Ultimately we will only understand biological agency when we have developed a theory of the organization of biological processes, and science is still a long way from attaining that goal. It may be possible nonetheless to develop a list of necessary conditions for the emergence of minimal biological agency. The authors offer a model of molecular autonomous agents which meets the five minimal physical conditions that are necessary (and, we believe, conjointly sufficient) for applying agential language in biology: autocatalytic reproduction; (...) work cycles; boundaries for reproducing individuals; self-propagating work and constraint construction; and choice and action that have evolved to respond to food or poison. When combined with the arguments from preadaptation and multiple realizability, the existence of these agents is sufficient to establish ontological emergence as against what one might call Weinbergian reductionism. Minimal biological agents are emphatically not conscious agents, and accepting their existence does not commit one to any robust theory of human agency. Nor is there anything mystical, dualistic, or non-empirical about the emergence of agency in the biosphere. Hence the emergence of molecular autonomous agents, and indeed ontological emergence in general, is not a negation of or limitation on careful biological study but simply one of its implications. (shrink)