- Bringing these ideas into the field of animal behaviour, I’ve looked at a range of diagnostic criteria that might apply. Does the animal:
- Have a robust sense of self, centred on sensations?
- Engage in self-pleasuring activities – be it listening to music or masturbation?
- Have notions of ‘I’ and ‘you’?
- Carry their sense of their own identity forward?
- Attribute selfhood to others?
- Lend out their minds so as to understand others’ feelings?
- Broadly, these tests confirm my hunch that it’s only mammals and birds who make the cut. Chimpanzees, dogs, parrots we can be sure of. Lobsters, lizards, frogs we can rule out.
- Octopuses? They are everybody’s favourite candidate for an outlying species that is sentient. But the behavioural evidence belies this. On the face of it, octopuses don’t find pleasure in sensation-seeking for sensation’s sake; they don’t have a strong sense of themselves as individuals; they don’t attribute selfhood to others; nor do they care.
- What about man-made machines? There are, of course, already machines in existence that see and hear and smell at their own level. But, as with lobsters and frogs, it’s presumably blind-seeing, blind-hearing, blind-smelling. Given the life-tasks that nonsentient animals and machines have been designed to accomplish, we can assume that phenomenal blindness leaves them none the worse off.
- Nevertheless, let’s suppose that, not so far in the future, human engineers were to want to build robots to undertake a task where sentience and selfhood really might play a role: namely, to survive as significant individuals in a world of other phenomenal selves. Then I can imagine that one day the engineers could in fact take a leaf from Nature’s book and, by duplicating the specialised brain circuits responsible for phenomenal consciousness in humans, build sentience into a machine.
- Nicholas Humphrey is emeritus professor of psychology at the London School of Economics. He is the author of many books on the evolution of human intelligence and consciousness, the latest being Sentience: The Invention of Consciousness (UK 2022; US 2023). He lives in Cambridge, UK.
- This is a plug for the author’s latest book: "Humphrey (Nicholas) - Sentience: The Invention of Consciousness". Any serious discussion will have to await my reading this book.
- The author’s theory looks very interesting, though it sounds a little like ‘blinding with science’ in this short paper.
- I’m ‘happy’ with his conclusions. It seems sensible – and not as radical as the book’s blurb suggests – to restrict phenomenal consciousness to warm-blooded animals. But this doesn’t mean the theory is correct. I’m not sure about octopuses!
- The author (or maybe his editor) sites several other Aeon papers:-
→ "Frankish (Keith) - The Consciousness Illusion",
→ "Pigliucci (Massimo) - Consciousness is real",
→ "Hanlon (Michael) - The mental block",
→ "Seth (Anil Kumar) - The real problem", and
- Also, one of his own:-
→ "Humphrey (Nicholas) - The society of selves".
- There are some useful comments, which I've preserved in PDF form lest they disappear.
- One commentator refused to read further than the introductory account of the 'blind-sighting' of the monkey which Humphrey recounts without any hint that there might be a moral dilemma in (ab-)using an intelligent and sentient being in this way. While I sympathise, I can't see the point in ignoring the results of (by most people's sensibilities today, even if not those of Humphreys) immoral research. Otherwise, animals - and sometimes human animals - have suffered in vain.
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