Sentience

The story of a quest to uncover the evolutionary history of consciousness from one of the world's leading theoretical psychologists.

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 in Sentience his 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 his new solution. He proposes 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.Prologue vii
1. Sentience and consciousness 1
2. Foothills 13
3. The touch of light 16
4. Blythe spirits 21
5. What the frog's eye tells the monkey's brain 32
6. Blindsight 40
7. Sight unseen 50
8. Red sky at night 54
9. Nature's psychologists 67
10. On the track of sensations 77
11. Evolving sentience 101
12. The road taken 105
13. The phenomenal self 114
14. Theoretical misprisions 125
15. Coming to be: Sentience and body sense 130
16. Sentience all the way down? 134
17. Mapping the landscape 145
18. Getting warmer 148
19. Testing, testing 153
20. Qualiaphilia 158
21. The self in action 175
22. Taking stock 202
23. Machina ex deo 207
24. Ethical imperatives 214
Acknowledgments 219
References and notes 221
Index 239Included in Lit Hub’s Most Anticipated Books of 2023 

"The history of science has alwyas relied on hard lines and clear categories, and for a long time one of the hardest of those lines was that between sentience and non-sentience. But as theoretical psychologist Nicholas Humphrey explores in Sentience, that line may not be as clear as initially thought, as discoveries in machine-learning, neurobiology, and animal consciousness raise more questions than they answer."
— Lit Hub

"Wonderfully approachable . . . with a writing style somewhere between a deep conversation and a thought process. I particularly loved Humphrey's description of his heading off to Elba to investigate the paranormal claims of the eccentric Hugh Sartorius Whitaker and his experiences with Dian Fossey (not always pleasant) when visiting to study the 'natural psychologist' ability of gorillas. . . .  Reading this book was a real pleasure."
— Brian Clegg, Popular Science (UK)
 
“A stimulating exercise in experiment and speculation. . . [a] fascinating premise. . . . Complex and sometimes counterintuitive concepts rendered with admirable skill.”
— Kirkus Reviews

"Nicholas Humphrey’s Beautiful Theory of Mind. . . . In his new book, Sentience, a neuropsychologist argues that consciousness evolved to make us feel that life is worth living."
—The New Yorker

"Sentience is full of provocative ideas, as well as lively anecdotes from decades of pondering these issues. Humphrey’s thesis offers a great deal to think about....[H]is book earns its place...and is a valiant reminder of how much there still is to understand."
— New Scientist

“bold, brilliant, honest … [Humphreys’] directness and philosophical sophistication are unusual in the crowded and noisy neuroscientific marketplace … [An] important contribution to the debate. All future writers on consciousness will need to take Humphrey’s speculations seriously. It is no less significant because it’s written breezily and accessibly. I know of no better survey of the big questions in discussions about consciousness.”
— The Fortean Times




“A compelling treatise on the evolution of consciousness from one of our finest psychologists. His excellent book will challenge you to think about nature’s deepest and most personal mystery in a new and thoroughly enlightening way.”
—Anil Seth, author of Being You
 
“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
 
“Nick Humphrey has been a hugely influential figure across the fields of experimental psychology, neuroscience, and philosophy for half a century, 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


"Nobody has thought more deeply, originally or poetically about animal sentience and the notion of consciousness. In this bold and persuasive book he lays out how he came to his conclusions in a lifetime of studying animal and human minds."
—Matt Ridley, author of The Red Queen and other books

"Nicholas Humphrey is a psychologist who has always thought outside the box. In this bold book he goes back to basics, philosophical and biological. It's a provocative and fascinating read, brought to life by the account of his own pioneering work on blindsight."
—Marian Stamp Dawkins, author of Why Animals Matter
Nicholas Humphrey, Emeritus Professor of Psychology at the London School of Economics, is a theoretical psychologist based in Cambridge, who studies the evolution of intelligence and consciousness. He was the first to demonstrate the existence of “blindsight” in monkeys. He has also studied mountain gorillas with Dian Fossey in Rwanda, proposed the celebrated theory of the “social function of intellect,” and investigated the evolutionary background of religion, art, healing, death-awareness and suicide. His honors include the Martin Luther King Memorial Prize, the Pufendorf Medal, and the International Mind and Brain Prize. His most recent books are Seeing Red and Soul Dust.