Our Marvelous, Magnificent Brains: How Science is Unraveling the Mysteries of the Mind

The human brain is the most complex organism in the known universe. There are 100 billion neurons inside your head, a number on par with all the stars in the heavens. Furthermore, each neuron may connect to as many ten thousand other neurons. When one ponders the computational power of the brain the results are mind-boggling.

Are our brains smart enough to figure out how they work? For thousands of years the mysteries of consciousness seemed beyond all reckoning. Even the greatest geniuses were stumped. Consciousness must be a divine spark, an immaterial essence, a ghost in the machine. At least that's as far as some of best minds of antiquity could go. Now, however, thanks to revolutionary technologies, such as brain imaging devices, scientists can actually peer into the living human brain in real time as it solves problems, processes information, and imagines the future.

In a sense, each of us has more than one brain. That is, each brain is divided into two hemispheres, a left and a right, which is connected by a tract of nerve fibers called the corpus collosum that allows the hemispheres to communicate with each other. To help patients with epilepsy scientists are sometimes forced to sever this connection. This can result in a rather in rather strange phenomena: the emergence of two distinct centers of consciousness within the same skull. As neuroscientist Stephen Pinker so aptly describes this amazing occurrence, it's "as if the soul could be cleaved in two with a knife."