Alois Riehl’s Epistemological Argument for Realism about Things in Themselves

Riehl was one of the leading figures in the neo-Kantian movement and the founder of critical realism. This view was characterised by a realist interpretation of Kant’s notion of a thing in itself based on a physiological account of sensation: although Riehl agreed with Kant that things in themselves are unknowable through reason alone, he maintained that such things do affect empirical intuitions and manifest themselves indirectly in empirical knowledge. This paper offers a discussion of Riehl’s argument by taking the example of his account of empirical factors in the representation of space. According to Riehl, Helmholtz’s empiricist approach to spatial intuition offered an argument for the accessibility of external reality. In order to clarify the position of the critical realist, I compare Riehl’s argument with Helmholtz’s own account of objectivity in terms of repeatability of measurement operations.