Maturana's equation of cognition with effective action in a domain of existence — the biological thesis that knowledge is not representation but the organism's capacity to maintain its autopoiesis through engagement with its world.
A bacterium moving up a chemical gradient toward glucose is not computing an optimal trajectory or building an internal model of sugar distribution. It is generating directed movement through molecular mechanisms that produce effective action — action that maintains the organism's continued self-production. In Maturana's framework, that effective action is cognition. Not a metaphor for cognition, not a primitive version of it, but cognition. Knowing is the capacity for effective action; doing is the knowing. The formulation dismantles the representational model of mind that has dominated Western philosophy since Descartes. The organism does not need to represent the world accurately; it needs only to generate internal states that, coupled with its motor repertoire, produce behaviors that maintain viability. The frog does not need to know the dark moving spot is a fly — it needs only to generate a state that triggers the tongue at the right moment.