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Broadclub cuttlefish, Sepia latimanus.
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‘Metazoa’ Review: Marine Minds
From octopus intelligence to scientific shrimp, a probe for the animal origin of selfhood.
By Barbara Kiser
November 6, 2020
Life undersea has a mesmerizing strangeness, from glass sponges—lacy matrices draped with cellular nets—to rococo sea dragons and soft corals like trees in a slow wind. It’s the stuff of a thousand documentaries, but for Peter Godfrey-Smith the spectacle is a curtain-raiser to a profound scientific drama, in which the lives of quite un-human creatures illuminate deep mysteries about the nature of sentience, and what it means to possess a mind.
In “Metazoa,” the scuba-diving historian and philosopher of science tackles these questions with eloquent boldness, reminding us that “life and mind began in water.” Mr. Godfrey-Smith continues the journey he began in “Other Minds” (2016), which focused on the octopus, the closest we have to an “intelligent alien”: an invertebrate with a big, complex nervous system and capacities for play and adaptation. Now he expands the exploration to multicellular animals as a group—the Metazoa of the title—homing in on those marking key transitions in the evolution of mind.
As a biological materialist, Mr. Godfrey-Smith sees consciousness as an evolutionary product emerging from the organization of a “universe of processes that are not themselves mental.” He makes no claim to having cracked the conundrum of how meat gives rise to mind. Instead, to get under the skins of his slithering, bobbing subjects, he builds evidence from the evolutionary record to create a picture of the “different forms of subjectivity around us now.” “Metazoa” sweeps readers from Aristotle through the Darwinian revolution and on to current research into the origins of life, spider cognition, the evolution of warm-bloodedness and beyond. He also revisits philosopher Thomas Nagel’s “What Is It Like to Be a Bat?,” the 1974 essay that famously probed the primal difficulties of understanding subjective experience in other organisms.
As in “Other Minds,” Mr. Godfrey-Smith recounts close encounters with marine fauna, gleaned from years of diving off the Australian coast. These have an electric immediacy: He’s often as much observed as observing. At one point he is hovering over a field of starfish when a seal comes in fast, then shoots away “curling and surging through space” to leave him “down there among the stars.” At another, a red-and-white-striped banded shrimp, one limb raised like “a tiny maestro,” looks him full in the face.
These immersive moments become springboards into investigations of metazoans over some 800 million years of evolution, using available records and animals now alive as guides. The tree of life (first theorized by Darwin, now more tangled) punctuates the text to clarify ancestry and descent and, importantly, show how all organisms alive now, from ants to us, sit at its top. (The author is careful to point out that the scala naturae—the representation that puts humans on the uppermost rung of a ladder, above other animals—is long defunct.)
From sponges and corals, “remnants and relatives of early forms of animal action,” Mr. Godfrey-Smith glides on through arthropods, cephalopods, fish and the creatures that eventually clambered onto land. In each group, he probes the complex effects of evolutionary innovations. Nervous systems, which probably first emerged as simpler neural nets more than 600 million years ago, tie “the body together in new ways”: Neurons have thousands of synapses, enabling vast interconnectivity. The emergence of bilaterally symmetrical bodies allowed movement with direction and traction—a big step.
Soft corals, for instance, can open, clench and fire stinging cells thanks to nerve nets and muscles. Arthropods are more formidably equipped. A phylum emerging in the Cambrian “explosion” some 540 million years ago, it now spans insects, crustaceans, arachnids and more, beasts with image-forming eyes and exoskeletons as well as nervous systems and bilateral symmetry. A shrimp’s “toolkit” of complex limbs allows it to “poke and interfere and make the world talk back”; it richly experiences the distinction between self and environment. From such experimentation, Mr. Godfrey-Smith posits, a point of view arises—a “new way of being in the world” that, while probably not “a turning on of the experiential lights,” is something like subjectivity.
As nervous systems evolved further, other kinds of activity and integration arose. Octopuses, revisited here, are a compelling case. Two-thirds of the cephalopod’s half-billion neurons are lodged in its eight arms, part of a “distributed brain’” that may help in controlling its shape-shifting body. Combining his observations with findings on the animals’ behavioral complexity and sensitivity, engagement with novelty, play and problem-solving, Mr. Godfrey-Smith sees octopuses as conscious, although their perspective is probably “protean and perhaps sometimes chaotic.”
In fish we meet vertebrates with muscle, motion, jaws—and another sensory paradigm. The special cells called neuromasts that form their “lateral line” system sense pressure and vibration, and together act, in Mr. Godfrey-Smith’s evocative phrase, as a “giant pressure-sensitive ear.” In the lab, carp have distinguished between classical music and blues, and even between artists such as John Lee Hooker and Sonny Boy Williamson. Mr. Godfrey-Smith speculates that this capacity for pattern recognition might emerge from gregariousness—the complexity of fishes’ social environments giving rise to memory and recognition skills.
