The big questions of our lives bring fierce debates. Right and wrong. Freedom and responsibility. Women and men. Democracy and justice. Ambition and fulfilment. Where do answers lie in a mind that produces the many sides and needs of humanity?In The Animal and the Thinker, pioneering neuroscientist John Duncan lays out the principles, strengths and weaknesses of two sides of ourselves. One side follows the principles of instinctive animal behaviour. It is elaborate, sophisticated, conflicted yet essential - without it, our life would have no meaning. On the other side is our rational brain. It generates an infinite world of new ideas, but often, its need for focus generates sterile social beliefs and destructive culture wars. Our rational side is brilliant, but often, it is wrong. For thousands of years, writers, thinkers and philosophers have seen human life as a war between Dr Jekyll and Mr Hyde. Duncan shows that there is no war. To bring humanity and reality to the great, conflicted questions of our lives, we need the dance between these two essential sides of ourselves.