Chapter VI: Part 6

As regards the _content_ of the sciences generally, it is, in fact, always the relation of the phenomena of the world to each other, according to the principle of sufficient reason, under the guidance of the _why_, which has validity and meaning only through this principle. _Explanation_ is the establishment of this relation. Therefore explanation can never go further than to show two ideas standing to each other in the relation peculiar to that form of the principle of sufficient reason which reigns in the class to which they belong. If this is done we cannot further be asked the question, _why_: for the relation proved is that one which absolutely cannot be imagined as other than it is, _i.e._, it is the form of all knowledge. Therefore we do not ask why 2 + 2 = 4; or why the equality of the angles of a triangle determines the equality of the sides; or why its effect follows any given cause; or why the truth of the conclusion is evident from the truth of the premises. Every explanation which does not ultimately lead to a relation of which no “why” can further be demanded, stops at an accepted _qualitas occulta_; but this is the character of every original force of nature. Every explanation in natural science must ultimately end with such a _qualitas occulta_, and thus with complete obscurity. It must leave the inner nature of a stone just as much unexplained as that of a human being; it can give as little account of the weight, the cohesion, the chemical qualities, &c., of the former, as of the knowing and acting of the latter. Thus, for example, weight is a _qualitas occulta_, for it can be thought away, and does not proceed as a necessity from the form of knowledge; which, on the contrary, is not the case with the law of inertia, for it follows from the law of causality, and is therefore sufficiently explained if it is referred to that law. There are two things which are altogether inexplicable,—that is to say, do not ultimately lead to the relation which the principle of sufficient reason expresses. These are, first, the principle of sufficient reason itself in all its four forms, because it is the principle of all explanation, which has meaning only in relation to it; secondly, that to which this principle does not extend, but which is the original source of all phenomena; the thing-in-itself, the knowledge of which is not subject to the principle of sufficient reason. We must be content for the present not to understand this thing-in-itself, for it can only be made intelligible by means of the following book, in which we shall resume this consideration of the possible achievements of the sciences. But at the point at which natural science, and indeed every science, leaves things, because not only its explanation of them, but even the principle of this explanation, the principle of sufficient reason, does not extend beyond this point; there philosophy takes them up and treats them after its own method, which is quite distinct from the method of science. In my essay on the principle of sufficient reason, § 51, I have shown how in the different sciences the chief guiding clue is one or other form of that principle; and, in fact, perhaps the most appropriate classification of the sciences might be based upon this circumstance. Every explanation arrived at by the help of this clue is, as we have said, merely relative; it explains things in relation to each other, but something which indeed is presupposed is always left unexplained. In mathematics, for example, this is space and time; in mechanics, physics, and chemistry it is matter, qualities, original forces and laws of nature; in botany and zoology it is the difference of species, and life itself; in history it is the human race with all its properties of thought and will: in all it is that form of the principle of sufficient reason which is respectively applicable. It is peculiar to _philosophy_ that it presupposes nothing as known, but treats everything as equally external and a problem; not merely the relations of phenomena, but also the phenomena themselves, and even the principle of sufficient reason to which the other sciences are content to refer everything. In philosophy nothing would be gained by such a reference, as one member of the series is just as external to it as another; and, moreover, that kind of connection is just as much a problem for philosophy as what is joined together by it, and the latter again is just as much a problem after its combination has been explained as before it. For, as we have said, just what the sciences presuppose and lay down as the basis and the limits of their explanation, is precisely and peculiarly the problem of philosophy, which may therefore be said to begin where science ends. It cannot be founded upon demonstrations, for they lead from known principles to unknown, but everything is equally unknown and external to philosophy. There can be no principle in consequence of which the world with all its phenomena first came into existence, and therefore it is not possible to construct, as Spinoza wished, a philosophy which demonstrates _ex firmis principiis_. Philosophy is the most general rational knowledge, the first principles of which cannot therefore be derived from another principle still more general. The principle of contradiction establishes merely the agreement of concepts, but does not itself produce concepts. The principle of sufficient reason explains the connections of phenomena, but not the phenomena themselves; therefore philosophy cannot proceed upon these principles to seek a _causa efficiens_ or a _causa finalis_ of the whole world. My philosophy, at least, does not by any means seek to know _whence_ or _wherefore_ the world exists, but merely _what_ the world is. But the _why_ is here subordinated to the _what_, for it already belongs to the world, as it arises and has meaning and validity only through the form of its phenomena, the principle of sufficient reason. We might indeed say that every one knows what the world is without help, for he is himself that subject of knowledge of which the world is the idea; and so far this would be true. But that knowledge is empirical, is in the concrete; the task of philosophy is to reproduce this in the abstract to raise to permanent rational knowledge the successive changing perceptions, and in general, all that is contained under the wide concept of feeling and merely negatively defined as not abstract, distinct, rational knowledge. It must therefore consist of a statement in the abstract, of the nature of the whole world, of the whole, and of all the parts. In order then that it may not lose itself in the endless multitude of particular judgments, it must make use of abstraction and think everything individual in the universal, and its differences also in the universal. It must therefore partly separate and partly unite, in order to present to rational knowledge the whole manifold of the world generally, according to its nature, comprehended in a few abstract concepts. Through these concepts, in which it fixes the nature of the world, the whole individual must be known as well as the universal, the knowledge of both therefore must be bound together to the minutest point. Therefore the capacity for philosophy consists just in that in which Plato placed it, the knowledge of the one in the many, and the many in the one. Philosophy will therefore be a sum-total of general judgments, whose ground of knowledge is immediately the world itself in its entirety, without excepting anything; thus all that is to be found in human consciousness; it will be _a complete recapitulation, as it were, a reflection, of the world in abstract concepts_, which is only possible by the union of the essentially identical in _one_ concept and the relegation of the different to another. This task was already prescribed to philosophy by Bacon of Verulam when he said: _ea demum vera est philosophia, quae mundi ipsius voces fidelissime reddit, et veluti dictante mundo conscripta est, et nihil aliud est, quam ejusdem_ SIMULACRUM ET REFLECTIO, _neque addit quidquam de proprio, sed tantum iterat et resonat_ (De Augm. Scient., L. 2, c. 13). But we take this in a wider sense than Bacon could then conceive.

