ABSTRACT
Immanuel Kant's main philosophical achievement can be understood as reconciliation into a single theory of knowledge of elements of both rationalist and empiricist epistemo-logies. Kant's distinction between a phenomenal world, open to perception and to knowledge through scientific methods and concepts, and an unknowable noumenal world of free subjectivity is, of course, open to serious philosophical objections. The principal difficulty is that the resolution of the problem of free will and determinism requires a good deal to be said about the nature of the supposedly unknowable things-in-themselves. The Neo-Kantian movement which established itself in the dispersed academic centres of Germany from the 1860s onwards was initially hostile both to German idealist developments of Kant and to positivism, though the influence of positivism was at work in the tendency to relativise the distinction between noumena and phenomena or else to reject the notion of a noumenal world altogether.
