Noumenon, Vitalism, Pessimism

Schopenhauer finds little joy in what is his perhaps most significant philosophical innovation.  That innovation is the product of an inversion of Kant's concept of the relation between Physics and Biology, i. e. in which Kant derives the latter from the former via a heuristic hypothesis.  In contrast, for Schopenhauer, Biology, with its principle of Will, is fundamental, with respect to which Physics is a representation.  His system can thus be classified as 'Vitalistic', and as a forerunner of Bergson's and Nietzsche's, in that respect.  However, Will is not merely fundamental for Schopenhauer, it is noumenal, which means that the latter realm is constituted by an incessant striving that is the source of human suffering.  Thus, his inversion displaces from that realm Kant's God who is a source of a positive answer to the question 'What can I hope for?', resulting in a doctrine that he characterizes as 'Pessimism'.