The agreement which all the sides and parts of the world have with each other, just because they belong to a whole, must also be found in this abstract copy of it. Therefore the judgments in this sum-total could to a certain extent be deduced from each other, and indeed always reciprocally so deduced. Yet to make the first judgment possible, they must all be present, and thus implied as prior to it in the knowledge of the world in the concrete, especially as all direct proof is more certain than indirect proof; their harmony with each other by virtue of which they come together into the unity of _one_ thought, and which arises from the harmony and unity of the world of perception itself, which is their common ground of knowledge, is not therefore to be made use of to establish them, as that which is prior to them, but is only added as a confirmation of their truth. This problem itself can only become quite clear in being solved.(23)

§ 16. After this full consideration of reason as a special faculty of knowledge belonging to man alone, and the results and phenomena peculiar to human nature brought about by it, it still remains for me to speak of reason, so far as it is the guide of human action, and in this respect may be called _practical_. But what there is to say upon this point has found its place elsewhere in the appendix to this work, where I controvert the existence of the so-called practical reason of Kant, which he (certainly very conveniently) explained as the immediate source of virtue, and as the seat of an absolute (_i.e._, fallen from heaven) imperative. The detailed and thorough refutation of this Kantian principle of morality I have given later in the “Fundamental Problems of Ethics.” There remains, therefore, but little for me to say here about the actual influence of reason, in the true sense of the word, upon action. At the commencement of our treatment of reason we remarked, in general terms, how much the action and behaviour of men differs from that of brutes, and that this difference is to be regarded as entirely due to the presence of abstract concepts in consciousness. The influence of these upon our whole existence is so penetrating and significant that, on account of them, we are related to the lower animals very much as those animals that see are related to those that have no eyes (certain larvae, worms, and zoophytes). Animals without eyes know only by touch what is immediately present to them in space, what comes into contact with them; those which see, on the contrary, know a wide circle of near and distant objects. In the same way the absence of reason confines the lower animals to the ideas of perception, _i.e._, the real objects which are immediately present to them in time; we, on the contrary, on account of knowledge in the abstract, comprehend not only the narrow actual present, but also the whole past and future, and the wide sphere of the possible; we view life freely on all its sides, and go far beyond the present and the actual. Thus what the eye is in space and for sensuous knowledge, reason is, to a certain extent, in time and for inner knowledge. But as the visibility of objects has its worth and meaning only in the fact that it informs us of their tangibility, so the whole worth of abstract knowledge always consists in its relation to what is perceived. Therefore men naturally attach far more worth to immediate and perceived knowledge than to abstract concepts, to that which is merely thought; they place empirical knowledge before logical. But this is not the opinion of men who live more in words than in deeds, who have seen more on paper and in books than in actual life, and who in their greatest degeneracy become pedants and lovers of the mere letter. Thus only is it conceivable that Leibnitz and Wolf and all their successors could go so far astray as to explain knowledge of perception, after the example of Duns Scotus, as merely confused abstract knowledge! To the honour of Spinoza, I must mention that his truer sense led him, on the contrary, to explain all general concepts as having arisen from the confusion of that which was known in perception (Eth. II., prop. 40, Schol. 1). It is also a result of perverted opinion that in mathematics the evidence proper to it was rejected, and logical evidence alone accepted; that everything in general which was not abstract knowledge was comprehended under the wide name of feeling, and consequently was little valued; and lastly that the Kantian ethics regarded the good will which immediately asserts itself upon knowledge of the circumstances, and guides to right and good action as mere feeling and emotion, and consequently as worthless and without merit, and would only recognise actions which proceed from abstract maxims as having moral worth.

