were right, not only in their sense but also in ours, when they made the paradoxical assertion already referred to in chapter 4: Matter itself is not extended, consequently it is incorporeal. For space, which is our form of perception, imparts extension to matter, and corporeal existence consists in acting, which depends upon causality, and consequently upon the form of our understanding. On the other hand every definite property, thus everything empirical in matter, even gravity, depends upon that which only becomes visible by means of matter, the thing in itself, the will Gravity is yet the lowest of all grades of the objectification of the will; therefore it appears in all matter without exception, thus is inseparable from matter in general. Yet, just because it is a manifestation of the will, it belongs to knowledge a posteriori, not to knowledge a priori. Therefore we can always picture to ourselves matter without weight, but not without extension, repulsive force, and stability, for then it would be without impenetrability, and consequently would not occupy space, i.e., it would be without the power of acting; but the nature of matter as such just consists in acting, i.e., in causality in general; and causality depends upon the a priori form of our understanding, and therefore cannot be thought away.
Matter is accordingly the will itself, but no longer in itself, but so far as it is perceived, i.e., assumes the form of the objective idea. Thus what objectively is matter is subjectively will. Exactly corresponding to this, as was proved above, our body is just the visibility, objectivity of our will, and so also every body is the objectivity of the will at some one of its grades. Whenever the will exhibits itself to objective knowledge it enters into the forms of perception of the intellect, time, space, and causality. But on account of this it exists at once as a material object. We can present to our minds form without matter, but not the reverse; because matter deprived of form would be the will itself, and the will
