The Invention of Consciousness

By Nicholas Humphrey

The story of a quest to uncover the evolutionary history of consciousness from a leading theoretical psychologist.





The story of a quest to uncover the evolutionary history of consciousness from a leading theoretical psychologist.

We feel, therefore we are. Conscious sensations ground our sense of self. They are crucial to our idea of ourselves as psychic beings: present, existent, and mattering. But is it only humans who feel this way? Do other animals? Will future machines? Weaving together intellectual adventure and cutting-edge science, Nicholas Humphrey describes his fifty-year quest for answers: from his discovery of blindsight in monkeys and his pioneering work on social intelligence to breakthroughs in the philosophy of mind.

The goal is to solve the hard problem: to explain the wondrous, eerie fact of “phenomenal consciousness”—the redness of a poppy, the sweetness of honey, the pain of a bee sting. What does this magical dimension of experience amount to? What is it for? And why has it evolved? Humphrey presents here in full a new, plausible solution that phenomenal consciousness, far from being primitive, is a relatively late and sophisticated evolutionary development. The implications for the existence of sentience in nonhuman animals are startling and provocative.


$24.95 T ISBN: 9780262047944 256 pp. | 6 in x 9 in 19 b&w illus.

For sale in North America only.


  • "It takes a special kind of person to write illuminatingly about consciousness—a person who is not only steeped in cognitive science, biology, and philosophy, but also has a fertile imagination, an openness to new ideas, and a sensitivity to the richness and variety of experience in humans and other animals. Nicholas Humphrey is such a person, and in his new book he cements his claim to be one of the most insightful writers on this notoriously difficult topic. Sentience is a beautifully written book, full of engaging vignettes, original ideas, and intriguing suggestions. It will fascinate general readers and inspire academic researchers."

    Keith Frankish

    philosopher of mind; author of Illusionism as a Theory of Consciousness

  • "For half a century, Nick Humphrey has been a hugely influential figure across the fields of experimental psychology, neuroscience, and philosophy, and, for my money, is the most inventive psychological thinker of his generation. Taking a long view of his entire scientific career and peppered with brilliant anecdotes, Sentience crystallizes Humphrey's latest thinking on the evolution of consciousness. There are many dazzling insights on offer, but, for me, the most eye-catching development is the formulation of a framework for diagnostic sentience-testing—in other words, for determining which other animal species are sentient or even in possession of a sense of self. How staggeringly bold! Imagine what a shock wave such a test would generate—scientifically and philosophically, of course, but also out into the political sphere."

    Paul Broks

    author of Into the Silent Land: Travels in Neuropsychology and The Darker the Night, the Brighter the Stars: A Neuropsychologist's Odyssey Through Consciousness