Book review: Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness, by Peter Godfrey-Smith.
This book describes some interesting mysteries, but provides little help at solving them.
It provides some pieces of a long-term perspective on the evolution of intelligence.
Cephalopods’ most recent common ancestor with vertebrates lived way back before the Cambrian explosion. Nervous systems back then were primitive enough that minds didn’t need to react to other minds, and predation was a rare accident, not something animals prepared carefully to cause and avoid.
So cephalopod intelligence evolved rather independently from most of the minds we observe. We could learn something about alien minds by understanding them.
Intelligence may even have evolved more than once in cephalopods – nobody seems to know whether octopuses evolved intelligence separately from squids/cuttlefish.
An octopus has a much less centralized mind than vertebrates do. Does an octopus have a concept of self? The book presents evidence that octopuses sometimes seem to think of their arms as parts of their self, yet hints that their concept of self is a good deal weaker than in humans, and maybe the octopus treats its arms as semi-autonomous entities.
Does an octopus have color vision? Not via its photoreceptors the way many vertebrates do. Simple tests of octopuses’ ability to discriminate color also say no.
Yet octopuses clearly change color to camouflage themselves. They also change color in ways that suggest they’re communicating via a visual language. But to whom?
One speculative guess is that the color-producing parts act as color filters, with monochrome photoreceptors in the skin evaluating the color of the incoming light by how much the light is attenuated by the filters. So they “see” color with their skin, but not their eyes.
That would still leave plenty of mystery about what they’re communicating.
The author’s understanding of aging implies that few organisms die of aging in the wild. He sees evidence in Octopuses that conflicts with this prediction, yet that doesn’t alert him to the growing evidence of problems with the standard theories of aging.
He says octopuses are subject to much predation. Why doesn’t this cause them to be scared of humans? He has surprising anecdotes of octopuses treating humans as friends, e.g. grabbing one and leading him on a ten-minute “tour”.
He mentions possible REM sleep in cuttlefish. That would almost certainly have evolved independently from vertebrate REM sleep, which must indicate something important.
I found the book moderately entertaining, but I was underwhelmed by the author’s expertise. The subtitle’s reference to “the Deep Origins of Consciousness” led me to expect more than I got.