Book review: “The Four Realms of Existence. A New Theory of Being Human” by Joseph LeDoux.

In The Four Realms of Existence: A New Theory of Being Human, Joseph LeDoux (2023) argues for a conceptualization of being human in terms of four hierarchically integrated realms of existence: biological, neurobiological, cognitive, and conscious. Although LeDoux’s perspective is thought-provoking, it also raises several questions. One question is how to differentiate the conscious realm from the cogni-tive realm. Another question is where feelings and non-verbal expressions fit into LeDoux’s picture. An overarching question is also: why four realms of existence?