Sizing up Consciousness

Sizing up Consciousness explores, at an introductory level, the potential practical, clinical, and ethical implications of a general principle about the nature of consciousness. Using information integration theory (IIT) as a guiding principle, the book takes the reader along a scientific trajectory to face fundamental questions about the relationships between matter and experience. What is so special about a piece of flesh that can host a subject who sees light or experiences darkness? Why is the brain associated with a capacity for consciousness, but not the liver or the heart, as previous cultures believed? Why the thalamocortical system, but not other complicated neural structures? Why does consciousness fade during deep sleep, while cortical neurons remain active? Why does it recover, vivid, and intense, when the brain is disconnected from the external world during a dream? Can unresponsive patients with a functional island of cortex surrounded by widespread damage be conscious? Is a parrot that talks, or an octopus that learns and plays conscious? Can computers be conscious? Could a system behave like us and yet be devoid of consciousness—a zombie? The authors take on these basic questions by translating theoretical principles into anatomical observations, novel empirical measurements—such as an index of brain complexity that can be applied at the bedside of brain-injured patients—and thought experiments. The aim of the book is to describe, in an accessible way, a preliminary attempt to identify a general rule to size up the capacity for consciousness within the human skull and beyond.