No marine animal, however, evolved with “a capacity for manipulation, openness of bodily action, and centralized braininess” all at once. That key mix came with land vertebrates: It arose in mammals and early dinosaurs independently, was transformed again in birds (“the dinosaurs who survived”), and emerged again in primates. Looking back at these immense journeys, Mr. Godfrey-Smith asserts a gradualism in the development of mind. In evolution, key traits don’t pop up suddenly: They “creep into being.” If these traits are the basis for subjective experience across animals, mind too is a case of more or less rather than present or non-present, lights on or off. Its “thereness is a matter of degree.”
This view has obvious implications for how we see, and treat, other organisms. It also militates against current theories on “strong” artificial intelligence (AI). If we accept that consciousness is tethered to specific biological bases, the idea of an uploadable self is fantasy. AI subjectivity or agency is, so far, illusory. Strong AI programs, argues Mr. Godfrey-Smith, might represent some kinds of brain activity, but they cannot fully replicate what brains do: Aside from structural differences, they lack a brain’s large-scale dynamic features—its patterns and rhythms.
The passages in “Metazoa” on those dynamic features, such as synchronized “electrical breathing” in neurons, are gripping—as are the discussions of pain in hermit crabs, split-brain cognition and REM sleep in cuttlefish. The sheer number of exploratory pathways, the author admits, give the book a “tentacular” form. I also found one or two of the philosophical passages somewhat viscous—like mud-wrestling an octopus.
Debate, of course, still rages around the very use of such terms as “consciousness” in the non-human context. The idea that consciousness is impossible without a cerebral cortex (a feature mammals share but most animals featured in “Metazoa” lack) is still afloat. Some who look at the “layout of mind in the world,” Mr. Godfrey-Smith notes, perceive a jungle, with sentience everywhere; others see a desert, with humans in sole possession. To him, it is somewhere between.
“Metazoa” begins in a marine garden of sponges, swaying and shrugging as Mr. Godfrey-Smith drifts past. At the end he enters another kind of garden: the human mind. We are part of life’s astonishing prodigality, even carrying “the sea with us in all our cells.” If manifold forms of sentience have emerged from this richness, it should perhaps not surprise us.
—Ms. Kiser is a London-based writer and editor, and the former commissioning editor for books and arts at Nature.
Copyright ©2020 Dow Jones & Company, Inc. All Rights Reserved.
Appeared in the November 7, 2020, print edition as 'Deep Thinking.'
BOOKSHELF
‘Metazoa’ Review: Marine Minds
From octopus intelligence to scientific shrimp, a probe for the animal origin of selfhood.
By Barbara Kiser
November 6, 2020
Life undersea has a mesmerizing strangeness, from glass sponges—lacy matrices draped with cellular nets—to rococo sea dragons and soft corals like trees in a slow wind. It’s the stuff of a thousand documentaries, but for Peter Godfrey-Smith the spectacle is a curtain-raiser to a profound scientific drama, in which the lives of quite un-human creatures illuminate deep mysteries about the nature of sentience, and what it means to possess a mind.
In “Metazoa,” the scuba-diving historian and philosopher of science tackles these questions with eloquent boldness, reminding us that “life and mind began in water.” Mr. Godfrey-Smith continues the journey he began in “Other Minds” (2016), which focused on the octopus, the closest we have to an “intelligent alien”: an invertebrate with a big, complex nervous system and capacities for play and adaptation. Now he expands the exploration to multicellular animals as a group—the Metazoa of the title—homing in on those marking key transitions in the evolution of mind.
As a biological materialist, Mr. Godfrey-Smith sees consciousness as an evolutionary product emerging from the organization of a “universe of processes that are not themselves mental.” He makes no claim to having cracked the conundrum of how meat gives rise to mind. Instead, to get under the skins of his slithering, bobbing subjects, he builds evidence from the evolutionary record to create a picture of the “different forms of subjectivity around us now.” “Metazoa” sweeps readers from Aristotle through the Darwinian revolution and on to current research into the origins of life, spider cognition, the evolution of warm-bloodedness and beyond. He also revisits philosopher Thomas Nagel’s “What Is It Like to Be a Bat?,” the 1974 essay that famously probed the primal difficulties of understanding subjective experience in other organisms.
As in “Other Minds,” Mr. Godfrey-Smith recounts close encounters with marine fauna, gleaned from years of diving off the Australian coast. These have an electric immediacy: He’s often as much observed as observing. At one point he is hovering over a field of starfish when a seal comes in fast, then shoots away “curling and surging through space” to leave him “down there among the stars.” At another, a red-and-white-striped banded shrimp, one limb raised like “a tiny maestro,” looks him full in the face.
