Conscious mental states, like internal states, are best understood as states with chracteristic functional roles; similarly a mousetrap is really a mousetrap because of the function it serves, not because of any particular material, shape, or parts it might have.

Postulates Of Functionalism

1) A mental state is a functional state.

2) A functional state consists of causal imputs, causal outputs, and causal relationships to the other functional states.

3) A functional state is purely formal, abstract, and relational (see sidebar, "Formal systems: an overview" on Map 7).

4) So, functional states can be realised in multiple physical media. This is called multiple realisability (see the "Is the brain a computer?" arguments on Map 1).

5) So, we can study the mind without studying the brain.

Proponents on these maps include: David Chalmers, Jerry Fodor, John McCarthy, Brian McLaughlin, Zenon Pylyshyn and Hilary Putnam.

Notes:

• This is a general description of functionalism many more specific versions have been articulated in the context of psychology, philosophy of mind, any eye, and connectionism.

• Arguments about functionalism pervade Maps 3 and 4, and are prominent on Map 5.