Philosophers Refine Definitions Of Biological Life

This essay surveys historical and contemporary approaches to defining life, outlining theoretical, operational, nominal, ostensive, and stipulative definitions and modern prototype, exemplar, and theory-concept accounts. It critiques theoretical definitions as too rigid and operational definitions as practically useful but philosophically shallow, citing Plato, Aristotle and modern authors. The discussion highlights implications for marginal cases like viruses, prions, and hypothetical non-carbon life.