The Blind Will as Thing-in-Itself

Schopenhauer's path to the thing-in-itself runs through our own bodies. Each of us has access to one object from two sides simultaneously: the body as it appears in outer perception (a physical object in space and time) and the body as it is known from within — as felt, willed, acted. When I raise my arm, the movement appears in representation as a physical event; but I also know it immediately as an act of will. The willing and the bodily movement are not cause and effect but one and the same event seen from two angles. The body is will made visible.

This insight, once achieved, can be extended to the whole of nature by analogy. The drive of gravity, the growth of plants, the instinct of animals, the beating of the heart — all are expressions of the same thing we know in ourselves as will. Schopenhauer does not argue that rocks have conscious intentions; rather, he reverses the picture. Our own willed actions, when stripped of the intellectual veneer added by consciousness, are revealed as the same blind, impulsive striving we can identify throughout the natural world. Will is not a high metaphysical concept borrowed from human psychology and projected onto nature; it is the deeper reality of which human psychology is the most transparent instance.

The Will that underlies all things has no goal, no end, no object it is trying to attain that, once attained, would bring satisfaction. It simply strives — endlessly, blindly, pointlessly. Each local satisfaction immediately generates a new lack. The individual organism exists only as a temporary vehicle for the Will's striving, discarded when it has served its reproductive purpose. This is Schopenhauer's metaphysical foundation for his pessimism: the inner nature of the world is a hunger that cannot be fed, an energy that cannot be exhausted, a suffering that cannot be finally resolved — only, at most, escaped.

Book Two of The World as Will and Representation (1818) develops the doctrine of the will as thing-in-itself. The analogy of the body as the "key" to the will is presented in §18–19. The extension of will to all of nature, including inorganic processes, is elaborated in On the Will in Nature (1836).