The many-sided view of life as a whole which man, as distinguished from the lower animals, possesses through reason, may be compared to a geometrical, colourless, abstract, reduced plan of his actual life. He, therefore, stands to the lower animals as the navigator who, by means of chart, compass, and quadrant, knows accurately his course and his position at any time upon the sea, stands to the uneducated sailors who see only the waves and the heavens. Thus it is worth noticing, and indeed wonderful, how, besides his life in the concrete, man always lives another life in the abstract. In the former he is given as a prey to all the storms of actual life, and to the influence of the present; he must struggle, suffer, and die like the brute. But his life in the abstract, as it lies before his rational consciousness, is the still reflection of the former, and of the world in which he lives; it is just that reduced chart or plan to which we have referred. Here in the sphere of quiet deliberation, what completely possessed him and moved him intensely before, appears to him cold, colourless, and for the moment external to him; he is merely the spectator, the observer. In respect of this withdrawal into reflection he may be compared to an actor who has played his part in one scene, and who takes his place among the audience till it is time for him to go upon the stage again, and quietly looks on at whatever may happen, even though it be the preparation for his own death (in the piece), but afterwards he again goes on the stage and acts and suffers as he must. From this double life proceeds that quietness peculiar to human beings, so very different from the thoughtlessness of the brutes, and with which, in accordance with previous reflection, or a formed determination, or a recognised necessity, a man suffers or accomplishes in cold blood, what is of the utmost and often terrible importance to him; suicide, execution, the duel, enterprises of every kind fraught with danger to life, and, in general, things against which his whole animal nature rebels. Under such circumstances we see to what an extent reason has mastered the animal nature, and we say to the strong: σιδηρειον νυ τοι ἡτορ! (_ferreum certe tibi cor_), Il. 24, 521. Here we can say truly that reason manifests itself practically, and thus wherever action is guided by reason, where the motives are abstract concepts, wherever we are not determined by particular ideas of perception, nor by the impression of the moment which guides the brutes, there _practical reason_ shows itself. But I have fully explained in the Appendix, and illustrated by examples, that this is entirely different from and unrelated to the ethical worth of actions; that rational action and virtuous action are two entirely different things; that reason may just as well find itself in connection with great evil as with great good, and by its assistance may give great power to the one as well as to the other; that it is equally ready and valuable for the methodical and consistent carrying out of the noble and of the bad intention, of the wise as of the foolish maxim; which all results from the constitution of its nature, which is feminine, receptive, retentive, and not spontaneous; all this I have shown in detail in the Appendix, and illustrated by examples. What is said there would have been placed here, but on account of my polemic against Kant’s pretended practical reason I have been obliged to relegate it to the Appendix, to which I therefore refer.

