My answer to the objection, "I not only know, but know also that I know," would be, "Your knowing that you know only differs in words from your knowing. 'I know that I know' means nothing more than 'I know,' and this again, unless it is further determined, means nothing more than 'ego.' If your knowing and your knowing that you know are two different things, just try to separate them, and first to know without knowing that you know, then to know that you know without this knowledge being at the same time knowing." No doubt, by leaving all special knowing out of the question, we may at last arrive at the proposition "I know"—the last abstraction we are able to make; but this proposition is identical with "Objects exist for me," and this again is identical with "I am Subject," in which nothing more is contained than in the bare word "I."
Now, it may still be asked how the various cognitive faculties belonging to the Subject, such as Sensibility, Understanding, Reason, are known to us, if we do not know the Subject. It is not through our knowing having become an Object for us that these faculties are known to us, for then there would not be so many conflicting judgments concerning them; they are inferred rather, or more correctly, they are general expressions for the established classes of representations which, at all times, have been more or less clearly distinguished in those cognitive faculties. But, with reference to the necessary correlate of these representations as their condition, i.e., the Subject, these faculties are abstracted from them (the representations), and stand consequently towards the classes of representations in precisely the same relation as the Subject in general towards the Object in general. Now, just as the Object is at once posited with the Subject (for the word itself would otherwise have no meaning), and conversely, as the Subject is at once posited with the Object—so that being the Subject means exactly as much as having an Object, and being an Object means the same thing as being known by the Subject—so likewise, when an Object is assumed as being determined in any particular way, do we also assume that the Subject knows precisely in that particular way. So far therefore it is immaterial whether we say that Objects have such and such peculiar inherent determinations, or that the Subject knows in such and such ways. It is indifferent whether we say that Objects are divided into such and such classes, or that such and such different cognitive faculties are peculiar to the Subject. In that singular compound of depth and superficiality, Aristotle, are to be found traces even of insight into this truth, and indeed the critical philosophy lies in embryo in his works. He says:[152] ἡ ψυχὴ τὰ ὄντα πώς ἐστι πάντα (anima quammodo est universa, quæ sunt). And again: ὁ νοῦς ἐστι εἶδος εἰδῶν, i.e., the understanding is the form of forms, καὶ ἡ αἴσθησις εἶδος αἰσθητῶν, and sensibility the form of sensuous objects. Accordingly, it is all one whether we say, "sensibility and understanding are no more;" or, "the world is at an end." It comes to the same thing whether we say, "There are no conceptions," or "Reason is gone and animals alone remain."
The dispute between Realism and Idealism, which appeared for the last time in the dispute between the Dogmatists and Kantians, or between Ontology and Metaphysics on the one hand and Transcendental Æsthetic and Transcendental Logic on the other, arose out of the misapprehension of this relation and was based upon its misapprehension with reference to the First and Third Classes of representations as established by me, just as the mediæval dispute between Realists and Nominalists rested upon the misapprehension of this relation with reference to the Second Class.
§ 42. The Subject of Volition.
According to what has preceded, the Subject of knowledge can never be known; it can never become Object or representation. Nevertheless, as we have not only an outer self-knowledge (in sensuous perception), but an inner one also; and as, on the other hand, every knowledge, by its very nature, presupposes a knower and a known, what is known within us as such, is not the knower, but the willer, the Subject of Volition: the Will. Starting from knowledge, we may assert that "I know" is an analytical, "I will," on the contrary, a synthetical, and moreover an à posteriori proposition, that is, it is given by experience—in this case by inner experience (i.e., in Time alone). In so far therefore the Subject of volition would be an Object for us. Introspection always shows us to ourselves as willing. In this willing, however, there are numerous degrees, from the faintest wish to passion, and I have often shown[153] that not only all our emotions, but even all those movements of our inner man, which are subsumed under the wide conception of feeling, are states of the will.
Now, the identity of the willing with the knowing Subject, in virtue of which the word "I" includes and designates both, is the nodus[154] of the Universe, and therefore inexplicable. For we can only comprehend relations between Objects; but two Objects never can be one, excepting as parts of a whole. Here, where the Subject is in question, the rules by which we know Objects are no longer applicable, and actual identity of the knower with what is known as willing—that is, of Subject and Object—is immediately given. Now, whoever has clearly realized the utter impossibility of explaining this identity, will surely concur with me in calling it the miracle κατ' ἐξοχήν.
Just as the Understanding is the subjective correlate to our First Class of representations, the Reason to the Second, and pure Sensibility to the Third, so do we find that the correlate to this Fourth Class is the inner sense, or Self-consciousness in general.
§ 43. Willing. The Law of Motives (Motivation).
It is just because the willing Subject is immediately given in self-consciousness, that we are unable further to define or to describe what willing is; properly speaking, it is the most direct knowledge we have, nay, one whose immediateness must finally throw light upon every other knowledge, as being very mediate.
At every resolution that we take ourselves, or that we see others take, we deem ourselves justified in asking, why? That is, we assume that something must have previously occurred, from which this resolution has resulted, and we call this something its reason, or, more correctly, the motive of the action which now follows. Without such a reason or motive, the action is just as inconceivable for us, as the movement of a lifeless body without being pushed or pulled. Motives therefore belong to causes, and have also been already numbered and characterized among them in § 20, as the third form of Causality. But all Causality is only the form of the Principle of Sufficient Reason in the First Class of Objects: that is, in the corporeal world given us in external perception. There it forms the link which connects changes one with another, the cause being that which, coming from outside, conditions each occurrence. The inner nature of such occurrences on the contrary continues to be a mystery for us: for we always remain on the outside. We certainly see this cause necessarily produce that effect; but we do not learn how it is actually enabled to do so, or what is going on inside. Thus we see mechanical, physical, chemical effects, as well as those brought about by stimuli, in each instance follow from their respective causes without on that account ever completely understanding the process, the essential part of which remains a mystery for us; so we attribute it to qualities of bodies, to forces of Nature, or to vital energy, which, however, are all qualitates occultæ. Nor should we be at all better off as to comprehension of the movements and actions of animals and of human beings, which would also appear to us as induced in some unaccountable way by their causes (motives), were it not that here we are granted an insight into the inward part of the process; we know, that is, by our own inward experience, that this is an act of the will called forth by the motive, which consists in a mere representation. Thus the effect produced by the motive, unlike that produced by all other causes, is not only known by us from outside, in a merely indirect way, but at the same time from inside, quite directly, and therefore according to its whole mode of action. Here we stand as it were behind the scenes, and learn the secret of the process by which cause produces effect in its most inward nature; for here our knowledge comes to us through a totally different channel and in a totally different way. From this results the important proposition: The action of motives (motivation) is causality seen from within. Here accordingly causality presents itself in quite a different way, in quite a different medium, and for quite another kind of knowledge; therefore it must now be exhibited as a special and peculiar form of our principle, which consequently here presents itself as the Principle of the Sufficient Reason of Acting, principium rationis sufficientis agendi, or, more briefly, as the Law of Motives (Law of Motivation).