Historicaly, epistemology has been ahistorical. That is to say, epistemologists have sought to fix the universal and necessary conditions of any knowledge whatever, or to establish the essential nature of the human mind. Thus, whether empiricist or rationalist, realist or phenomenalist, traditional epistemologies have shared a common essentialism. What made such epistemologies different were alternative accounts of what are the fixed, essential modes of the acquisition of knowledge, or what are the universal and unchanging structures of the human mind. Essentialism merged with foundationalism or justificationism just to the extent that putatively descriptive accounts of the modes of the acquisition of knowledge were tacitly normative (i.e., in that it was knowledge, and not mere belief, or habit, or phantasms of the imagination which resulted from the proper working, or the proper correction, of these cognitive procedures.) Or else, essentialism was openly justificationist, in the converse procedure of constructing just those accounts of, say, perception or cognition such that the normal exercise of these faculties would generate knowledge, or make truth attainable.