Active and Passive Externalism
According to Clark and Chalmers, cognition extends beyond our skulls—into the world and across tools. Moreover, our actions drive further actions, and Clark and Chalmers ask us to think of action as part of thought. This is a different take on externalism from the content forms of externalism we have considered. Those forms Clark and Chalmers term passive in contrast to their active form.
Imagine playing Scrabble with letters in front of you. You shift them around to make a new word. Clark and Chalmers argue that you form a coupled system with the letters and the tray. Rearranging letters is part of a cognitive action loop that constitutes thinking. But what would an explanation of Scrabble playing look like according to the account of passive externalism?
It is unclear how we could account for the rearrangement with passive external- ism, because it deals with representational contents and not with the activity of thinking as it spans across internal and external vehicles of thought.