Proceeding from the transcendental idealism of Immanuel Kant, Schopenhauer developed an atheistic metaphysical and ethical system that has been described as an exemplary manifestation of philosophical pessimism, rejecting the contemporaneous post-Kantian philosophies of German idealism. Schopenhauer was among the first thinkers in Western philosophy to share and affirm significant tenets of Eastern philosophy (e.g., asceticism, the world-as-appearance), having initially arrived at similar conclusions as the result of his own philosophical work.