Abstract
Presents Nietzsche's critical reflections directed at traditional metaphysical categories such as the external world, substance, causation, and self. Targeted theories include the doctrine of substance qua substratum for properties; the Lockean ontology of powers inherent in external objects; the construal of the self as either mental substance or transcendental subjects; atomism; and the belief in the explanatory powers of Newtonian force. It is argued that there is a pervasive general line of scepticism in Nietzsche's later thought concerning the possibility of knowledge as rationally justified true belief. The chapter concludes with a defence of Nietzsche's general scepticism against a variety of countervailing arguments.