Book Review: Other Minds

3 minute read


Peter Godfrey-Smith’s Other Minds is a book about octopuses. It is also a book about evolution and conciousness. Starting at the intimate contact between a scuba diver and an octopus, the book journeys in and out of the ocean, backwards through millions of years of time, and concludes with comments on the future of the sea.

Here’s the paperback and audiobook.

Utility: ⭐⭐⭐ (3/5)

I learned a surprising amount about evolution, physiology, philosophy, and marine biology. The book provided useful reframings of conciousness that are fascinating and personally enriching. I feel more closely connected to the sea.

Writing: ⭐⭐⭐⭐ (4/5)

Peter (not me) is a talented writer. He is clear and compelling, blending narrative with analysis. He skillfully transmit his empathy with the cethalopods—he “befriends” many—to the reader. A wonderful and wretched distraction from studying for my finals.


Evolutionary History

Single-celled life emerged billions of years ago. The Cambrian explosion marked distinct body plans, including bilaterals, which encompass most intelligent life forms today. A fork emerged between vertibrates (like us) and invertibrates (like the octopus); among the invertibrates, only the cethelapods are known for a human-like intelligence. This simultaneous similarity and evolutionary distance makes them alien.

The Origins of Conciousness

Technically, even bacteria respond to the environment, responding to light and chemicals. But for complex bodies, the nervous system was necessary. Whereas some focus on a perception-action model of conciouness, the nervous system also supports the role of coordination: lining up countless little movements to produce an action in the first place. The first nervous system may have been designed for movement alone.

Subjective experience is a better word than conciousness. It’s not likely that something like human conciouness just appeared. Instead, conciouness transformed from an unintelligible white noise, slowly gaining granularity and culminating in the higher-order thought familiar with humans.

The Octopus

The octopus, and other cethalopods, have sensory-motor coupling. Their nervous systems are dispersed, with many nuerons in their arms. Each arm supports some independence, although octopuses seem to be able to enact executive control. sensorimotor

Coloration, as in the cuttlefish, is another example. Layers of cells emit different colors of light, allowing cethalopods to blend in, confuse a pedator, or attract a mate. All of this while they are colorblind! Experiments suggests nuerons in the arms provide an answer.

Octpuses die young, often living only to two. Senescence—the process of aging and dying–is explained by evolutionary pressures. If an animal will eventually die from external causes, then evolution will favor mutations that benefit the early stages of life, even if they produce harmful effects in the old.

Our Minds and Others

The global workspace theory makes much more sense if concieved of as a broadcast system, uniting streams of perception.

Despite complex colorations, cethalopods don’t seem to communicate much. Godfrey-Smith’s studies suggest that dark colors fortell aggression, while pale colors communication submission—at least among a group of octopuses in his “Octopolis” observing spot.

But language is overstated as essential for coherence. Babboons can keep track of sophistical social lives with only 3 or 4 calls. Deaf people in societies without sign language function fine.