 Psychology, as understood by Mill, is what in An Essay on Metaphysics Collingwood calls a “pseudo-science of thought” (EM 1998: 142) because it fails to acknowledge that the concept of mind is, in the words of Gallie (1956), an essentially contested concept that (like “cause”, “action”, “science”, and “the past”) needs to be disambiguated. This is not to say that empirical psychology is not a legitimate scientific pursuit, but that the subject matter of empirical psychology and that of history are not the same and that the attempt to capture the mind by the methods of empirical science should be denounced as the attempt by one form of knowledge to trespass on the territory of another.