The ideal explained in the _Stoical philosophy_ is the most complete development of _practical reason_ in the true and genuine sense of the word; it is the highest summit to which man can attain by the mere use of his reason, and in it his difference from the brutes shows itself most distinctly. For the ethics of Stoicism are originally and essentially, not a doctrine of virtue, but merely a guide to a rational life, the end and aim of which is happiness through peace of mind. Virtuous conduct appears in it as it were merely by accident, as the means, not as the end. Therefore the ethical theory of Stoicism is in its whole nature and point of view fundamentally different from the ethical systems which lay stress directly upon virtue, such as the doctrines of the Vedas, of Plato, of Christianity, and of Kant. The aim of Stoical ethics is happiness: τελος το ευδαι μονειν (_virtutes omnes finem habere beatitudinem_) it is called in the account of the Stoa by Stobæus (Ecl., L. ii. c. 7, p. 114, and also p. 138). Yet the ethics of Stoicism teach that happiness can only be attained with certainty through inward peace and quietness of spirit (αταραξια), and that this again can only be reached through virtue; this is the whole meaning of the saying that virtue is the highest good. But if indeed by degrees the end is lost sight of in the means, and virtue is inculcated in a way which discloses an interest entirely different from that of one’s own happiness, for it contradicts this too distinctly; this is just one of those inconsistencies by means of which, in every system, the immediately known, or, as it is called, felt truth leads us back to the right way in defiance of syllogistic reasoning; as, for example, we see clearly in the ethical teaching of Spinoza, which deduces a pure doctrine of virtue from the egoistical _suum utile quærere_ by means of palpable sophisms. According to this, as I conceive the spirit of the Stoical ethics, their source lies in the question whether the great prerogative of man, reason, which, by means of planned action and its results, relieves life and its burdens so much, might not also be capable of freeing him at once, directly, _i.e._, through mere knowledge, completely, or nearly so, of the sorrows and miseries of every kind of which his life is full. They held that it was not in keeping with the prerogative of reason that the nature given with it, which by means of it comprehends and contemplates an infinity of things and circumstances, should yet, through the present, and the accidents that can be contained in the few years of a life that is short, fleeting, and uncertain, be exposed to such intense pain, to such great anxiety and suffering, as arise from the tempestuous strain of the desires and the antipathies; and they believed that the due application of reason must raise men above them, and can make them invulnerable. Therefore Antisthenes says: Δει κτασθαι νουν, η βροχον (_aut mentem parandam, aut laqueum._ Plut. de stoic. repugn., c. 14), _i.e._, life is so full of troubles and vexations, that one must either rise above it by means of corrected thoughts, or leave it. It was seen that want and suffering did not directly and of necessity spring from not having, but from desiring to have and not having; that therefore this desire to have is the necessary condition under which alone it becomes a privation not to have and begets pain. Ου πενια λυπην εργαζεται, αλλα επιθυμια (_non paupertas dolorem efficit, sed cupiditas_), Epict., fragm. 25. Men learned also from experience that it is only the hope of what is claimed that begets and nourishes the wish; therefore neither the many unavoidable evils which are common to all, nor unattainable blessings, disquiet or trouble us, but only the trifling more or less of those things which we can avoid or attain; indeed, not only what is absolutely unavoidable or unattainable, but also what is merely relatively so, leaves us quite undisturbed; therefore the ills that have once become joined to our individuality, or the good things that must of necessity always be denied us, are treated with indifference, in accordance with the peculiarity of human nature that every wish soon dies and can no more beget pain if it is not nourished by hope. It followed from all this that happiness always depends upon the proportion between our claims and what we receive. It is all one whether the quantities thus related be great or small, and the proportion can be established just as well by diminishing the amount of the first as by increasing the amount of the second; and in the same way it also follows that all suffering proceeds from the want of proportion between what we demand and expect and what we get. Now this want of proportion obviously lies only in knowledge, and it could be entirely abolished through fuller insight.(24) Therefore Chrysippus says: δει ζῃν κατ᾽ εμπειριαν των φυσει συμβαινοντων (Stob. Ecl., L. ii. c. 7, p. 134), that is, one ought to live with a due knowledge of the transitory nature of the things of the world. For as often as a man loses self-command, or is struck down by a misfortune, or grows angry, or becomes faint-hearted, he shows that he finds things different from what he expected, consequently that he was caught in error, and did not know the world and life, did not know that the will of the individual is crossed at every step by the chance of inanimate nature and the antagonism of aims and the wickedness of other individuals: he has therefore either not made use of his reason in order to arrive at a general knowledge of this characteristic of life, or he lacks judgment, in that he does not recognise in the particular what he knows in general, and is therefore surprised by it and loses his self-command.(25) Thus also every keen pleasure is an error and an illusion, for no attained wish can give lasting satisfaction; and, moreover, every possession and every happiness is but lent by chance for an uncertain time, and may therefore be demanded back the next hour. All pain rests on the passing away of such an illusion; thus both arise from defective knowledge; the wise man therefore holds himself equally aloof from joy and sorrow, and no event disturbs his αταραξια.

In accordance with this spirit and aim of the Stoa, Epictetus began and ended with the doctrine as the kernel of his philosophy, that we should consider well and distinguish what depends upon us and what does not, and therefore entirely avoid counting upon the latter, whereby we shall certainly remain free from all pain, sorrow, and anxiety. But that which alone is dependent upon us is the will; and here a transition gradually takes place to a doctrine of virtue, for it is observed that as the outer world, which is independent of us, determines good and bad fortune, so inner contentment with ourselves, or the absence of it, proceeds from the will. But it was then asked whether we ought to apply the words _bonum_ and _malum_ to the two former or to the two latter? This was indeed arbitrary and a matter of choice, and did not make any real difference, but yet the Stoics disputed everlastingly with the Peripatetics and Epicureans about it, and amused themselves with the inadmissible comparison of two entirely incommensurable quantities, and the antithetical, paradoxical judgments which proceeded from them, and which they flung at each other. The _Paradoxa_ of Cicero afford us an interesting collection of these from the Stoical side.

