We argue that Kant’s views about consciousness, the mind—body problem and the status of psychology as a science all differ drastically from the way in which these topics are conjoined in present debates about the prominent idea of a science of consciousness. Kant never used the concept of consciousness in the now dominant sense of phenomenal qualia; his discussions of the mind—body problem center not on the reducibility of mental properties but of substances; and his views about the possibility of psychology as a science did not employ the requirement of a mechanistic explanation, but of a quantification of phenomena. This shows strikingly how deeply philosophical problems and conceptions can change even if they look similar on the surface.