Two neuroscientists reveal why consciousness exists and how it works by examining eighteen increasingly intelligent minds, from microbes to humankind—and beyond.Why do you exist? How did atoms and molecules transform into sentient creatures that experience longing, regret, compassion, and even marvel at their own existence? What does it truly mean to have a mind—to think? Science has offered few answers to these existential questions until now.Journey of the Mind is the first book to offer a unified account of the mind that explains how consciousness, language, self-awareness, and civilization arose incrementally out of chaos. The journey begins three billion years ago with the emergence of the universe's simplest possible mind. From there, the book explores the nanoscopic archaeon, whose thinking machinery consists of a handful of molecules, then advances through amoebas, worms, frogs, birds, monkeys, and humans, explaining what...