Zeno, the founder, seems originally to have followed a somewhat different path. The starting-point with him was that for the attainment of the highest good, _i.e._, blessedness and spiritual peace, one must live in harmony with oneself (ὁμολογουμενους ξῃν; δ᾽ εστι καθ᾽ ἑνα λογον και συμφωνον ξῃν.—_Consonanter vivere: hoc est secundum unam rationem et concordem sibi vivere._ Stob. Ecl. eth. L. ii., c. 7, p. 132. Also: Αρετην διαθεσιν ειναι ψυχης συμφωνον ἑαυτῃ περι ὁλον τον βιον. _Virtutem esse animi affectiomem secum per totam vitam consentientem_, _ibid._, p. 104.) Now this was only possible for a man if he determined himself entirely rationally, according to concepts, not according to changing impressions and moods; since, however, only the maxims of our conduct, not the consequences nor the outward circumstances, are in our power, in order to be always consistent we must set before us as our aim only the maxims and not the consequences and circumstances, and thus again a doctrine of virtue is introduced.

But the ethical principle of Zeno—to live in harmony with oneself—appeared even to his immediate successors to be too formal and empty. They therefore gave it material content by the addition—“to live in harmony with nature” (ὁμολογουμενως τῃ φυσει ζῃν), which, as Stobæus mentions in another place, was first added by Kleanthes, and extended the matter very much on account of the wide sphere of the concept and the vagueness of the expression. For Kleanthes meant the whole of nature in general, while Chrysippus meant human nature in particular (Diog. Laert., 7, 89). It followed that what alone was adapted to the latter was virtue, just as the satisfaction of animal desires was adapted to animal natures; and thus ethics had again to be forcibly united to a doctrine of virtue, and in some way or other established through physics. For the Stoics always aimed at unity of principle, as for them God and the world were not dissevered.

The ethical system of Stoicism, regarded as a whole, is in fact a very valuable and estimable attempt to use the great prerogative of man, reason, for an important and salutary end; to raise him above the suffering and pain to which all life is exposed, by means of a maxim—

“_Qua ratione queas traducere leniter œvum:_
_Ne te semper inops agitet vexetque cupido,_
_Ne pavor et rerum mediocriter utilium spes,_”

and thus to make him partake, in the highest degree, of the dignity which belongs to him as a rational being, as distinguished from the brutes; a dignity of which, in this sense at any rate, we can speak, though not in any other. It is a consequence of my view of the ethical system of Stoicism that it must be explained at the part of my work at which I consider what reason is and what it can do. But although it may to a certain extent be possible to attain that end through the application of reason, and through a purely rational system of ethics, and although experience shows that the happiest men are those purely rational characters commonly called practical philosophers,—and rightly so, because just as the true, that is, the theoretical philosopher carries life into the concept, they carry the concept into life,—yet it is far from the case that perfection can be attained in this way, and that the reason, rightly used, can really free us from the burden and sorrow of life, and lead us to happiness. Rather, there lies an absolute contradiction in wishing to live without suffering, and this contradiction is also implied in the commonly used expression, “blessed life.” This will become perfectly clear to whoever comprehends the whole of the following exposition. In this purely rational system of ethics the contradiction reveals itself thus, the Stoic is obliged in his doctrine of the way to the blessed life (for that is what his ethical system always remains) to insert a recommendation of suicide (as among the magnificent ornaments and apparel of Eastern despots there is always a costly vial of poison) for the case in which the sufferings of the body, which cannot be philosophised away by any principles or syllogistic reasonings, are paramount and incurable; thus its one aim, blessedness, is rendered vain, and nothing remains as a mode of escape from suffering except death; in such a case then death must be voluntarily accepted, just as we would take any other medicine. Here then a marked antagonism is brought out between the ethical system of Stoicism and all those systems referred to above which make virtue in itself directly, and accompanied by the most grievous sorrows, their aim, and will not allow a man to end his life in order to escape from suffering. Not one of them, however, was able to give the true reason for the rejection of suicide, but they laboriously collected illusory explanations from all sides: the true reason will appear in the Fourth Book in the course of the development of our system. But the antagonism referred to reveals and establishes the essential difference in fundamental principle between Stoicism, which is just a special form of endæmonism, and those doctrines we have mentioned, although both are often at one in their results, and are apparently related. And the inner contradiction referred to above, with which the ethical system of Stoicism is affected even in its fundamental thought, shows itself further in the circumstance that its ideal, the Stoic philosopher, as the system itself represents him, could never obtain life or inner poetic truth, but remains a wooden, stiff lay-figure of which nothing can be made. He cannot himself make use of his wisdom, and his perfect peace, contentment, and blessedness directly contradict the nature of man, and preclude us from forming any concrete idea of him. When compared with him, how entirely different appear the overcomers of the world, and voluntary hermits that Indian philosophy presents to us, and has actually produced; or indeed, the holy man of Christianity, that excellent form full of deep life, of the greatest poetic truth, and the highest significance, which stands before us in perfect virtue, holiness, and sublimity, yet in a state of supreme suffering.(26)

SECOND BOOK. THE WORLD AS WILL.

First Aspect. The Objectification Of The Will.

