Thus most amazing: recognition, their “sense of mutual engagement,” their disarming friendliness. “You reach forward a hand and stretch out one finger, and one octopus arm slowly uncoils . . . tasting your finger as it draws it in. . . . Behind the arm, large round eyes watch.”
Godfrey-Smith watched his dive partner as “an octopus grabbed his hand and . . . Matt followed, as if he were being led across the sea floor by a very small eight-legged child.” Ten minutes later they arrived at the octopus’s den.
Octopuses have personality (cephonality?), some shy, some confident or “particularly feisty.” Some — not all — play, blowing and batting bottles around. They recognize human faces; one study confirmed that giant Pacific octopuses could even distinguish people wearing identical uniforms. Octopuses become fond of certain people, yet at others they squirt disdainful jets of water. One cuttlefish squirted all new visitors, but not familiar faces. (Giant cuttlefish look “like an octopus attached to a hovercraft” and seem “to be every color at once.”) So, like humans, cephalopods can categorize. Some squirt their lights out at night, short-circuiting them. They “have their own ideas.”
The search for intelligent life starts astonishingly far back. Even bacteria sense and respond to the world, though that’s most likely analogous to motion detectors rather than anything felt. Still, their complexity is mind-blowing. To approach the nutritious and avoid the noxious, the author says, a bacterial cell “uses time to help it deal with space. . . . One mechanism registers what conditions are like right now, and another records how things were a few moments ago. The bacterium will swim in a straight line as long as the chemicals it senses seem better now than those it sensed a moment ago. If not, it’s preferable to change course.”
Much later, multicelled gelatinous animals evolved neurons. Nerves underneath coordinated cells’ “tiny contractions, contortions and twitches” into propulsive pulsing. Other nerves wired light-sensing organs above to coordinate day-night rhythms. The motion-controlling system may have eventually entangled the light sensors, whence light sensors aided motion guidance. Thus neurons convened into a “chemo-electrical storm of repurposed signaling” — brains. (Deadly evidence: Box jellyfish, some of whose two dozen eyes have lenses and retinas like ours, can navigate by watching landmarks on the shore as they pulse along at three knots.)
Then, a half-billion years ago, Cambrian animals first watched, seized and fled other animals. Senses, nervous systems and behaviors escalated an arms race against the senses and behaviors of others. If a yardlong cockroach-looking appetite with two graspers on its head is swimming rapidly at you, “it’s a very good thing to know, somehow, that this is happening, and to take evasive action.” With better sensory processing and a need for decisions (fight or flee), the Cambrian delivered Earth’s first information revolution. “From this point on,” Godfrey-Smith emphasizes, “the mind evolved in response to other minds.”
Amid explosive evolution, you’d assume that speedy, grasping creatures evolved often. Surprisingly, of about 34 basic animal body plans (phyla), only arthropods (insects, crabs), vertebrates and one subgroup among mollusks — cephalopods — evolved “complex active bodies.” Only vertebrates and cephalopods developed large, complex nervous systems.
Contrary to some philosophers’ assumptions, consciousness doesn’t just project out; it is a relationship in traffic with the outer world. Consciousness did not “suddenly irrupt into the universe fully formed,” Godfrey-Smith says. “Perception, action, memory — all those things creep into existence from precursors and partial cases.” Asking whether bacteria perceive or bees remember “are not questions that have good yes-or-no answers.” From minimal to elaborate sensing there’s a continuum, “and no reason to think in terms of sharp divides.”
How then did feeling begin? Rudimentarily, Godfrey-Smith asks: “Does damage feel like anything to a squid?” Does injury feel bad to a lobster or a bee? Well, insects don’t groom or protect injured parts of their bodies. But injured crabs, shrimp and octopuses do. Injected with a chemical thought to spark pain, zebra fish prefer water with a dissolved painkiller; so yes, fish feel pain. Godfrey-Smith says pain, hunger, thirst and other “primordial emotions” do not require worldviews. If they are felt, this by definition is sentience.
If this is philosophy, it works, because Godfrey-Smith is a rare philosopher who searches the world for clues. Knowledgeable and curious, he examines, he admires. His explorations are good-natured. He is never dogmatic, yet startlingly incisive. His refreshing guidance invites us, allowing breathing room, to consider, occasionally to respectfully disagree.
Nervous systems compose “a symphony of tiny cellular fits, mediated by sprays of chemicals across the gaps where one cell reaches out to another.” Most basically, brains coordinate muscles into motion. In separate elaborations they process and integrate sensory inputs and unify worldly orientation, managing biorhythms and hormones. When surviving requires decision making, brains have developed awareness. “Sentience,” Godfrey-Smith writes, “has some point to it.”
Still, we’re left pondering the “why” of awareness. We can register words flashed so quickly we’re unaware of seeing them. Certain brain-damaged people respond to “visual” stimuli without vision. Painstaking practice facilitates execution of complex musical passages using unconscious muscle memory. This twilight zone is fascinating. Future work will probably reveal the neural circuitries involved.
Language isn’t required. As Godfrey- Smith notes, “very complex things go on inside other animals without the aid of speech.” Monkeys, elephants and many others understand their social world with detailed complexity and nuance beyond anything they could say about it.
Octopuses have existed over a thousand times longer than humans. The sea is the original birthplace of the mind. “When you dive into the sea, you are diving into the origin of us all,” Godfrey-Smith writes. Ancient. But not timeless. The author has dedicated his book to “all those who work to protect the oceans.” That says much. As we change the world, let’s bear this in our minds: Other minds are living their own lives here with us on Earth.