Functionalism and Vehicle Externalism
Clark and Chalmers’s active externalism is commonly thought to be a form of vehicle externalism. Thought extends across external vehicles of thought, such as Scrabble trays and letters. One way to think about vehicle externalism is as extended functionalism. Clark and Chalmers note that what drives my thinking when I play Scrabble is how letters are arranged. At each moment in time, the coupled letter system is in a state that acts causally to produce the next state. This is basically an extended functionalist view. While traditional functionalists understand vehicles of thought as being within the head, vehicle externalists argue that they can also be found externally. Causal relations between mental states in the head, as well as external vehicles of cognition (e.g., Scrabble letters on a tray), drive thought. In the view of vehicle externalism, the mind extends to form coupled causal vehicle systems with the world.
Contingency and Coupling
Clark and Chalmers understand that we might be unwilling to accept their view of the mind as extended, because vehicle couplings with the world could seem unreliable. But we could imagine artificial vehicle couplings inside our heads that would be dependable. Imagine that someone gets a short-term memory module plugged into the brain. If such a chip could be constructed, couldn’t it function in a dependable way? But we need not imagine such futuristic scenarios. In their view, we should think of vehicle couplings with everyday objects, such as books and pocket calculators, as being reliable. Someone who carries an agenda around and consults it routinely has reliable cognitive couplings with it.
But are not calculators, agendas, and notebooks simply tools? Our ways of thinking might depend on them, but is not thinking something we do with our brain? Is not our cognitive machinery all about brain states? Saying these things begs the question in Clark and Chalmers’s view. Their thesis is that the mental extends beyond the brain. They are trying to debunk what they think are false intuitions about the mental.