Functionalism in philosophy of mind: Methodology or ontology?

The article investigates two functionalist accounts of the mind developed in the middle of the 20th century: analytical functionalism of David Armstrong and David Lewis and computational functionalism of Hilary Putnam. The aim is to show that the two accounts are identical from the methodological point of view, but their proponents give different ontological interpretations to the methodological base of their theories. While they agree that the concept of 'functional state' is different from the concept of 'physical state', they nevertheless disagree on whether 'functional state' should be taken to designate a distinct ontological kind of states or it should be taken as expressing a different way of identifying the same physical states in the actual world. This disagreement could be taken to mark the beginning of the controversy characteristic of contemporary philosophy of mind regarding the question whether the ontology of properties should be reconstructed on the intensive or extensive basis.