First Book. The World As Idea.
First Aspect. The Idea Subordinated To The Principle Of Sufficient Reason: The Object Of Experience And Science

Sors de l'enfance, ami réveille toi!

– Jean Jacques Rousseau.

§ 1. “The world is my idea:” – this is a truth which holds good for everything that lives and knows, though man alone can bring it into reflective and abstract consciousness. If he really does this, he has attained to philosophical wisdom. It then becomes clear and certain to him that what he knows is not a sun and an earth, but only an eye that sees a sun, a hand that feels an earth; that the world which surrounds him is there only as idea, i. e., only in relation to something else, the consciousness, which is himself. If any truth can be asserted a priori, it is this: for it is the expression of the most general form of all possible and thinkable experience: a form which is more general than time, or space, or causality, for they all presuppose it; and each of these, which we have seen to be just so many modes of the principle of sufficient reason, is valid only for a particular class of ideas; whereas the antithesis of object and subject is the common form of all these classes, is that form under which alone any idea of whatever kind it may be, abstract or intuitive, pure or empirical, is possible and thinkable. No truth therefore is more certain, more independent of all others, and less in need of proof than this, that all that exists for knowledge, and therefore this whole world, is only object in relation to subject, perception of a perceiver, in a word, idea. This is obviously true of the past and the future, as well as of the present, of what is farthest off, as of what is near; for it is true of time and space themselves, in which alone these distinctions arise. All that in any way belongs or can belong to the world is inevitably thus conditioned through the subject, and exists only for the subject. The world is idea.

This truth is by no means new. It was implicitly involved in the sceptical reflections from which Descartes started. Berkeley, however, was the first who distinctly enunciated it, and by this he has rendered a permanent service to philosophy, even though the rest of his teaching should not endure. Kant's primary mistake was the neglect of this principle, as is shown in the appendix. How early again this truth was recognised by the wise men of India, appearing indeed as the fundamental tenet of the Vedânta philosophy ascribed to Vyasa, is pointed out by Sir William Jones in the last of his essays: “On the philosophy of the Asiatics” (Asiatic Researches, vol. iv. p. 164), where he says, “The fundamental tenet of the Vedanta school consisted not in denying the existence of matter, that is, of solidity, impenetrability, and extended figure (to deny which would be lunacy), but in correcting the popular notion of it, and in contending that it has no essence independent of mental perception; that existence and perceptibility are convertible terms.” These words adequately express the compatibility of empirical reality and transcendental ideality.

In this first book, then, we consider the world only from this side, only so far as it is idea. The inward reluctance with which any one accepts the world as merely his idea, warns him that this view of it, however true it may be, is nevertheless one-sided, adopted in consequence of some arbitrary abstraction. And yet it is a conception from which he can never free himself. The defectiveness of this view will be corrected in the next book by means of a truth which is not so immediately certain as that from which we start here; a truth at which we can arrive only by deeper research and more severe abstraction, by the separation of what is different and the union of what is identical. This truth, which must be very serious and impressive if not awful to every one, is that a man can also say and must say, “the world is my will.”

In this book, however, we must consider separately that aspect of the world from which we start, its aspect as knowable, and therefore, in the meantime, we must, without reserve, regard all presented objects, even our own bodies (as we shall presently show more fully), merely as ideas, and call them merely ideas. By so doing we always abstract from will (as we hope to make clear to every one further on), which by itself constitutes the other aspect of the world. For as the world is in one aspect entirely idea, so in another it is entirely will. A reality which is neither of these two, but an object in itself (into which the thing in itself has unfortunately dwindled in the hands of Kant), is the phantom of a dream, and its acceptance is an ignis fatuus in philosophy.

§ 2. That which knows all things and is known by none is the subject. Thus it is the supporter of the world, that condition of all phenomena, of all objects which is always pre-supposed throughout experience; for all that exists, exists only for the subject. Every one finds himself to be subject, yet only in so far as he knows, not in so far as he is an object of knowledge. But his body is object, and therefore from this point of view we call it idea. For the body is an object among objects, and is conditioned by the laws of objects, although it is an immediate object. Like all objects of perception, it lies within the universal forms of knowledge, time and space, which are the conditions of multiplicity. The subject, on the contrary, which is always the knower, never the known, does not come under these forms, but is presupposed by them; it has therefore neither multiplicity nor its opposite unity. We never know it, but it is always the knower wherever there is knowledge.

