It was Marx and Marxists who were the inventers of "standpoint epistemology," the idea that one's "social" position–for Marxists, "class," for later writers, race, gender, and so on–exercises an important, sometimes decisive, influence on a person's beliefs.  For Marxists, the key thought was that the "standpoint" resulted in distortion of one's knowledge, because it was tainted by the interests associated with one's social position.  In the Marxist version of standpoint epistemology, the working classes did not have any special epistemic access to the actual facts about their situation–to the contrary, their understanding of the actual state of affairs was distorted by the ideology propagated by a different, dominant class, which systematically distorted social reality in its own interests.  Marxists, like Marx, assumed (correctly) that there is an epistemically superior description of social reality that is not tainted by standpoint, and which can serve as a check on the ideological delusions promoted by dominant groups.

By contrast, in recent bourgeois academic philosophy–that is, philosophizing by well-to-do professors who never challenge the prerogatives of the capitalist class, which is basically almost all of current philosophy in the Anglophone world–standpoint epistemology has, ironically, been turned on its head.   Now the social position of the purported "knower"–usually "race" or "gender" or "sexual orientation"–is not taken to be a distorting influence on cognition, but rather an epistemic advantage, one which even demands epistemic deference by others.  We have travelled rather far from Marx.

(I thank Clifford Sosis for a stimulating e-mail exchange on this topic, though the ideas are strictly my own!)