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Schopenhauer's philosophy

The philosophy of Arthur Schopenhauer owes much to the thought of Kant and to that of the German idealists, which he nevertheless strongly criticizes. Schopenhauer maintains Kant's idealist epistemology which sees even space, time and causality are mere mental representations (vorstellungen) conditioned by the subjective mind. However, he replaces Kant's unknowable thing-in-itself with an absolute reality underlying all ideas that is a single irrational Will, a view that he saw as directly opposed to Hegel's rational Spirit. This philosophy is laid out in The World as Will and Representation (WWR 1818, 2nd ed. 1844).

Schopenhauer accepts Kant's view that there can be no appearances without there being something which appears. However, unlike Kant, Schopenhauer writes that "we have immediate cognition of the thing in itself when it appears to us as our own body". (WWR §6, pp. 40–1). Schopenhauer argues that, even though we do experience our own bodies through the categories of space, time and causality, we also experience it in another more direct and internal way through the experience of willing. This immediate experience reveals that it is will alone which "gives him the key to his own appearance, reveals to him the meaning and shows him the inner workings of his essence, his deeds, his movements" (WWR §18, p. 124). Thus, for Schopenhauer, it is desire, a "dark, dull driving", which is at the root of action, not reason. Furthermore, since this is the only form of insight we have of the inner essence of any reality, we must apply this insight "to appearances in the inorganic world as well." Schopenhauer compares willing with many natural forces. As such, Will is "a name signifying the being in itself of every thing in the world and the sole kernel of every appearance" (WWR §23, pp. 142–3).

Because irrational Willing is the most foundational reality, life is filled with frustration, irrationality and disappointment. This is the metaphysical foundation of Schopenhauer's pessimistic philosophy of life. The best we can hope for is to deny and try to escape (however briefly) the incessant force of the Will, through art, aesthetic experience, asceticism, and compassion.