Oxford biologist John Parrington proposes a radical new theory of human consciousness, arguing that a qualitative leap in consciousness occurred during human evolution as language and tool use transformed our brains. Rejecting outdated views of the brain as a hard-wired circuit diagram, he draws on the latest insights from neuroscience to show that meaning is created within our heads through a dynamic interaction of oscillating brain waves. This new model of consciousness not only provides a material basis of our innermost thoughts but also explains why the mind can sometimes go wrong, causing deep mental distress.