Nos habitat, non tartara, sed nec sidera coeli:
Spiritus, in nobis qui viget, illa facit.

§ 17. In the first book we considered the idea merely as such, that is, only according to its general form. It is true that as far as the abstract idea, the concept, is concerned, we obtained a knowledge of it in respect of its content also, because it has content and meaning only in relation to the idea of perception, without which it would be worthless and empty. Accordingly, directing our attention exclusively to the idea of perception, we shall now endeavour to arrive at a knowledge of its content, its more exact definition, and the forms which it presents to us. And it will specially interest us to find an explanation of its peculiar significance, that significance which is otherwise merely felt, but on account of which it is that these pictures do not pass by us entirely strange and meaningless, as they must otherwise do, but speak to us directly, are understood, and obtain an interest which concerns our whole nature.

We direct our attention to mathematics, natural science, and philosophy, for each of these holds out the hope that it will afford us a part of the explanation we desire. Now, taking philosophy first, we find that it is like a monster with many heads, each of which speaks a different language. They are not, indeed, all at variance on the point we are here considering, the significance of the idea of perception. For, with the exception of the Sceptics and the Idealists, the others, for the most part, speak very much in the same way of an _object_ which constitutes the _basis_ of the idea, and which is indeed different in its whole being and nature from the idea, but yet is in all points as like it as one egg is to another. But this does not help us, for we are quite unable to distinguish such an object from the idea; we find that they are one and the same; for every object always and for ever presupposes a subject, and therefore remains idea, so that we recognised objectivity as belonging to the most universal form of the idea, which is the division into subject and object. Further, the principle of sufficient reason, which is referred to in support of this doctrine, is for us merely the form of the idea, the orderly combination of one idea with another, but not the combination of the whole finite or infinite series of ideas with something which is not idea at all, and which cannot therefore be presented in perception. Of the Sceptics and Idealists we spoke above, in examining the controversy about the reality of the outer world.

If we turn to mathematics to look for the fuller knowledge we desire of the idea of perception, which we have, as yet, only understood generally, merely in its form, we find that mathematics only treats of these ideas so far as they fill time and space, that is, so far as they are quantities. It will tell us with the greatest accuracy the how-many and the how-much; but as this is always merely relative, that is to say, merely a comparison of one idea with others, and a comparison only in the one respect of quantity, this also is not the information we are principally in search of.

Lastly, if we turn to the wide province of natural science, which is divided into many fields, we may, in the first place, make a general division of it into two parts. It is either the description of forms, which I call _Morphology_, or the explanation of changes, which I call _Etiology_. The first treats of the permanent forms, the second of the changing matter, according to the laws of its transition from one form to another. The first is the whole extent of what is generally called natural history. It teaches us, especially in the sciences of botany and zoology, the various permanent, organised, and therefore definitely determined forms in the constant change of individuals; and these forms constitute a great part of the content of the idea of perception. In natural history they are classified, separated, united, arranged according to natural and artificial systems, and brought under concepts which make a general view and knowledge of the whole of them possible. Further, an infinitely fine analogy both in the whole and in the parts of these forms, and running through them all (_unité de plan_), is established, and thus they may be compared to innumerable variations on a theme which is not given. The passage of matter into these forms, that is to say, the origin of individuals, is not a special part of natural science, for every individual springs from its like by generation, which is everywhere equally mysterious, and has as yet evaded definite knowledge. The little that is known on the subject finds its place in physiology, which belongs to that part of natural science I have called etiology. Mineralogy also, especially where it becomes geology, inclines towards etiology, though it principally belongs to morphology. Etiology proper comprehends all those branches of natural science in which the chief concern is the knowledge of cause and effect. The sciences teach how, according to an invariable rule, one condition of matter is necessarily followed by a certain other condition; how one change necessarily conditions and brings about a certain other change; this sort of teaching is called _explanation_. The principal sciences in this department are mechanics, physics, chemistry, and physiology.

