The following is my objection against this promiscuous employment of the word _ground_ (reason) and, with it, of the Principle of Sufficient Reason in general; it is likewise the second result, intimately connected with the first, which the present treatise gives concerning its subject-matter proper. The four laws of our cognitive faculty, of which the Principle of Sufficient Reason is the common expression, by their common character as well as by the fact that all Objects for the Subject are divided amongst them, proclaim themselves to be posited by one and the same primary quality and inner peculiarity of our knowing faculty, which faculty manifests itself as Sensibility, Understanding, and Reason. Therefore, even if we imagined it to be possible for a new Fifth Class of Objects to come about, we should in that case likewise have to assume that the Principle of Sufficient Reason would appear in this class also under a different form. Notwithstanding all this, we still have no right to talk of an _absolute reason_ (ground), nor does a _reason in general_, any more than a _triangle in general_, exist otherwise than as a conception derived by means of discursive reflection, nor is this conception, as a representation drawn from other representations, anything more than a means of thinking several things in one. Now, just as every triangle must be either acute-angled, right-angled, or obtuse-angled, and either equilateral, isosceles or scalene, so also must every reason belong to one or other of the four possible kinds of reasons I have pointed out. Moreover, since we have only four well-distinguished Classes of Objects, every reason must also belong to one or other of these four, and no further Class being possible, Reason itself is forced to rank it within them; for as soon as we employ a reason, we presuppose the Four Classes as well as the faculty of representing (_i.e._ the whole world), and must hold ourselves within these bounds, never transcending them. Should others, however, see this in a different light and opine that a _reason in general_ is anything but a conception, derived from the four kinds of reasons, which expresses what they all have in common, we might revive the controversy of the Realists and Nominalists, and then I should side with the latter. ON THE WILL IN NATURE. AN ACCOUNT OF THE CORROBORATIONS RECEIVED BY THE AUTHOR'S PHILOSOPHY SINCE ITS FIRST APPEARANCE FROM THE EMPIRICAL SCIENCES. BY ARTHUR SCHOPENHAUER. _Translated from the Fourth Edition published by_ JULIUS FRAUENSTÄDT. Τοιαῦτ' ἐμοῦ λόγοισιν ἐξηγουμένου, Οὐκ ἠξίωσαν οὐδὲ προσβλέψαι τὸ πᾶν· Ἀλλ' ἐκδιδάσκει πάνθ' ὁ γηράσκων χρόνος. ÆSCH. PREFACE TO THE SECOND EDITION.