Descartes' Error: Emotion, Reason, and the Human Brain is a book by neurologist Antonio R. Damasio, in which the author presents the argument that emotion and reason are not separate but, in fact, are quite dependent upon one another.
Damasio argues that the body is the genesis of thought. The philosopher René Descartes developed a method of reasoning based on the indisputable observation that if we think, we must exist. However, Damasio examines the physiological processes that contribute to the functioning of the mind and therefore proposes the idea that thinking is inherent to a body in which no spirit exists. The fundamental difference in argument situates itself in that thought is a physiological function, based on anatomy making the statement "I think, therefore I am" a tautology. It essentially becomes "I am, therefore I am" when Damasio's principle of the body-mind rather than dualism is applied. This presents the reason why the work is titled Descartes' Error.
Damasio explores in depth the famous case of Phineas Gage. While Gage's intelligence remained intact after his brain was damaged in an 1848 accident, Damasio believes that Gage's ability to reason and make rational decisions became severely handicapped because his emotions could no longer be engaged in the process. Damasio uses this and other brain-damage cases to develop his thesis on emotion and its relationship to human activity. He argues that rationality stems from our emotions, and that our emotions stem from our bodily senses. The state of the mind, or feeling, is merely a reflection of the state of the body, and feeling is an indispensable ingredient of rational thought.
- Descartes' Error: Emotion, Reason, and the Human Brain, Putnam Publishing, 1994, hardcover: ISBN 0-399-13894-3