If, however, we surrender ourselves to its teaching, we soon become convinced that etiology cannot afford us the information we chiefly desire, any more than morphology. The latter presents to us innumerable and infinitely varied forms, which are yet related by an unmistakable family likeness. These are for us ideas, and when only treated in this way, they remain always strange to us, and stand before us like hieroglyphics which we do not understand. Etiology, on the other hand, teaches us that, according to the law of cause and effect, this particular condition of matter brings about that other particular condition, and thus it has explained it and performed its part. However, it really does nothing more than indicate the orderly arrangement according to which the states of matter appear in space and time, and teach in all cases what phenomenon must necessarily appear at a particular time in a particular place. It thus determines the position of phenomena in time and space, according to a law whose special content is derived from experience, but whose universal form and necessity is yet known to us independently of experience. But it affords us absolutely no information about the inner nature of any one of these phenomena: this is called a _force of nature_, and it lies outside the province of causal explanation, which calls the constant uniformity with which manifestations of such a force appear whenever their known conditions are present, a _law of nature_. But this law of nature, these conditions, and this appearance in a particular place at a particular time, are all that it knows or ever can know. The force itself which manifests itself, the inner nature of the phenomena which appear in accordance with these laws, remains always a secret to it, something entirely strange and unknown in the case of the simplest as well as of the most complex phenomena. For although as yet etiology has most completely achieved its aim in mechanics, and least completely in physiology, still the force on account of which a stone falls to the ground or one body repels another is, in its inner nature, not less strange and mysterious than that which produces the movements and the growth of an animal. The science of mechanics presupposes matter, weight, impenetrability, the possibility of communicating motion by impact, inertia and so forth as ultimate facts, calls them forces of nature, and their necessary and orderly appearance under certain conditions a law of nature. Only after this does its explanation begin, and it consists in indicating truly and with mathematical exactness, how, where and when each force manifests itself, and in referring every phenomenon which presents itself to the operation of one of these forces. Physics, chemistry, and physiology proceed in the same way in their province, only they presuppose more and accomplish less. Consequently the most complete etiological explanation of the whole of nature can never be more than an enumeration of forces which cannot be explained, and a reliable statement of the rule according to which phenomena appear in time and space, succeed, and make way for each other. But the inner nature of the forces which thus appear remains unexplained by such an explanation, which must confine itself to phenomena and their arrangement, because the law which it follows does not extend further. In this respect it may be compared to a section of a piece of marble which shows many veins beside each other, but does not allow us to trace the course of the veins from the interior of the marble to its surface. Or, if I may use an absurd but more striking comparison, the philosophical investigator must always have the same feeling towards the complete etiology of the whole of nature, as a man who, without knowing how, has been brought into a company quite unknown to him, each member of which in turn presents another to him as his friend and cousin, and therefore as quite well known, and yet the man himself, while at each introduction he expresses himself gratified, has always the question on his lips: “But how the deuce do I stand to the whole company?”

Thus we see that, with regard to those phenomena which we know only as our ideas, etiology can never give us the desired information that shall carry us beyond this point. For, after all its explanations, they still remain quite strange to us, as mere ideas whose significance we do not understand. The causal connection merely gives us the rule and the relative order of their appearance in space and time, but affords us no further knowledge of that which so appears. Moreover, the law of causality itself has only validity for ideas, for objects of a definite class, and it has meaning only in so far as it presupposes them. Thus, like these objects themselves, it always exists only in relation to a subject, that is, conditionally; and so it is known just as well if we start from the subject, _i.e._, _a priori_, as if we start from the object, _i.e._, _a posteriori_. Kant indeed has taught us this.

But what now impels us to inquiry is just that we are not satisfied with knowing that we have ideas, that they are such and such, and that they are connected according to certain laws, the general expression of which is the principle of sufficient reason. We wish to know the significance of these ideas; we ask whether this world is merely idea; in which case it would pass by us like an empty dream or a baseless vision, not worth our notice; or whether it is also something else, something more than idea, and if so, what. Thus much is certain, that this something we seek for must be completely and in its whole nature different from the idea; that the forms and laws of the idea must therefore be completely foreign to it; further, that we cannot arrive at it from the idea under the guidance of the laws which merely combine objects, ideas, among themselves, and which are the forms of the principle of sufficient reason.

Thus we see already that we can never arrive at the real nature of things from without. However much we investigate, we can never reach anything but images and names. We are like a man who goes round a castle seeking in vain for an entrance, and sometimes sketching the façades. And yet this is the method that has been followed by all philosophers before me.

