Hume's fork

"If the positivist model of scientific knowledge is false, does it mean that the only cure is a thoroughgoing relativism? For the record, positivism is not the only game in town in the natural or social sciences. It is not the only conception of science. Marx's critique of bourgeois philosophy, political economy, and utopian socialism is the first stage leading to the affirmation of a dialectical materialist conception of science. Marx's rejection of empiricism, as the epistemological basis for science, is fundamentally a discarding of the empiricist premise—that science is exclusively descriptive and devoid of prescriptive tasks. The concepts of exploitation, class struggle, and the theory of reification, for example, possess both a descriptive and normative (critical) aspect for Marx. After all, Marx made it very plain: Capital is A Critique of Political Economy. Hence, Hume's fork has no place at a Marxist dinner table."

"All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, relations of ideas, and matters of fact. Of the first kind are the sciences of Geometry, Algebra, and Arithmetic ... [which are] discoverable by the mere operation of thought ... Matters of fact, which are the second object of human reason, are not ascertained in the same manner; nor is our evidence of their truth, however great, of a like nature with the foregoing."