Your brain is far too complex and mercurial for its behavior to be predicted in any but the broadest outlines or for any but the shortest distances in the future. Faced with the extraordinary dynamical features of a functioning brain, no device constructible in this universe could ever predict your behavior, or your thoughts, with anything more than merely statistical success. ¶ So one need not fear being reduced to a clanking robot or an empty machine. Quite to the contrary, we are now in a position to explain how our vivid sensory experience arises in the sensory cortex of our brains: how the smell of baking bread, the sound of an oboe, the taste of a peach, and the color of a sunrise are embodied in a vast chorus of neural activity. We now have the resources to explain how the motor cortex, the cerebellum, and the spinal cord conduct an orchestra of muscles to perform the cheetah’s dash, the falcon’s strike, or the ballerina’s dying swan. … On this matter of conceptual development there is especial cause for wonder. For the human brain, with a volume of roughly a quart, encompasses a space of conceptual and cognitive possibilities that is larger, by one measure at least, than the entire astronomical universe. It has this striking feature because it exploits the combinatorics of its 100 billion neurons and their 100 trillion synaptic connections with each other.