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The idea of the brain as an information processor—a machine manipulating blips of energyaccording to fathomable rules—has come todominate neuroscience. However, one enemy of the brain-as-computer metaphor is John R. Searle,a philosopher who argues that since computerssimply follow algorithms, they cannot deal with important aspects of human thought such asmeaning and content. Computers are syntactic, rather than semantic, creatures. People, on the other hand, understand meaning because they have something Searle obscurely calls the causal powers of the brain.Yet how would a brain work if not by reducing what it learns about the world to information—some kind of code that can be transmitted from neuron to neuron? What else could meaning and content be? If the code can be cracked, a computer should be able to simulate it, at least in principle. But even if a computer could simulate the workingsof the mind, Searle would claim that the machinewould not really be thinking; it would just be actingas if it were. His argument proceeds thus: if acomputer were used to simulate a stomach, with the stomach’s churnings faithfully reproduced on a video screen, the machine would not be digestingreal food. It would just be blindly manipulating the symbols that generate the visual display.Suppose, though, that a stomach were simulated using plastic tubes, a motor to do the churning, a supply of digestive juices, and a timing mechanism.If food went in one end of the device, what came out the other end would surely be digested food. Brains,unlike stomachs, are information processors, and if one information processor were made to simulate another information processor, it is hard to see how one and not the other could be said to think. imulated thoughts and real thoughts are made ofthe same element: information. The representations of the world that humans carry around in their heads are already simulations. To accept Searle’s argument,one would have to deny the most fundamental notionin psychology and neuroscience: that brains work by processing information.