The cause of its having developed itself precisely in this manner and no other, lies partly in itself, because it is this particular power and no other; and partly in the circumstances under which it developes itself. Both these,—the inward determination of a power by itself, and its outward determination by circumstances,—must be united in order to produce a change. The latter,—the circumstances, the passive condition of things,—can of itself produce no change, for it contains within it the opposite of all change,—inert existence. The former,—the power,—is wholly determined, for only on this condition is it conceivable; but its determination is completed only through the circumstances under which it is developed. I can conceive of a power, it can have an existence for me, only in so far as I can perceive an effect proceeding from it; an inactive power,—which should yet be a power and not an inert thing,—is wholly inconceivable. Every affect, however, is determined,—and since the effect is but the expression, but another mode of the activity itself,—the active power is determined in its activity, and the ground of this determination lies partly in itself, because it can only be conceived of as a particular and definite power; partly out of itself, because its own determination can only be conceived of as conditioned by something else.
A flower has sprung out of the earth, and I infer from thence a formative power in Nature. Such a formative power exists for me only so far as this flower and others, plants, and animals exist for me:—I can describe this power only through its effects, and it is to me no more than the producing cause of such effects,—the generative principle of flowers, plants, animals,
