Stuart A Newman, Mariana Benítez, Ramray Bhat, Tilmann Glimm, K. Vijay Kumar, Vidyanand Nanjundiah, Daniel J. Nicholson, Sahotra Sarkar

This review explores the concept of agency. Behavior intrinsic to an organism and initiated by it may be taken as evidence of agency, though, as we will discuss, the word has wider ramifications. An organism’s agential behavior has aspects that are both characteristic of its species and idiosyncratic. We ask how agential features exhibited by cells might change concomitantly with the evolutionary transition from unicellularity to multicellularity. Also, we consider agency in relation to the autonomy and purposiveness of cells and multicellular organisms. We assume that multicellular forms and the cells of which they are composed exhibit agency, as did their single-celled ancestors in the past, but we do not speculate on the evolutionary origins of agency. We discuss experimental approaches to distinguish between agency and evolved, program-like behaviors of organisms including directed actions. We attempt to discern attributes of agency in the development of form and function during the life cycles of social bacteria and amoebae and speculate on how similar considerations may apply to phenomena in phenotypically complex organisms. For the latter question, we consider the possibility that as a side-effect of selection for a trait, evolution may lead to the unselected appearance of morphological and functional enablements. In turn, the enablements can change the character of organismal agency during subsequent evolution. We also consider how back-and-forth transitions between multicellular agency and unicellular agency may be useful in understanding cancer. We relate the notion of agency to ideas of dispositional causality. Lastly, we discuss mathematical representations of incompletely specified dynamical systems and how they may be used to characterize autonomy and agency.