Autopoiesis with or without cognition: defining life at its edge.

This paper examines two questions related to autopoiesis as a theory for minimal life: (i) the relation between autopoiesis and cognition; and (ii) the question as to whether autopoiesis is the necessary and sufficient condition for life. First, we consider the concept of cognition in the spirit of Maturana and Varela: in contradistinction to the representationalistic point of view, cognition is construed as interaction between and mutual definition of a living unit and its environment. The most direct form of cognition for a cell is thus metabolism itself, which necessarily implies exchange with the environment and therefore a simultaneous coming to being for the organism and for the environment. A second level of cognition is recognized in the adaptation of the living unit to new foreign molecules, by way of a change in its metabolic pattern. We draw here an analogy with the ideas developed by Piaget, who recognizes in cognition the two distinct steps of assimilation and accommodation. While assimilation is the equivalent of uptake and exchange of usual metabolites, accommodation corresponds to biological adaptation, which in turn is the basis for evolution. By comparing a micro-organism with a vesicle that uptakes a precursor for its own self-reproduction, we arrive at the conclusion that (a) the very lowest level of cognition is the condition for life, and (b) the lowest level of cognition does not reduce to the lowest level of autopoiesis. As a consequence, autopoiesis alone is only a necessary, but not sufficient, condition for life. The broader consequences of this analysis of cognition for minimal living systems are considered.