The Emperor's New Mind attacks the claims of artificial intelligence using the physics of computing: Penrose notes that the present home of computing lies more in the tangible world of classical mechanics than in the imponderable realm of quantum mechanics. The modern computer is a deterministic system that for the most part simply executes algorithms. Penrose shows that, by reconfiguring the boundaries of a billiard table, one might make a computer in which the billiard balls act as message carriers and their interactions act as logical decisions.