a dream, is obvious. § 13. _Kant and his School._ Kant's chief passage on the Principle of Sufficient Reason is in a little work entitled "On a discovery, which is to permit us to dispense with all Criticism of Pure Reason."[44] Section I., _lit._ A. Here he strongly urges the distinction between "the logical (formal) principle of cognition 'every proposition must have its reason,' and the transcendental (material) principle 'every thing must have its cause,'" in his controversy with Eberhard, who had identified them as one and the same.--I intend myself to criticize Kant's proof of the _à priori_ and consequently transcendental character of the law of causality further on in a separate paragraph, after having given the only true proof. [44] "Ueber eine Entdeckung, nach der alle Kritik der reinen Vernunft entbehrlich gemacht werden soll."