We feel therefore we are. Conscious sensations ground our sense of self. They are essential to our idea of ourselves as psychic beings: present, existent, and mattering. But is it only humans who feel this way? Do other animals? Will future machines? To answer these questions we need a scientific understanding of consciousness: what it is and why it has evolved. Nicholas Humphrey has been researching these issues for fifty years. In this extraordinary book, weaving together intellectual adventure, cutting-edge science, and his own breakthrough experiences, he tells the story of his quest to uncover the evolutionary history of consciousness: from his discovery of blindsight after brain damage in monkeys, to hanging out with mountain gorillas in Rwanda, to becoming a leading philosopher of mind. Out of this, he has come up with an explanation of conscious feeling - ''phenomenal consciousness'' - that he presents here in full for the first time. Building on this theory of how phenomenal c