Other Minds by Peter Godfrey-Smith was chosen as 2022’s last read in a bookclub I’m part of. The book had this broad subtitle of The Octopus, The Sea and The Deep Origins of Consciousness and the octopus in there got me interested to read it.
We begin with evolution and the tree of life with single-celled organisms much like bacteria. To register their surrounding conditions they start sensing their environments and in the grand run of evolution that leads to signaling with other organisms, then to multi-cellular organisms with organs to sense (like eyes for light). Peter is interested in cephalopods, a group of marine invertebrates that includes octopuses, cuttlefish and squid. Searching for the common ancestor of humans and octopuses in the tree of life leads to Ediacaran organisms like Kimberella. Going from the Kimberella mollusc, evolution leads them to modern cephalopods by losing their shell, swimming in water, growing arms to grab food or fight and evade capture using camouflage and ink.
The author chose cephalopods because they have the most complex nervous systems outside of land vertebrates. The unique thing about their systems is that the nervous systems in their arms are complex and can act autonomously from their brain. A good analogy is between a conductor (brain) and his musicians (arms).
What is the inner mental model of the world for an organism like this? How can cephalopods change their colors? How can those colors match their backgrounds when cephalopods have no eyes on the back and they are color-blind? We learn details of their skin which has layers of color cells, filter cells and reflecting cells and recent discoveries on how they can change colors.
The final chapters get more philosophical. They look at how self is a combination of images and feelings and how humans are unique in having an inner monologue. Do cephalopods have higher order thought? And why does such a highly intelligent animal have a short lifespan of 1-2 years? We look at possible evolutionary and reproductory reasons for this.
The book is essentially a loosely connected set of musings by the author based around his many experiences with octopuses on his dives in Australia and research results on octopuses. I found it interesting to learn about evolution, tree of life, the intelligence and social behavior of octopuses and how researchers do their (often gruesome) experiments to figure out these beings. I love reading about fossils and evolution and this is familiar territory for me covered earlier in Your Inner Fish. The book lags whenever the authors waxs philosophically (which is a lot), gets into vague research details or when there is no clear direction in the writing. And despite the subtitle, it never quite gets to the consciousness part of our life. This was a decent read and I look forward to more books about the fascinating beings like the octopus with which we share this planet.