"[Kant's] most permanent contribution may be his distinction between his own philosophical project in the Deduction and the aims of empirical, natural-scientific psychology. That distinction and its descendants, such as the more recent distinction between the 'logical space of reasons' and the 'logical space of causes [Rorty] mark out a fundamental divide between the natural science of mental processes and investigation of the logical, conceptual, and justificatory order of thought. The latter division remains controversial, which is to say that the question of the ultimate viability of the Kantian distinction remains contested."
Gary Hatfield, "Empirical, rational and transcendental psychology: Psychology as science and as philosophy", in The Cambridge Companion to Kant, Ed Paul Guyer, Cambridge, 1992. Quotation from page 223.