TECH PROPHECY AND THE UNDERAPPRECIATED CAUSAL POWER OF IDEAS Steven Pinker Steven Pinker, a Johnstone Family Professor in the Department of Psychology at Harvard University, is an experimental psychologist who conducts research in visual cognition, psycholinguistics, and social relations. He is the author of eleven books, including The Blank Slate, The Better Angels of Our Nature, and, most recently, Enlightenment Now: The Case for Reason, Science, Humanism, and Progress. Artificial intelligence is an existence proof of one of the great ideas in human history: that the abstract realm of knowledge, reason, and purpose does not consist of an élan vital or immaterial soul or miraculous powers of neural tissue. Rather, it can be linked to the physical realm of animals and machines via the concepts of information, computation, and control. Knowledge can be explained as patterns in matter or energy that stand in systematic relations with states of the world, with mathematical and logical truths, and with one another. Reasoning can be explained as transformations of that knowledge by physical operations that are designed to preserve those relations. Purpose can be explained as the control of operations to effect changes in the world, guided by discrepancies between its current state and a goal state. Naturally evolved brains are just the most familiar systems that achieve intelligence through information, computation, and control. Humanly designed systems that achieve intelligence vindicate the notion that information processing is sufficient to explain it—the notion that the late Jerry Fodor dubbed the computational theory of mind. The touchstone for this volume, Norbert Wiener’s The Human Use of Human Beings, celebrated this intellectual accomplishment, of which Wiener himself was a foundational contributor. A potted history of the mid-20th-century revolution that gave the world the computational theory of mind might credit Claude Shannon and Warren Weaver for explaini