just at this time here, and at this place now; it is clear that with their assistance we can never penetrate to the inner nature of things. There always remains something which no explanation can venture to attack, but which it always presupposes; the forces of nature, the definite mode of operation of things, the quality and character of every phenomenon, that which is without ground, that which does not depend upon the form of the phenomenal, the principle of sufficient reason, but is something to which this form in itself is foreign, something which has yet entered this form, and now appears according to its law, a law, however, which only determines the appearance, not that which appears, only the how, not the what, only the form, not the content. Mechanics, physics, and chemistry teach the rules and laws according to which the forces of impenetrability, gravitation, rigidity, fluidity, cohesion, elasticity, heat, light, affinity, magnetism, electricity, &c., operate; that is to say, the law, the rule which these forces observe whenever they enter time and space. But do what we will, the forces themselves remain qualitates occultæ. For it is just the thing-in-itself, which, because it is manifested, exhibits these phenomena, which are entirely different from itself. In its manifestation, indeed, it is completely subordinated to the principle of sufficient reason as the form of the idea, but it can never itself be referred to this form, and therefore cannot be fully explained etiologically, can never be completely fathomed. It is certainly perfectly comprehensible so far as it has assumed that form, that is, so far as it is phenomenon, but its inner nature is not in the least explained by the fact that it can thus be comprehended. Therefore the more necessity any knowledge carries with it, the more there is in it of that a which cannot be otherwise thought or presented in perception — as, for example, space-relations — the clearer and more sufficing then it is, the less pure objective content it has, or the less reality, properly so called, is
