But in consequence of that unduly wide view in abstract thought of the conception cause, which was considered above, it has been confounded with the conception of force. This is something completely different from the cause, but yet is that which imparts to every cause its causality, i.e., the capability of producing an effect. I have explained this fully and thoroughly in the second book of the first volume, also in "The Will in Nature," and finally also in the second edition of the essay on the principle of sufficient reason, § 20, p. 44 (third edition, p. 45). This confusion is to be found in its most aggravated form in Maine de Biran's book mentioned above, and this is dealt with more fully in the place last referred to; but apart from this it is also very common; for example, when people seek for the cause of any original force, such as gravitation. Kant himself (Über den Einzig Möglichen Beweisgrund, vol. i. p. 211-215 of Rosenkranz's edition) calls the forces of nature "efficient causes," and says "gravity is a cause." Yet it is impossible to see to the bottom of his thought so long as force and cause are not distinctly recognised as completely different. But the use of abstract conceptions leads very easily to their confusion if the consideration of their origin is set aside. The knowledge of causes and effects, always perceptive, which rests on the form of the understanding, is neglected in order to stick to the abstraction cause. In this way alone is the conception of causality, with all its simplicity, so very frequently wrongly apprehended. Therefore even in Aristotle ("Metaph.," iv. 2) we find causes divided into four classes which are utterly falsely, and indeed crudely conceived. Compare with it my classification of causes as set forth for the first time in my essay on sight and colour, chap. 1, and touched upon briefly in the sixth paragraph of the first volume of the present work, but expounded at full length in my prize essay on the freedom of the will, p. 30-33. Two things in nature remain untouched by that chain of causality which stretches into