So then the world as idea, the only aspect in which we consider it at present, has two fundamental, necessary, and inseparable halves. The one half is the object, the forms of which are space and time, and through these multiplicity. The other half is the subject, which is not in space and time, for it is present, entire and undivided, in every percipient being. So that any one percipient being, with the object, constitutes the whole world as idea just as fully as the existing millions could do; but if this one were to disappear, then the whole world as idea would cease to be. These halves are therefore inseparable even for thought, for each of the two has meaning and existence only through and for the other, each appears with the other and vanishes with it. They limit each other immediately; where the object begins the subject ends. The universality of this limitation is shown by the fact that the essential and hence universal forms of all objects, space, time, and causality, may, without knowledge of the object, be discovered and fully known from a consideration of the subject, i. e., in Kantian language, they lie a priori in our consciousness. That he discovered this is one of Kant's principal merits, and it is a great one. I however go beyond this, and maintain that the principle of sufficient reason is the general expression for all these forms of the object of which we are a priori conscious; and that therefore all that we know purely a priori, is merely the content of that principle and what follows from it; in it all our certain a priori knowledge is expressed. In my essay on the principle of sufficient reason I have shown in detail how every possible object comes under it; that is, stands in a necessary relation to other objects, on the one side as determined, on the other side as determining: this is of such wide application, that the whole existence of all objects, so far as they are objects, ideas and nothing more, may be entirely traced to this their necessary relation to each other, rests only in it, is in fact merely relative; but of this more presently. I have further shown, that the necessary relation which the principle of sufficient reason expresses generally, appears in other forms corresponding to the classes into which objects are divided, according to their possibility; and again that by these forms the proper division of the classes is tested. I take it for granted that what I said in this earlier essay is known and present to the reader, for if it had not been already said it would necessarily find its place here.

§ 3. The chief distinction among our ideas is that between ideas of perception and abstract ideas. The latter form just one class of ideas, namely concepts, and these are the possession of man alone of all creatures upon earth. The capacity for these, which distinguishes him from all the lower animals, has always been called reason.⁵ We shall consider these abstract ideas by themselves later, but, in the first place, we shall speak exclusively of the ideas of perception. These comprehend the whole visible world, or the sum total of experience, with the conditions of its possibility. We have already observed that it is a highly important discovery of Kant's, that these very conditions, these forms of the visible world, i. e., the absolutely universal element in its perception, the common property of all its phenomena, space and time, even when taken by themselves and apart from their content, can, not only be thought in the abstract, but also be directly perceived; and that this perception or intuition is not some kind of phantasm arising from constant recurrence in experience, but is so entirely independent of experience that we must rather regard the latter as dependent on it, inasmuch as the qualities of space and time, as they are known in a priori perception or intuition, are valid for all possible experience, as rules to which it must invariably conform. Accordingly, in my essay on the principle of sufficient reason, I have treated space and time, because they are perceived as pure and empty of content, as a special and independent class of ideas. This quality of the universal forms of intuition, which was discovered by Kant, that they may be perceived in themselves and apart from experience, and that they may be known as exhibiting those laws on which is founded the infallible science of mathematics, is certainly very important. Not less worthy of remark, however, is this other quality of time and space, that the principle of sufficient reason, which conditions experience as the law of causation and of motive, and thought as the law of the basis of judgment, appears here in quite a special form, to which I have given the name of the ground of being. In time, this is the succession of its moments, and in space the position of its parts, which reciprocally determine each other ad infinitum.

Any one who has fully understood from the introductory essay the complete identity of the content of the principle of sufficient reason in all its different forms, must also be convinced of the importance of the knowledge of the simplest of these forms, as affording him insight into his own inmost nature. This simplest form of the principle we have found to be time. In it each instant is, only in so far as it has effaced the preceding one, its generator, to be itself in turn as quickly effaced. The past and the future (considered apart from the consequences of their content) are empty as a dream, and the present is only the indivisible and unenduring boundary between them. And in all the other forms of the principle of sufficient reason, we shall find the same emptiness, and shall see that not time only but also space, and the whole content of both of them, i. e., all that proceeds from causes and motives, has a merely relative existence, is only through and for another like to itself, i. e., not more enduring. The substance of this doctrine is old: it appears in Heraclitus when he laments the eternal flux of things; in Plato when he degrades the object to that which is ever becoming, but never being; in Spinoza as the doctrine of the mere accidents of the one substance which is and endures. Kant opposes what is thus known as the mere phenomenon to the thing in itself. Lastly, the ancient wisdom of the Indian philosophers declares, “It is Mâyâ, the veil of deception, which blinds the eyes of mortals, and makes them behold a world of which they cannot say either that it is or that it is not: for it is like a dream; it is like the sunshine on the sand which the traveller takes from afar for water, or the stray piece of rope he mistakes for a snake.” (These similes are repeated in innumerable passages of the Vedas and the Puranas.) But what all these mean, and that of which they all speak, is nothing more than what we have just considered – the world as idea subject to the principle of sufficient reason.

