112. Essence is not distinguished from existence even in finite beings. It is a distinction in conceptions, to which there is no real distinction corresponding. 113. The identity of essence with existence does not involve the necessity of finite things. The arguments by which some pretend to establish this consequence are founded upon an ambiguous meaning of words. 114. Kant's opinion, which limits the idea of reality, and that also of negation, to the purely sensible order, would destroy all intelligence, since it overthrows the very principle of contradiction. This doctrine of the German philosopher is also in opposition with what he himself taught concerning purely intellectual conceptions, distinct from sensible representations. When he refers the ideas of reality and negation to that of time, as the primitive form of the inward sense, he leaves out of the idea of reality what no less pertains to it, and presents the idea of time under a point of view wholly equivocal. 115. As sensible representation is based upon the finite intuition of extension, so the perceptive faculties of the pure understanding receive the idea of being as their foundation. In the same manner that extension is presented to sensibility as limitable, and from limitability results figurability, and consequently all the objects of geometrical science; so also does the idea of not-being, combined with that of being, fecundate in a manner the metaphysical sciences. The parallelism of the two ideas, extension and being, is not of such a nature as to render the former independent of the latter. So far as science is concerned, the idea of extension is sterile, if it be not combined with the general idea of being and not-being. This may be shown in many ways; but it will suffice to recollect that geometry cannot take a single step without the principle of contradiction, into which the ideas of being and of not-being enter.[24] [24] See L. IV., C. V. 116. All our cognitions flow from the idea of being and not-being, combined with intuitive ideas. We shall have occasion in the following books to remark this admirable fecundity of an idea, which, although it cannot of itself teach any thing, can yet, when united with others, and modified itself in various ways, so illuminate the intellectual world as to merit to be called the object of understanding. BOOK SIXTH. UNITY AND NUMBER. CHAPTER I. PRELIMINARY CONSIDERATIONS ON THE IDEA OF UNITY. 1. Before analyzing the idea of number, let us examine its simplest element, unity. Number is a connection of unities. We cannot know what number is, if we do not know what unity is.[25] [25] See L. V., C. X.