Walsh, D. M.

Jacques Monod’s Chance and Necessity poses a paradox for modern biology: Organisms both must be and cannot be purposive systems. To resolve the paradox we must explain purpose by appeals to invariance or invariance by appeal to purpose. The methodology of modern science, however, allows no unreduced appeals to purpose. Monod traces the modern synthesis commitment to ineluctable chance back to its animadversion to teleology. He credits the pre-Socratic Atomist philosopher Democritus with holding that everything in the world is the fruit of chance and necessity. It is becoming increasingly obvious that their purposiveness is pivotal to the dynamics of evolution. This chapter outlines a ‘neo-Aristotelian’ alternative to the neo-Democritean commitments of modern synthesis biology, one that accords the purposiveness of organisms a central explanatory role in evolution.