§ 4. Whoever has recognised the form of the principle of sufficient reason, which appears in pure time as such, and on which all counting and arithmetical calculation rests, has completely mastered the nature of time. Time is nothing more than that form of the principle of sufficient reason, and has no further significance. Succession is the form of the principle of sufficient reason in time, and succession is the whole nature of time. Further, whoever has recognised the principle of sufficient reason as it appears in the presentation of pure space, has exhausted the whole nature of space, which is absolutely nothing more than that possibility of the reciprocal determination of its parts by each other, which is called position. The detailed treatment of this, and the formulation in abstract conceptions of the results which flow from it, so that they may be more conveniently used, is the subject of the science of geometry. Thus also, whoever has recognised the law of causation, the aspect of the principle of sufficient reason which appears in what fills these forms (space and time) as objects of perception, that is to say matter, has completely mastered the nature of matter as such, for matter is nothing more than causation, as any one will see at once if he reflects. Its true being is its action, nor can we possibly conceive it as having any other meaning. Only as active does it fill space and time; its action upon the immediate object (which is itself matter) determines that perception in which alone it exists. The consequence of the action of any material object upon any other, is known only in so far as the latter acts upon the immediate object in a different way from that in which it acted before; it consists only of this. Cause and effect thus constitute the whole nature of matter; its true being is its action. (A fuller treatment of this will be found in the essay on the Principle of Sufficient Reason, § 21, p. 77.) The nature of all material things is therefore very appropriately called in German Wirklichkeit,⁶ a word which is far more expressive than Realität. Again, that which is acted upon is always matter, and thus the whole being and essence of matter consists in the orderly change, which one part of it brings about in another part. The existence of matter is therefore entirely relative, according to a relation which is valid only within its limits, as in the case of time and space.

But time and space, each for itself, can be mentally presented apart from matter, whereas matter cannot be so presented apart from time and space. The form which is inseparable from it presupposes space, and the action in which its very existence consists, always imports some change, in other words a determination in time. But space and time are not only, each for itself, presupposed by matter, but a union of the two constitutes its essence, for this, as we have seen, consists in action, i. e., in causation. All the innumerable conceivable phenomena and conditions of things, might be coexistent in boundless space, without limiting each other, or might be successive in endless time without interfering with each other: thus a necessary relation of these phenomena to each other, and a law which should regulate them according to such a relation, is by no means needful, would not, indeed, be applicable: it therefore follows that in the case of all co-existence in space and change in time, so long as each of these forms preserves for itself its condition and its course without any connection with the other, there can be no causation, and since causation constitutes the essential nature of matter, there can be no matter. But the law of causation receives its meaning and necessity only from this, that the essence of change does not consist simply in the mere variation of things, but rather in the fact that at the same part of space there is now one thing and then another, and at one and the same point of time there is here one thing and there another: only this reciprocal limitation of space and time by each other gives meaning, and at the same time necessity, to a law, according to which change must take place. What is determined by the law of causality is therefore not merely a succession of things in time, but this succession with reference to a definite space, and not merely existence of things in a particular place, but in this place at a different point of time. Change, i. e., variation which takes place according to the law of causality, implies always a determined part of space and a determined part of time together and in union. Thus causality unites space with time. But we found that the whole essence of matter consisted in action, i. e., in causation, consequently space and time must also be united in matter, that is to say, matter must take to itself at once the distinguishing qualities both of space and time, however much these may be opposed to each other, and must unite in itself what is impossible for each of these independently, that is, the fleeting course of time, with the rigid unchangeable perduration of space: infinite divisibility it receives from both. It is for this reason that we find that co-existence, which could neither be in time alone, for time has no contiguity, nor in space alone, for space has no before, after, or now, is first established through matter. But the co-existence of many things constitutes, in fact, the essence of reality, for through it permanence first becomes possible; for permanence is only knowable in the change of something which is present along with what is permanent, while on the other hand it is only because something permanent is present along with what changes, that the latter gains the special character of change, i. e., the mutation of quality and form in the permanence of substance, that is to say, in matter.⁷