Biological possibility: a mechanistic account

Abstract Current projects in synthetic biology, universal biology, and the origin-of-life study have posed a pressing issue regarding the nature of biological possibility. This essay proposes a novel account of biological possibility, which highlights the role of mechanism: X is biologically possible just in case there is a possible life-defining or life-participating mechanism that actualizes X, and such mechanisms determine the features that individuate X. This mechanistic account captures a broad scope of biological possibilities while affording sufficient constraints in delivering them, thus being superior to three previous accounts (the “Library of Mendel,” combinatorial, and law-based accounts).