Peter Godfrey-Smith

Although mammals and birds are widely regarded as the smartest creatures on earth, it has lately become clear that a very distant branch of the tree of life has also sprouted higher intelligence: the cephalopods, consisting of the squid, the cuttlefish, and above all the octopus. In captivity, octopuses have been known to identify individual human keepers, raid neighboring tanks for food, turn off lightbulbs by spouting jets of water, plug drains, and make daring escapes. How is it that a creature with such gifts evolved through an evolutionary lineage so radically distant from our own? What does it mean that evolution built minds not once but at least twice? The octopus is the closest we will come to meeting an intelligent alien. What can we learn from the encounter? In Other Minds, Peter Godfrey-Smith, a distinguished philosopher of science and a skilled scuba diver, tells a bold new story of how subjective experience crept into being—how nature became aware of itself. As Godfrey-Smith stresses, it is a story that largely occurs in the ocean, where animals first appeared. Tracking the mind’s fitful development, Godfrey-Smith shows how unruly clumps of seaborne cells began living together and became capable of sensing, acting, and signaling. As these primitive organisms became more entangled with others, they grew more complicated. The first nervous systems evolved, probably in ancient relatives of jellyfish; later on, the cephalopods, which began as inconspicuous mollusks, abandoned their shells and rose above the ocean floor, searching for prey and acquiring the greater intelligence needed to do so. Taking an independent route, mammals and birds later began their own evolutionary journeys. But what kind of intelligence do cephalopods possess? Drawing on the latest scientific research and his own scuba-diving adventures, Godfrey-Smith probes the many mysteries that surround the lineage. How did the octopus, a solitary creature with little social life, become so smart? What is it like to have eight tentacles that are so packed with neurons that they virtually “think for themselves”? What happens when some octopuses abandon their hermit-like ways and congregate, as they do in a unique location off the coast of Australia? By tracing the question of inner life back to its roots and comparing human beings with our most remarkable animal relatives, Godfrey-Smith casts crucial new light on the octopus mind—and on our own.

The Octopus, the Sea, and the Deep Origins of Consciousness

Other Minds

Dhrumil Patel

In all but a few animals, the chemical interactions between some cells become the basis for a nervous system, small or large. And in some of these animals, a mass of such cells concentrated together, sparking in a chemo-electrical storm of repurposed signaling, become a brain.

Neurons cost a grecat deal of energy to run and maintain. Creating their electrical spasms is like the continual charging and discharging of a battery, hundreds of times cach second. In an animal like us, a large proportion of the energy taken in as food, nearly a quarter in our case, is spent just keeping the brain running.

The history of life is a history of intermediates, shadings-off, and gray areas.

The evolution of muscle, derived from tiny fiber-like elements inside cells, created a new means by which life impresses itself on the world. All living things affect their environment by making and transforming chemicals, and also by growing and sometimes by moving, but it is muscle that gives rise to rapid, coherent action on large spatial scales.

To some degree, unity is inevitable in a living agent: an animal is a whole, a physical object keeping itself alive. But in other ways, unity is optional, an achievement, an invention. Bringing experience together—even the deliverances of the two eyes—is something that evolution may or may not do.

How animals change color: The skin has an outer layer, a dermis, that acts as a covering. The next layer down contains the chromatophores, the most important of the color-control devices. A single chromatophore unit contains several different kinds of cells. One cell holds a sac of a colored chemical. Around it are muscle cells, one or two dozen of them, which pull the sac into different shapes. Those muscles are controlled by the brain. They stretch the sac to make its color visible, or relax it for the opposite effect.

David Hume in an attempt to find his self: "I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception." These sensations or perceptions, he said, comprise him — nothing more. A person is just a bundle or collection of images and feelings, "which succeed each other with an inconceivable rapidity, and are in a perpetual fux and movement."

Why don't cephalopods live for a longer time? Why don't we all live for a longer time? On mountainsides in California and Nevada there are pine trees that were alive when Julius Caesar was wandering around Rome. Why do some organisms live for dozens, hundreds, or thousands of years while others, in the natural course of events, do not see even a single year pass?

The mind evolved in the sea. Water made it all possible. When you dive into the sea, you are diving into the origin of us all.

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