Pluralism, Entwinement, and the Levels of Selection

This paper distinguishes and critiques several forms of pluralism about the levels of selection, and introduces a novel way of thinking about the biological properties and processes typically conceptualized in terms of distinct levels. In particular, "levels" should be thought of as being entwined or fused. Since the pluralism discussed is held by divergent theorists, the argument has implications for many positions in the debate over the units of selection. And since the key points on which the paper turns apply beyond this specific issue, the paper may prove of general interest in thinking about the metaphysics of science.