One might make a case about James being a scientist, however that's the sort of after the fact revision which Kuhn describes in Structure of Scientific Revolution.
But there is no way to make that claim about Kant and Critique of Pure Reason. The logic underpinning such an argument - that Kant's view of the mind does not match popular current scientific theories and therefor does not constitute science - would also place Newton's Principia outside the realm of Physics.
To suppose that the thrust of Kant's categories do not underpin modern psychology one would have to be the most radical of behaviorists. Modern psychology readily accepts that a person's experience of the world is largely shaped by the features of their mind - e.g. reframing.
As for what psychologists claim as their epistemological basis, I suspect that the rate at which psychologists would claim James as a predecessor is significantly greater than the rate at which planetary astronomers who would claim Giordano Bruno's work as their epistemological base.
"The logic underpinning such an argument - that Kant's view of the mind does not match popular current scientific theories and therefor does not constitute science - would also place Newton's Principia outside the realm of Physics."
That's an interesting parallel, but I think Newton/Kant is really apples/oranges (as it were). Kant's 'Copernican Revolution' notwithstanding, his <i>a priori</i> categories were highly speculative -- by definition -- and not really meant as a theoretical underpinning for a science of mind as much as an attempt to establish a reasonably defensible epistemology in the face of Hume's skepticism. Kant may have had hopes in a scientific direction, but in practice no scientist uses concrete, specific Kantian principles as a basis for research. Gestalt theory would be the closest attempt, but that's a pretty high-level appropriation. It had its day and retains some residual influence but certainly nothing on the order of Newton's fundamental laws in the world of physics.
But even if you consider Gestalt or some of the contemporary influence of phenomenology in certain psychological circles (and they are limited), the philosophical problems with Kant or James remain: Neither James' nor Kant's answers to Hume fully protect one from skepticism or solipsism. Husserl and his inheritors in the Phenomenological/Continental tradition fared better there, and certainly Husserl's entire endeavor was focused on Science and its epistemological problems -- but very little of the scientific community has done the difficult work of understanding Husserl. Kuhn/Popper/Lakatos it seems are much easier to digest.
Perhaps a better example here is the work of the empirical psychologists Fechner, Weber, Helmholtz, Wundt &c., respectively influenced by and reacting to Mach and Kant.
But there is no way to make that claim about Kant and Critique of Pure Reason. The logic underpinning such an argument - that Kant's view of the mind does not match popular current scientific theories and therefor does not constitute science - would also place Newton's Principia outside the realm of Physics.
To suppose that the thrust of Kant's categories do not underpin modern psychology one would have to be the most radical of behaviorists. Modern psychology readily accepts that a person's experience of the world is largely shaped by the features of their mind - e.g. reframing.
[http://en.wikipedia.org/wiki/Reframing]
As for what psychologists claim as their epistemological basis, I suspect that the rate at which psychologists would claim James as a predecessor is significantly greater than the rate at which planetary astronomers who would claim Giordano Bruno's work as their epistemological base.