Might we humans be the only species on this planet to be truly conscious? Might lobsters and lions, beetles and bats be unconscious automata, responding to their worlds with no hint of conscious experience? Aristotle thought so, claiming that humans have rational souls but that other animals have only the instincts needed to survive. In medieval Christianity the “great chain of being” placed humans on a level above soulless animals and below only God and the angels. And in the 17th century French philosopher René Descartes argued that other animals have only reflex behaviors. Yet the more biology we learn, the more obvious it is that we share not only anatomy, physiology and genetics with other animals but also systems of vision, hearing, memory and emotional expression. Could it really be that we alone have an extra special something—this marvelous inner world of subjective experience?