This fascinating book is subtitled, The Octopus, The Sea, and the Deep Origins of Consciousness. So, no, this isn’t a business book. It is more of an ‘expand your perspectives book’ or a ‘think outside the box book.’ For the author, Peter Godfrey-Smith, I give him my highest compliment: This book is extremely thought provoking.
I love to read. I tend to have ‘reading in bed books’ and ‘reading at my desk books.’ The difference is that ‘reading at my desk books’ are more intellectually challenging, causing me to want to take notes. This book, Other Minds, transitioned from bed to desk. In fact, I ended up reading most chapters twice, as the content was so challenging and thought provoking. It is extremely well written; that isn’t the challenge. The challenge is how hard this book makes one think.
The author is a philosopher, but also a diver and amateur biologist. His thinking about what it means to be conscious are informed by his observations of other creatures, especially the cephalopods, which includes octopuses, cuttlefish and squid. Octopuses are the main stars in this story with a strong supporting role played by cuttlefish. Both are amazing creatures.
The book takes us through the history of life on Earth from single-celled organisms to multi-celled creatures to animals with nervous systems. During the well-known Cambrian explosion, predation begins and the interplay between predators and prey helped shape the development of nervous systems.
You might have heard that octopuses can unscrew a jar. Did you know they can fit through a hole slightly larger than their eye? With no skeleton or exoskeleton, their bodies can take on almost any shape. Unlike fish, an octopus knows it is in a tank when they are studied in a lab. They will squirt water at people they don’t like, meaning they recognize faces. They will also wait until they aren’t being watched to escape.
Clearly, they are intelligent beings. Humans have about 100 billion neurons in their bodies, while octopuses have about 500 million. This is about the same as dogs, but the comparison isn’t valid. That’s because the cephalopods developed completely independently of vertebrates. Our common ancestor was a simple flat worm with no brain and a small nervous system. The branching off from that common ancestor occurred about 600 million years ago.
The species closest to humans, those with large brains, include chimps, dolphins, dogs and cats. All these creatures have a lizard as their common ancestor. But cephalopods diverged much earlier. They are an independent experiment in the evolution of large brains and complex behavior. The author says they are probably the closest we will come to meeting an intelligent alien.
Being on a separate evolutionary track, the cephalopods’ brains developed differently than vertebrates. For cephalopods, they have central brains but also have brains in their limbs. For example, an octopus’s arms each have a brain capable of directing the arm, touching and tasting, independent of the central brain. The central brain can also direct the arms. They have a mixture of localized and top-down control.
Cephalopods also are masters of disguise. This is especially true of cuttlefish, who can change color, pattern and shape almost instantly to disguise themselves. Parts of a cuttlefish can match one background while another part of the animal matches a separate background. Or, they can create a whole-body color, probably as a signal to other cuttlefish or predators.
That would be amazing enough, but cephalopods, while having eyes structured similar to vertebrates, are colorblind. How do they match the color to their surroundings? They are able to see with their skin. They have receptors and pigment packets in their skin. The skin even functions when removed from the animal. Cuttlefish also have rudimentary brains, or bunches of neurons in their legs called ganglia, allowing independent direction of each leg. And octopuses can change color, just not as dramatically as a cuttlefish. Clearly, the intelligence we have as humans isn’t the only kind of intelligence.
A few months ago, I wrote about a family trip to Korea where we ate octopus, cuttlefish and squid. The octopus’ legs were still moving and now I know why. It makes me feel a bit guilty to have eaten these intelligent animals while they were still alive.
The book’s author makes the point that all life started in the sea. We are able to live on land only because we lug around a lot of water-filled cells, where the complex processes of life occur. Those cells contain the remnants of the oceans. The oceans we are destroying. The book is dedicated to those who are working to protect those oceans.
If you’re intrigued enough to want to learn more, you can read the book, which I recommend. There are also some good lectures by Peter Godfrey-Smith to be found on YouTube.
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