In 1995 Clark had co-written a paper titled “The Extended Mind,” which opened with a deceptively simple question: “Where does the mind stop and the rest of the world begin?” Clark and his coauthor, philosopher David Chalmers, noted that we have traditionally assumed that the mind is contained within the head—but, they argued, “there is nothing sacred about skull and skin.” Elements of the world outside may effectively act as mental “extensions,” allowing us to think in ways our brains could not manage on their own.
