Four Realms of Existence : A New Theory of Being Human

A Seminary Co-op Notable Book

“A big picture perspective on the mind, decision-making, and consciousness…Provocative and stimulating.” ―Philosophical Psychology

“LeDoux’s aim is to provide a new theory of being human by dividing our evolutionary past into four realms: biological at the bottom, then neurobiological, cognitive and conscious…Along the way are excellent accounts of the evolution of brain structures and cognitive abilities.” ―New Scientist

“A rigorously scientific yet eminently readable exploration of what it means to be human.” ―Publishers Weekly

Modern science has largely dispensed with mind-body dualism, yet people still tend to imagine their minds as separate from their physical being. Even researchers persistently presume a “self” somehow distinct from the rest of the organism.

Arguing that the self is a barrier to understanding, leading neuroscientist Joseph LeDoux offers a new framework based on four realms of existence: bodily, neural, cognitive, and conscious. Every living thing, whether bacterium or plant or animal, has a body. Animals alone then supplement such biological existence with a nervous system, which enables quick and precise control of the organism. Certain animals can also think and plan, and thus exist cognitively. Finally, some of the cognitive organisms have inner experiences of and thoughts about the world―the hallmarks of the conscious realm.

These four realms cooperate continuously to create the experience of a being with a past, present, and future. The result, LeDoux shows, is not a self but an “ensemble of being” that subsumes humans’ entire existence, both as individuals and as a species.