Methodology, Epistemology and Conventions: Popper's Bad Start

Popper's conception of methodology and its relationship to epistemology is examined, and found wanting. Popper argues that positivist criteria of demarcation fail because they are attempts to discover a difference in the natures of empirical science and metaphysics. His alternative to naturalism is that a plausible criterion of demarcation is a proposal for an agreement, or convention. But this conventionalism about methodology is misplaced. Methodological rules are conventions, but which methodological rules are followed by scientists it is not itself a matter of convention. This casts doubt upon the status of Popper's famous criterion of demarcation.