§ 18. In fact, the meaning for which we seek of that world which is present to us only as our idea, or the transition from the world as mere idea of the knowing subject to whatever it may be besides this, would never be found if the investigator himself were nothing more than the pure knowing subject (a winged cherub without a body). But he is himself rooted in that world; he finds himself in it as an _individual_, that is to say, his knowledge, which is the necessary supporter of the whole world as idea, is yet always given through the medium of a body, whose affections are, as we have shown, the starting-point for the understanding in the perception of that world. His body is, for the pure knowing subject, an idea like every other idea, an object among objects. Its movements and actions are so far known to him in precisely the same way as the changes of all other perceived objects, and would be just as strange and incomprehensible to him if their meaning were not explained for him in an entirely different way. Otherwise he would see his actions follow upon given motives with the constancy of a law of nature, just as the changes of other objects follow upon causes, stimuli, or motives. But he would not understand the influence of the motives any more than the connection between every other effect which he sees and its cause. He would then call the inner nature of these manifestations and actions of his body which he did not understand a force, a quality, or a character, as he pleased, but he would have no further insight into it. But all this is not the case; indeed the answer to the riddle is given to the subject of knowledge who appears as an individual, and the answer is _will_. This and this alone gives him the key to his own existence, reveals to him the significance, shows him the inner mechanism of his being, of his action, of his movements. The body is given in two entirely different ways to the subject of knowledge, who becomes an individual only through his identity with it. It is given as an idea in intelligent perception, as an object among objects and subject to the laws of objects. And it is also given in quite a different way as that which is immediately known to every one, and is signified by the word _will_. Every true act of his will is also at once and without exception a movement of his body. The act of will and the movement of the body are not two different things objectively known, which the bond of causality unites; they do not stand in the relation of cause and effect; they are one and the same, but they are given in entirely different ways,—immediately, and again in perception for the understanding. The action of the body is nothing but the act of the will objectified, _i.e._, passed into perception. It will appear later that this is true of every movement of the body, not merely those which follow upon motives, but also involuntary movements which follow upon mere stimuli, and, indeed, that the whole body is nothing but objectified will, _i.e._, will become idea. All this will be proved and made quite clear in the course of this work. In one respect, therefore, I shall call the body the _objectivity of will_; as in the previous book, and in the essay on the principle of sufficient reason, in accordance with the one-sided point of view intentionally adopted there (that of the idea), I called it _the immediate object_. Thus in a certain sense we may also say that will is the knowledge _a priori_ of the body, and the body is the knowledge _a posteriori_ of the will. Resolutions of the will which relate to the future are merely deliberations of the reason about what we shall will at a particular time, not real acts of will. Only the carrying out of the resolve stamps it as will, for till then it is never more than an intention that may be changed, and that exists only in the reason _in abstracto_. It is only in reflection that to will and to act are different; in reality they are one. Every true, genuine, immediate act of will is also, at once and immediately, a visible act of the body. And, corresponding to this, every impression upon the body is also, on the other hand, at once and immediately an impression upon the will. As such it is called pain when it is opposed to the will; gratification or pleasure when it is in accordance with it. The degrees of both are widely different. It is quite wrong, however, to call pain and pleasure ideas, for they are by no means ideas, but immediate affections of the will in its manifestation, the body; compulsory, instantaneous willing or not-willing of the impression which the body sustains. There are only a few impressions of the body which do not touch the will, and it is through these alone that the body is an immediate object of knowledge, for, as perceived by the understanding, it is already an indirect object like all others. These impressions are, therefore, to be treated directly as mere ideas, and excepted from what has been said. The impressions we refer to are the affections of the purely objective senses of sight, hearing, and touch, though only so far as these organs are affected in the way which is specially peculiar to their specific nature. This affection of them is so excessively weak an excitement of the heightened and specifically modified sensibility of these parts that it does not affect the will, but only furnishes the understanding with the data out of which the perception arises, undisturbed by any excitement of the will. But every stronger or different kind of affection of these organs of sense is painful, that is to say, against the will, and thus they also belong to its objectivity. Weakness of the nerves shows itself in this, that the impressions which have only such a degree of strength as would usually be sufficient to make them data for the understanding reach the higher degree at which they influence the will, that is to say, give pain or pleasure, though more often pain, which is, however, to some extent deadened and inarticulate, so that not only particular tones and strong light are painful to us, but there ensues a generally unhealthy and hypochondriacal disposition which is not distinctly understood. The identity of the body and the will shows itself further, among other ways, in the circumstance that every vehement and excessive movement of the will, _i.e._, every emotion, agitates the body and its inner constitution directly, and disturbs the course of its vital functions. This is shown in detail in “Will in Nature,” p. 27 of the second edition and p. 28 of the third.

Lastly, the knowledge which I have of my will, though it is immediate, cannot be separated from that which I have of my body. I know my will, not as a whole, not as a unity, not completely, according to its nature, but I know it only in its particular acts, and therefore in time, which is the form of the phenomenal aspect of my body, as of every object. Therefore the body is a condition of the knowledge of my will. Thus, I cannot really imagine this will apart from my body. In the essay on the principle of sufficient reason, the will, or rather the subject of willing, is treated as a special class of ideas or objects. But even there we saw this object become one with the subject; that is, we saw it cease to be an object. We there called this union the miracle κατ᾽ εξοχην, and the whole of the present work is to a certain extent an explanation of this. So far as I know my will specially as object, I know it as body. But then I am again at the first class of ideas laid down in that essay, _i.e._, real objects. As we proceed we shall see always more clearly that these ideas of the first class obtain their explanation and solution from those of the fourth class given in the essay, which could no longer be properly opposed to the subject as object, and that, therefore, we must learn to understand the inner nature of the law of causality which is valid in the first class, and of all that happens in accordance with it from the law of motivation which governs the fourth class.