The Four Realms of Existence: A New Theory of Being Human

Neuroscientist LeDoux (The Deep History of Ourselves) presents a rigorously scientific yet eminently readable exploration of what it means to be human. Writing that “we are hierarchically organized biological units that, for the most part, function as an integrated system,” LeDoux divides human existence into four different “realms”: biological, neurobiological, cognitive, and conscious “ways of being,” each of which requires and presupposes the previous one. These four realms intermingle, he explains, forming an “ensemble of being” that “varies dynamically from moment to moment... in accordance with the activities with which each realm is occupied,” including “pain and pleasure, hunger and thirst, disgust and lust, love and hate, compassion and hope, despair and ecstasy.” Drawing on cognitive and evolutionary psychology, philosophy, biological science, and more, the author delves into complex notions of personality and the self, the construction of internal narratives, and memory, elegantly making the case for the emergent properties of the mind without recourse to an undetectable soul or reducing the complexity of human existence to merely physical factors. The result is a finely wrought, thought-provoking feast for the mind. (Oct.)