On the Fourfold Root of the Principle of Sufficient...

I have endeavoured in this treatise to show that the Principle of Sufficient Reason is a common expression for four completely different relations, each of which is founded upon a particular law given à priori (the principle of sufficient reason being a synthetical à priori principle). Now, according to the principle of homogeneity, we are compelled to assume that these four laws, discovered according to the principle of specification, as they agree in being expressed by one and the same term, must necessarily spring from one and the same original quality of our whole cognitive faculty as their common root, which we should accordingly have to look upon as the innermost germ of all dependence, relativeness, instability and limitation of the objects of our consciousness—itself limited to Sensibility, Understanding, Reason, Subject and Object—or of that world, which the divine Plato repeatedly degrades to the ἀεὶ γιγνόμενον μὲν καὶ ἀπολλύμενον, ὄντως δὲ οὐδέποτε ὄν (ever arising and perishing, but in fact never existing), the knowledge of which is merely a δόξα μετ' αἰσθήσεως ἀλόγου, and which Christendom, with a correct instinct, calls temporal, after that form of our principle (Time) which I have defined as its simplest schema and the prototype of all limitation. The general meaning of the Principle of Sufficient Reason may, in the main, be brought back to this: that every thing existing no matter when or where, exists by reason of something else.

Now, the Principle of Sufficient Reason is nevertheless à priori in all its forms: that is, it has its root in our intellect, therefore it must not be applied to the totality of existent things, the Universe, including that intellect in which it presents itself. For a world like this, which presents itself in virtue of à priori forms, is just on that account mere phenomenon; consequently that which holds good with reference to it as the result of these forms, cannot be applied to the world itself, i.e. to the thing in itself, representing itself in that world. Therefore we cannot say, "the world and all things in it exist by reason of something else;" and this proposition is precisely the Cosmological Proof.

If, by the present treatise, I have succeeded in deducing the result just expressed, it seems to me that every speculative philosopher who founds a conclusion upon the Principle of Sufficient Reason or indeed talks of a reason at all, is bound to specify which kind of reason he means. One might suppose that wherever there was any question of a reason, this would be done as a matter of course, and that all confusion would thus be impossible. Only too often, however, do we still find either the terms reason and cause confounded in indiscriminate use; or do we hear basis and what is based, condition and what is conditioned, principia and principiata talked about in quite a general way without any nearer determination, perhaps because there is a secret consciousness that these conceptions are being used in an unauthorized way. Thus even Kant speaks of the thing in itself as the reason[161] of the phenomenon, and also of a ground of the possibility of all phenomena,[162] of an intelligible cause of phenomena, of an unknown ground of the possibility of the sensuous series in general, of a transcendental object[163] as the ground of all phenomena and of the reason why our sensibility should have this rather than all other supreme conditions, and so on in several places. Now all this does not seem to me to tally with those weighty, profound, nay immortal words of his,[164] "the contingency[165] of things is itself mere phenomenon, and can lead to no other than the empirical regressus which determines phenomena."

That since Kant the conceptions reason and consequence, principium and principiatum, &c. &c., have been and still are used in a yet more indefinite and even quite transcendent sense, everyone must know who is acquainted with the more recent works on philosophy.

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.