Computationalism has been the pre-eminent framework for models of mind, since the cognitive revolution. However,the plethora of apparently incommensurate approaches seems to undermine hope for a common computational foundation.Category theory provides a mathematically rigorous foundation for computation that includes recursion and corecursion. Weshow that corecursion unifies various cognitive behaviours for comparison and contrast in a principled and novel way. Forinstance, Chomsky’s merge function is a universal morphism, which has a dual, called comerge. One implication of this workis that corecursion appears to be the rule rather than the (human) exception in contrast to Chomsky’s view of recursion.
