Out of necessity, Caro found his way to a mode of thinking and working that would not have been possible had he tried to keep his voluminous material entirely in his head. “When thought overwhelms the mind, the mind uses the world,” psychologist Barbara Tversky has observed. Once we recognize this possibility, we can deliberately shape the material worlds in which we learn and work to facilitate mental extension—to enhance “the cognitive congeniality of a space,” in the words of David Kirsh, a professor at the University of California, San Diego.
