The physical brain, of both humans and animals, has begun to give up its secrets. Those secrets have been locked away in a bony vault, encrypted in a microscopic matrix of 100 billion neurons and 100 trillion synaptic connections, for the entire history of our philosophical musings, with no more influence on the content of those musings than the influence exerted by the equally hidden secrets of the kidney, or the secrets of the pancreas. The winding path of our philosophical theorizing has been steered by other factors entirely. Those factors have been many and various, even glorious, and they have been precious for existing at all. But they have not included even the feeblest conception of how the biological brain embodies information about the world, or of how it processes that information so as to steer its biological body through a complex physical and social environment. In these dimensions, we have been flying blind for at least three millennia.

But our blinders here have begun to be lifted, and our ignorance has begun to recede. A new generation of techniques and machines of observation has given us eyes to see into the encrypted details of neuronal activity. A new generation of scientists has given us a self-critical community of determined empirical researchers. And a new generation of theories has given us at least an opening grip on how the brain's massive but microscopic matrix might perform the breathtaking feats of real-time cognition that so compel our philosophical attention.