The Terms of Reference of the Classical Theory of Knowledge Included the Assumption that There WAS a Right and Wrong Way of Going about the Acquisition of Knowledge

Culture (which Descartes named ‘custom and example’) was, in the Cartesian programme, the source of error. That is of course an abomination to those imbued with the postmodernist spirit. What Descartes and his successors said, in effect, was that there are an awful lot of meanings and opinions about, that they cannot all be right, and that we’d better find, and justify, a yardstick which will sort out the sheep from the goats. For Descartes, the yardstick involved the exclusive use of clear and distinct meanings, so clear and distinct as to impose their authority on all minds sober and determined enough to heed them, irrespective of their culture. The path to truth lay through voluntary cultural exile. The terms of reference of the central, classical theory of knowledge included the assumption that there was a right and wrong way of going about the acquisition of knowledge: the problem was to find the difference, and, when it was located, to justify it. The contemporary idea is that there is no difference, that to set up ranking between kinds of knowledge is morally and politically wicked, rather like setting up one skin colour above another (with more than a hint that perhaps the two discriminations were linked to each other).

--Ernest Gellner, Postmodernism, Reason and Religion (London: Routledge Taylor and Francis e-Library, 2003), 37-38.