is, as Plato so often remarks, a sine qua non of philosophy. But hitherto it was not recognised that every kind of active and operating force in nature is essentially identical with will, and therefore the multifarious kinds of phenomena were not seen to be merely different species of the same genus, but were treated as heterogeneous. Consequently there could be no word to denote the concept of this genus. I therefore name the genus after its most important species, the direct knowledge of which lies nearer to us and guides us to the indirect knowledge of all other species. But whoever is incapable of carrying out the required extension of the concept will remain involved in a permanent misunderstanding. For by the word will he understands only that species of it which has hitherto been exclusively denoted by it, the will which is guided by knowledge, and whose manifestation follows only upon motives, and indeed merely abstract motives, and thus takes place under the guidance of the reason. This, we have said, is only the most prominent example of the manifestation of will. We must now distinctly separate in thought the inmost essence of this manifestation which is known to us directly, and then transfer it to all the weaker, less distinct manifestations of the same nature, and thus we shall accomplish the desired extension of the concept of will. From another point of view I should be equally misunderstood by any one who should think that it is all the same in the end whether we denote this inner nature of all phenomena by the word will or by any other. This would be the case if the thing-in-itself were something whose existence we merely inferred, and thus knew indirectly and only in the abstract. Then, indeed, we might call it what we pleased; the name would stand merely as the symbol of an unknown quantity. But the word will, which, like a magic spell, discloses to us the inmost being of everything in nature, is by no means an unknown quantity, something arrived at only by inference, but is fully and immediately comprehended, and is so familiar to us that we know and understand what will is far better than anything else whatever. The concept of will has hitherto commonly been subordinated to that of force, but I reverse the matter entirely, and desire that every force in nature should be thought as will. It must not be supposed that this is mere verbal quibbling or of no consequence; rather, it is of the greatest significance and importance. For at the foundation of the concept of force, as of all other concepts, there ultimately lies the knowledge in sense-perception of the objective world, that is to say, the phenomenon, the idea; and the concept is constructed out of this. It is an abstraction from the province in which cause and effect reign, i.e., from ideas of perception, and means just the causal nature of causes at the point at which this causal nature is no further etiologically explicable, but is the necessary presupposition of all etiological explanation. The concept will, on the other hand, is of all possible concepts the only one which has its source not in the phenomenal, not in the mere idea of perception, but comes from within, and proceeds from the most immediate consciousness of each of us, in which each of us knows his own individuality, according to its nature, immediately, apart from all form, even that of subject and object, and which at the same time is this individuality, for here the subject and the object of knowledge are one. If, therefore, we refer the concept of force to that of will, we have in fact referred the less known to what is infinitely better known; indeed, to the one thing that is really immediately and fully known to us, and have very greatly extended our knowledge. If, on the contrary, we subsume the concept of will under that of force, as has hitherto always been done, we renounce the only immediate knowledge which we have of the inner nature of the world, for we allow it to disappear in a concept which is abstracted from the phenomenal, and with which we can therefore never go beyond the phenomenal.
§ 23. The will as a thing in itself is quite different from its phenomenal appearance, and entirely free from all the forms of the phenomenal, into which it first passes when it manifests itself, and which therefore only concern its objectivity, and are foreign to the will itself. Even the most universal form of all idea, that of being object for a subject, does not concern it; still less the forms which are subordinate to this and which collectively have their common expression in the principle of sufficient reason, to which we know that time and space belong, and consequently multiplicity also, which exists and is possible only through these. In this last regard I shall call time and space the principium individuationis, borrowing an expression from the old schoolmen, and I beg to draw attention to this, once for all. For it is only through the medium of time and space that what is one and the same, both according to its nature and to its concept, yet appears as different, as a multiplicity of co-existent and successive phenomena. Thus time and space are the principium individuationis, the subject of so many subtleties and disputes among the schoolmen, which may be found collected in Suarez (Disp. 5, Sect. 3). According to what has been said, the will as a thing-in-itself lies outside the province of the principle of sufficient reason in all its forms, and is consequently completely groundless, although all its manifestations are entirely subordinated to the principle of sufficient reason. Further, it is free from all multiplicity, although its manifestations in time and space are innumerable. It is itself one, though not in the sense in which an object is one, for the unity of an object can only be known in opposition to a possible multiplicity; nor yet in the sense in which a concept is one, for the unity of a concept originates only in abstraction from a multiplicity; but it is one as that which lies outside time and space, the principium individuationis, i.e., the possibility of multiplicity. Only when all this has become quite clear to us through the subsequent examination of the phenomena and different manifestations of the will, shall we fully understand the meaning of the Kantian doctrine that time, space and causality do not belong to the thing-in-itself, but are only forms of knowing.
The uncaused nature of will has been actually recognised, where it manifests itself most distinctly, as the will of man, and this has been called free, independent. But on account of the uncaused nature of the will itself, the necessity to which its manifestation is everywhere subjected has been overlooked, and actions are treated as free, which they are not. For every individual action follows with strict necessity from the effect of the motive upon the character. All necessity is, as we have already said, the relation of the consequent to the reason, and nothing more. The principle of sufficient reason is the universal form of all phenomena, and man in his action must be subordinated to it like every other phenomenon. But because in self-consciousness the will is known directly and in itself, in this consciousness lies also the consciousness of freedom. The fact is, however, overlooked that the individual, the person, is not will as a thing-in-itself, but is a phenomenon of will, is already determined as such, and has come under the form of the phenomenal, the principle of sufficient reason. Hence arises the strange fact that every one believes himself a priori to be perfectly free, even in his individual actions, and thinks that at every moment he can commence another manner of life, which just means that he can become another person. But a posteriori, through experience, he finds to his astonishment that he is not free, but subjected to necessity; that in spite of all his resolutions and reflections he does not change his conduct, and that from the beginning of his life to the end of it, he must carry out the very character which he himself condemns, and as it were play the part he has undertaken to the end. I cannot pursue this subject further at present, for it belongs, as ethical, to another part of this work. In the meantime, I only wish to point out here that the phenomenon of the will which in itself is uncaused, is yet as such subordinated to the law of necessity, that is, the principle of sufficient reason, so that in the necessity with which the phenomena of nature follow each other, we may find nothing to hinder us from recognising in them the manifestations of will.
Only those changes which have no other ground than a motive, i.e., an idea, have hitherto been regarded as manifestations of will. Therefore in nature a will has only been attributed to man, or at the most to animals; for knowledge, the idea, is of course, as I have said elsewhere, the true and exclusive characteristic of animal life. But that the will is also active where no knowledge guides it, we see at once in the instinct and the mechanical skill of animals.31 That they have ideas and knowledge is here not to the point, for the end towards which they strive as definitely as if it were a known motive, is yet entirely unknown to them. Therefore in such cases their action takes place without motive, is not guided by the idea, and shows us first and most distinctly how the will may be active entirely without knowledge. The bird of a year old has no idea of the eggs for which it builds a nest; the young spider has no idea of the prey for which it spins a web; nor has the ant-lion any idea of the
