a word to starting from mere qualitates occultæ, the elucidation of which was entirely given up, for they intended to build upon them, not to investigate them. Such an intention cannot, as we have already said, be carried out. But apart from this, such structures would always stand in the air. What is the use of explanations which ultimately refer us to something which is quite as unknown as the problem with which we started? Do we in the end understand more of the inner nature of these universal natural forces than of the inner nature of an animal? Is not the one as much a sealed book to us as the other? Unfathomable because it is without ground, because it is the content, that which the phenomenon is, and which can never be referred to the form, to the how, to the principle of sufficient reason. But we, who have in view not etiology but philosophy, that is, not relative but unconditioned knowledge of the real nature of the world, take the opposite course, and start from that which is immediately and most completely known to us, and fully and entirely trusted by us—that which lies nearest to us, in order to understand that which is known to us only at a distance, one-sidedly and indirectly. From the most powerful, most significant, and most distinct phenomenon we seek to arrive at an understanding of those that are less complete and weaker. With the exception of my own body, all things are known to me only on one side, that of the idea. Their inner nature remains hidden from me and a profound secret, even if I know all the causes from which their changes follow. Only by comparison with that which goes on in me if my body performs an action when I am influenced by a motive—only by comparison, I say, with what is the inner nature of my own changes determined by external reasons, can I obtain insight into the way in which these lifeless bodies change under the influence of causes, and so understand what is their inner nature. For the knowledge of the causes of the manifestation of this inner nature affords me merely the rule of its appearance in time and space, and nothing more. I can make this comparison because my body is the only object of which I know not merely the one side, that of the idea, but also the other side which is called will. Thus, instead of believing that I would better understand my own organisation, and then my own knowing and willing, and my movements following upon motives, if I could only refer them to movements due to electrical, chemical, and mechanical causes, I must, seeing that I seek philosophy and not etiology, learn to understand from my own movements following upon motives the inner nature of the simplest and commonest movements of an unorganised body which I see following upon causes. I must recognise the inscrutable forces which manifest themselves in all natural bodies as identical in kind with that which in me is the will, and as differing from it only in degree. That is to say, the fourth class of ideas given in the Essay on the Principle of Sufficient Reason must be the key to the knowledge of the inner nature of the first class, and by means of the law of motivation I must come to understand the inner meaning of the law of causation.
Spinoza (Epist. 62) says that if a stone which has been projected through the air had consciousness, it would believe that it was moving of its own will. I add to this only that the stone would be right. The impulse given it is for the stone what the motive is for me, and what in the case of the stone appears as cohesion, gravitation, rigidity, is in its inner nature the same as that which I recognise in myself as will, and what the stone also, if knowledge were given to it, would recognise as will. In the passage referred to, Spinoza had in view the necessity with which the stone flies, and he rightly desires to transfer this necessity to that of the particular act of will of a person. I, on the other hand, consider the inner being, which alone imparts meaning and validity to all real necessity (i.e., effect following upon a cause) as its presupposition. In the case of men this is called character; in the case of a stone it is called quality, but it is the same in both. When it is immediately known it is called will. In the stone it has the weakest, and in man the strongest degree of visibility, of objectivity. St. Augustine recognises, with a true instinct, this identity of the tendencies of all things with our own willing, and I cannot refrain from quoting his naïve account of the matter:—“Si pecora essemus, carnalem vitam et quod secundum sensum ejusdem est amaremus, idque esset sufficiens bonum nostrum, et secundum hoc si esset nobis bene, nihil aliud quæreremus. Item, si arbores essemus, nihil quidem sentientes motu amare possemus: verumtamen id quasi appetere videremur, quo feracius essemus, uberiusque fructuosæ. Si essemus lapides, aut fluctus, aut ventus, aut flamma, vel quid ejusmodi, sine ullo quidem sensu atque vita, non tamen nobis deesset quasi quidam nostrorum locorum atque ordinis appetitus. Nam velut amores corporum momenta sunt ponderum, sive deorsum gravitate, sive sursum levitate nitantur: ita enim corpus pondere, sicut animus amore fertur quocunque fertur” (De Civ. Dei, xi. 28).
It ought further to be mentioned that Euler saw that the inner nature of gravitation must ultimately be referred to an “inclination and desire” (thus will) peculiar to material bodies (in the 68th letter to the Princess). Indeed, it is just this that makes him averse to the conception of gravitation as it existed for Newton, and he is inclined to try a modification of it in accordance with the earlier Cartesian theory, and so to derive gravitation from the impact of an ether upon the bodies, as being “more rational and more suitable for persons who like clear and intelligible principles.” He wishes to banish attraction from physics as a qualitas occulta. This is only in keeping with the dead view of nature which prevailed at Euler's time as the correlative of the immaterial soul. It is only worth noticing because of its bearing upon the fundamental truth established by me, which even at that time this fine intellect saw glimmering in the distance. He hastened to turn in time, and then, in his anxiety at seeing all the prevalent fundamental views endangered, he sought safety in the old and already exploded absurdities.
We know that multiplicity in general is necessarily conditioned by space and time, and is only thinkable in them. In this respect they are called the principium individuationis. But we have found that space and time are forms of the principle of sufficient reason. In this principle all our knowledge a priori is expressed, but, as we showed above, this a priori knowledge, as such, only applies to the knowableness of things, not to the things themselves, i.e., it is only our form of knowledge, it is not a property of the thing-in-itself. The thing-in-itself is, as such, free from all forms of knowledge, even the most universal, that of being an object for the subject. In other words, the thing-in-itself is something altogether different from the idea. If, now, this thing-in-itself is the will, as I believe I have fully and convincingly proved it to be, then, regarded as such and apart from its manifestation, it lies outside time and space, and therefore knows no multiplicity, and is consequently one. Yet, as I have said, it is not one in the sense in which an individual or a concept is one, but as something to which the condition of the possibility of multiplicity, the principium individuationis, is foreign. The multiplicity of things in space and time, which collectively constitute the objectification of will, does not affect the will itself, which remains indivisible notwithstanding it. It is not the case that, in some way or other, a smaller part of will is in the stone and a larger part in the man, for the relation of part and whole belongs exclusively to space, and has no longer any meaning when we go beyond this form of intuition or perception. The more and the less have application only to the phenomenon of will, that is, its visibility, its objectification. Of this there is a higher grade in the plant than in the stone; in the animal a higher grade than in the plant: indeed, the passage of will into visibility, its objectification, has grades as innumerable as exist between the dimmest twilight and the brightest sunshine, the loudest sound and the faintest echo. We shall return later to the consideration of these grades of visibility which belong to the objectification of the will, to the reflection of its nature. But as the grades of its objectification do not directly concern the will itself, still less is it concerned by the multiplicity of the phenomena of these different grades, i.e., the multitude of individuals of each form, or the particular manifestations of each force. For this multiplicity is directly conditioned by time and space, into which the will itself never enters. The will reveals itself as completely and as much in one oak as in millions. Their number and multiplication in space and time has no meaning with regard to it, but only with regard to the multiplicity of individuals who know in space and time, and who are themselves multiplied and dispersed in these. The multiplicity of these individuals itself belongs not to the will, but only to its manifestation. We may therefore say that if, per impossibile, a single real existence, even the most insignificant, were to be entirely annihilated, the whole world would necessarily perish with it. The great mystic Angelus Silesius feels this when he says—
