 A return to an anti-psychologistic Kant was the Neo-Kantians’ solution to what the historian Herbert Schnädelbach (1984: 5) called the “identity crisis” that faced philosophy in the middle of the nineteenth century. Given the collapse of the conception of philosophy shared by post-Kantian speculative idealists, and the concurrent spectacular advances made in the sciences, philosophers were left questioning what (if anything) was left as the distinctive subject matter and method of philosophy (Beiser 2014a: Ch.1). In particular, in opposing psychologism, the Neo-Kantians were staking out a conception of philosophy that avoids the naturalism defended by many German philosophers in the decades after Hegel’s death (Cassirer 1912). According to naturalistic conceptions of philosophy, the method of philosophy is in fact not distinguishable from that of natural science, and the theory of knowledge just becomes applied empirical psychology. Nevertheless, the Neo-Kantians shared with these naturalistic philosophers a deep distrust of speculative metaphysics: they denied that philosophy could deliver knowledge of the supersensible, could deduce facts of the special sciences from a priori principles knowable in some special philosophical way, or that philosophy could even be done in ignorance of the results of the sciences.