Peter Godfrey-Smith is besotted with cephalopods. These enigmatic and generally solitary sea-dwellers include octopuses, cuttlefish and squid, all of which have big and complex brains and act in ways that suggest alien minds. A philosopher of science and experienced deep-sea diver, Godfrey-Smith has rolled his obsessions into one book, weaving biology and philosophy into a dazzling pattern that looks a lot like the best of pop science.
He peppers his latest book with vivid anecdotes from his cephalopod encounters: "I saw something moving under a ledge — something surprisingly large — and went down to look at it. What I found looked like an octopus attached to a hovercraft.… The animal seemed to be every color at once — red, grey, blue-green. Patterns came and went in a fraction of a second. Amid the patches of color were veins of silver like glowing powerlines. The animal hovered a few inches above the seafloor, and then came forward to look at me."
Of this particular cuttlefish, he says, "This was my first experience with an aspect of these animals that has never stopped intriguing me: the sense of mutual engagement that one can have with them."
Godfrey-Smith relates dramatic stories of mischief made by captive octopuses and spends a delightful chapter exploring cephalopods' sophisticated color-changing abilities ("a kind of ongoing chromatic chatter"), but this is not narrative nonfiction about the secret life of cephalopods, along the lines of Sy Montgomery's "The Soul of an Octopus." This is a gifted philosopher and historian of science doing philosophy with octopuses. His project is no less ambitious than to work out the evolutionary origins of subjective experience.
In philosophy, the problem of other minds is a time-honored and unresolved conundrum: how to justify the almost universal belief that other humans have minds much like our own, including a rich inner life. Here, in unadorned language that makes complex ideas readily accessible, Godfrey-Smith asks why subjective experience should have arisen in life on our planet at all.
Starting with single-celled organisms swimming in the primordial sea, Godfrey-Smith tells an incredibly compact and lucid history of the evolution of the nervous system, offering an account of what he sees as the material conditions underlying the evolution of consciousness.
There are two key concepts here, both involving feedback loops. The first is feedback between sensing and acting, and the second is feedback between an organism and its environment, including other organisms. "In the transition to the first animals with nervous systems, the [single-celled] machinery of external sensing and signaling was turned inward, enabling coordination within these new larger living units… Organisms became entangled in each other's lives in new ways, especially as predator and prey."
He firmly anchors his investigation in cephalopods because "Cephalopods and smart vertebrates are independent experiments in the evolution of the mind."  Our last common ancestor probably lived about 600 million years ago and "had the form of small, flattened worms," which means that after these branches of the evolutionary tree diverged, complex nervous systems and the kinds of minds they enable evolved at least twice, in parallel. Probably three times, as octopuses' last common ancestor with other cephalopods lived 270 million years ago.
And so we arrive in the present. Of his experiences with octopuses, he notes: "if you sit in front of their den and reach out a hand, they'll often send out an arm or two, first to explore you, and then — absurdly — to try to haul you into their lair."
In this elegantly materialist telling, subjective experience is deeply embodied in physical form. Most of a cephalopod's neurons are not clustered in a centralized brain, as in vertebrates, but located in the arms, which seem to have some degree of autonomy. "For an octopus, its arms are partly self – they can be directed and used to manipulate things. But from the central brain's perspective they are partly non-self too, partly agents of their own." This is as alien a mind as we could hope to encounter. Godfrey-Smith posits a consciousness that remains rooted in top-down control from the central brain, like an orchestra conductor giving cues to jazz musicians, but one can't help wondering: what if cephalopod experience is weirder than that? What might it be like for subjective experience to be plural — "we" and "not-we."
Godfrey-Smith, whose previous books include "Theory and Reality: An Introduction to the Philosophy of Science," "Philosophy of Biology" and "Darwinian Populations and Natural Selection" (which won the 2010 Lakatos Award), is well-versed in writing accessible entry points to complex ideas in philosophy and biology. Here, he delivers philosophy wrapped even more firmly in the glittering cloak of popular science. The result is an incredibly insightful and enjoyable book that draws on thinkers like Hume, John Dewey and the lesser-known Soviet-era psychologist Lev Vygotsky, as well as research from the fossil record, evolutionary biology and a wide range of animal cognition studies without ever falling into some of the more lamentable pitfalls of the popular science genre — condescending to the reader or oversimplifying the science.
"The mind evolved in the sea," writes Godfrey-Smith, but if water is our origin, it may also be our destiny. Humans burning fossil fuels has led to rising levels of water in the atmosphere, which is causing increasingly extreme weather events such as catastrophic floods and droughts. According to the Pentagon's 2014 Climate Change Adaptation Roadmap, "Rising global temperatures, changing precipitation patterns, climbing sea levels, and more extreme weather events will intensify the challenges of global instability, hunger, poverty, and conflict. They will likely lead to food and water shortages, pandemic disease, disputes over refugees and resources, and destruction by natural disasters in regions across the globe." A week ago, Arctic temperatures were running 35 degrees above average, and sea ice that should be freezing in November was, astoundingly, melting. Godfrey-Smith gestures to the climate crisis in the final pages of "Other Minds," writing, "Our ability to manage this is hampered not just by greed and competing interests, but by the difficulty of getting a handle on the problem and understanding our own destructive capacities." Whatever happens next — whatever we do with the consciousness enabled by these big brains of ours — we can't say we weren't warned.
When he considers the short life span of most cephalopods, he wonders, poignantly, "what is the point of building a large nervous system if your life is over in a year or two?" While he poses this question from an evolutionary perspective ("The machinery of intelligence is expensive, both to build and to run"), it leads quickly to the edge of a precipitous existential abyss: "What is the point of investing in a process of learning about the world if there is almost no time to put that information to use?"
Crist is writer-in-residence in biological sciences at Columbia University.
What: Peter Godfrey-Smith with Amy Parish
Where: ALOUD at the L.A. Central Library, 630 W. 5th St., Los Angeles
When: 7:15 p.m. Dec. 7
Price: Free, standby only