Agency in the Evolutionary Transition to Multicellularity

This review discusses concepts of how agency, defined here as organism-initiated behavior (both species-characteristic and individually idiosyncratic), was aligned at the cellular and integrated in the multicellular levels during evolution. We consider agency in relation to the autonomy and purposiveness of cells and multicellular organisms. While the agency of cells in extant multicellular forms (and inferred in single-cell antecedents) is assumed in our analysis, we do not speculate on its origins. We attempt to discern the role of agency in the generation of form and function in social bacteria and amoebae, and we speculate on how these phenomena may relate to the emergence of phenotypically complex organisms. For the latter question, we explore the processes leading to morphological and functional enablements in metazoans and how these might change the character of organismal agency during evolution. We also consider how transitions between multicellular agency and unicellular agency (and back again) may characterize and drive the formation of cancers. We relate this problem to the philosophical discourse on dispositional causality and discuss experimental approaches to identifying genuine agency against a background of physically mediated directionality and evolved program-like behaviors of organisms. Lastly, we discuss the possible uses of mathematical representations of incompletely specified dynamical systems in the characterization of autonomy and agency.