" Though it accounts for only 2 percent of the body’s mass, it uses up a fifth of all the oxygen we breathe, and it’s where a quarter of all our glucose gets burned. The brain is the most energetically expensive piece of equipment in our body, and has been ruthlessly honed by natural selection to be efficient at the tasks for which it evolved. One might say that the whole point of our nervous system, from the sensory organs that feed information to the glob of neurons that interprets it, is to develop a sense of what is happening in the present and what will happen in the future, so that we can respond in the best possible way. Strip away the emotions, the philosophizing, the neuroses, and the dreams, and our brains, in the most reductive sense, are fundamentally prediction and planning machines. "
― Joshua Foer , Moonwalking with Einstein: The Art and Science of Remembering Everything