Page:Ferrier's Works Volume 1 - Institutes of Metaphysic (1875 ed.).djvu/102

74 there is such a point, is proved by the fact that such a point has been found.

§ 84. The common point, or quality, or feature in all our knowledge must be such an element as is necessary or essential to the constitution of every datum of cognition. In other words, it must be such an element that, if taken away, the whole datum is, of necessity, extinguished, and its restoration rendered absolutely impossible until the missing element is restored. The element which we must find as a reply to the first question of philosophy must be of this character, otherwise it would not answer the purposes of a strictly-reasoned scheme: it would not be the one point present in every cognition. Experience may confirm the truth of the answer; but Reason alone can establish it effectually.

§ 85. To re-state, then, the fundamental or proximate question of philosophy, it is this—What is the one feature which is identical, invariable, and essential in all the varieties of our knowledge? What is the standard factor which never varies while all else varies? What is the ens unum in omnibus notitiis?