In unorganised nature the will objectifies itself primarily in the universal forces, and only by means of these in the phenomena of the particular things which are called forth by causes. In § 26 of the first volume I have fully explained the relation between cause, force of nature, and will as thing in itself. One sees from that explanation that metaphysics never interrupts the course of physics, but only takes up the thread where physics leaves it, at the original forces in which all causal explanation has its limits. Only here does the metaphysical explanation from the will as the thing in itself begin. In the case of every physical phenomenon, of every _change_ of material things, its cause is primarily to be looked for; and this cause is just such a particular _change_ which has appeared immediately before it. Then, however, the original force of nature is to be sought by virtue of which this cause was capable of acting. And first of all the _will_ is to be recognised as the inner nature of this force in opposition to its manifestation. Yet the will shows itself just as directly in the fall of a stone as in the action of the man; the difference is only that its particular manifestation is in the one case called forth by a motive, in the other by a mechanically acting cause, for example, the taking away of what supported the stone; yet in both cases with equal necessity; and that in the one case it depends upon an individual character, in the other upon an universal force of nature. This identity of what is fundamentally essential is even made palpable to the senses. If, for instance, we carefully observe a body which has lost its equilibrium, and on account of its special form rolls back and forward for a long time till it finds its centre of gravity again, a certain appearance of life forces itself upon us, and we directly feel that something analogous to the foundation of life is also active here. This is certainly the universal force of nature, which, however, in itself identical with the _will_, becomes here, as it were, the soul of a very brief _quasi_ life. Thus what is identical in the two extremes of the manifestation of the will makes itself faintly known here even to direct perception, in that this raises a feeling in us that here also something entirely original, such as we only know in the acts of our own will, directly succeeded in manifesting itself.