These immersive moments become springboards into investigations of metazoans over some 800 million years of evolution, using available records and animals now alive as guides. The tree of life (first theorized by Darwin, now more tangled) punctuates the text to clarify ancestry and descent and, importantly, show how all organisms alive now, from ants to us, sit at its top. (The author is careful to point out that the scala naturae—the representation that puts humans on the uppermost rung of a ladder, above other animals—is long defunct.)
From sponges and corals, “remnants and relatives of early forms of animal action,” Mr. Godfrey-Smith glides on through arthropods, cephalopods, fish and the creatures that eventually clambered onto land. In each group, he probes the complex effects of evolutionary innovations. Nervous systems, which probably first emerged as simpler neural nets more than 600 million years ago, tie “the body together in new ways”: Neurons have thousands of synapses, enabling vast interconnectivity. The emergence of bilaterally symmetrical bodies allowed movement with direction and traction—a big step.
Soft corals, for instance, can open, clench and fire stinging cells thanks to nerve nets and muscles. Arthropods are more formidably equipped. A phylum emerging in the Cambrian “explosion” some 540 million years ago, it now spans insects, crustaceans, arachnids and more, beasts with image-forming eyes and exoskeletons as well as nervous systems and bilateral symmetry. A shrimp’s “toolkit” of complex limbs allows it to “poke and interfere and make the world talk back”; it richly experiences the distinction between self and environment. From such experimentation, Mr. Godfrey-Smith posits, a point of view arises—a “new way of being in the world” that, while probably not “a turning on of the experiential lights,” is something like subjectivity.
As nervous systems evolved further, other kinds of activity and integration arose. Octopuses, revisited here, are a compelling case. Two-thirds of the cephalopod’s half-billion neurons are lodged in its eight arms, part of a “distributed brain’” that may help in controlling its shape-shifting body. Combining his observations with findings on the animals’ behavioral complexity and sensitivity, engagement with novelty, play and problem-solving, Mr. Godfrey-Smith sees octopuses as conscious, although their perspective is probably “protean and perhaps sometimes chaotic.”
In fish we meet vertebrates with muscle, motion, jaws—and another sensory paradigm. The special cells called neuromasts that form their “lateral line” system sense pressure and vibration, and together act, in Mr. Godfrey-Smith’s evocative phrase, as a “giant pressure-sensitive ear.” In the lab, carp have distinguished between classical music and blues, and even between artists such as John Lee Hooker and Sonny Boy Williamson. Mr. Godfrey-Smith speculates that this capacity for pattern recognition might emerge from gregariousness—the complexity of fishes’ social environments giving rise to memory and recognition skills.
No marine animal, however, evolved with “a capacity for manipulation, openness of bodily action, and centralized braininess” all at once. That key mix came with land vertebrates: It arose in mammals and early dinosaurs independently, was transformed again in birds (“the dinosaurs who survived”), and emerged again in primates. Looking back at these immense journeys, Mr. Godfrey-Smith asserts a gradualism in the development of mind. In evolution, key traits don’t pop up suddenly: They “creep into being.” If these traits are the basis for subjective experience across animals, mind too is a case of more or less rather than present or non-present, lights on or off. Its “thereness is a matter of degree.”
This view has obvious implications for how we see, and treat, other organisms. It also militates against current theories on “strong” artificial intelligence (AI). If we accept that consciousness is tethered to specific biological bases, the idea of an uploadable self is fantasy. AI subjectivity or agency is, so far, illusory. Strong AI programs, argues Mr. Godfrey-Smith, might represent some kinds of brain activity, but they cannot fully replicate what brains do: Aside from structural differences, they lack a brain’s large-scale dynamic features—its patterns and rhythms.
The passages in “Metazoa” on those dynamic features, such as synchronized “electrical breathing” in neurons, are gripping—as are the discussions of pain in hermit crabs, split-brain cognition and REM sleep in cuttlefish. The sheer number of exploratory pathways, the author admits, give the book a “tentacular” form. I also found one or two of the philosophical passages somewhat viscous—like mud-wrestling an octopus.
Debate, of course, still rages around the very use of such terms as “consciousness” in the non-human context. The idea that consciousness is impossible without a cerebral cortex (a feature mammals share but most animals featured in “Metazoa” lack) is still afloat. Some who look at the “layout of mind in the world,” Mr. Godfrey-Smith notes, perceive a jungle, with sentience everywhere; others see a desert, with humans in sole possession. To him, it is somewhere between.
“Metazoa” begins in a marine garden of sponges, swaying and shrugging as Mr. Godfrey-Smith drifts past. At the end he enters another kind of garden: the human mind. We are part of life’s astonishing prodigality, even carrying “the sea with us in all our cells.” If manifold forms of sentience have emerged from this richness, it should perhaps not surprise us.
—Ms. Kiser is a London-based writer and editor, and the former commissioning editor for books and arts at Nature.
Copyright ©2020 Dow Jones & Company, Inc. All Rights Reserved.
Appeared in the November 7, 2020, print edition as 'Deep Thinking.'
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