1SHARK BAY
Driving
We got back into the car for the drive away from Shark Bay. This bay is right on the western tip of Australia, where the continent looks out across the Indian Ocean toward Africa. In the clear, extra-salty water of the shallows are what appear for a moment to be hundreds of outsized aquatic mushrooms, their heads perhaps a foot or so in diameter. They are interconnected, forming an irregular landscape of shapes and channels, sometimes nudging above the water, sometimes submerged.
The mushroom-like clumps are made up, in part, of microorganisms, including countless cyanobacteria. These are tiny, nondescript, and pivotal in the history of the Earth. Specifically, they are pivotal in the transformation of the Earth by one of its products: life.
Cyanobacteria (pronounced with a soft “c,” as in the color cyan: sy-an-o-bacteria) are an old group of organisms. Sometime around 3 billion years ago, they or their ancestors invented a particular kind of photosynthesis. Like other kinds of photosynthesis, this process uses energy from the sun to power the building of living material. But in this case, oxygen gas is released as a byproduct—the oxygen that animals like us breathe.
Standing above the bay, taking in oxygen from the dry Western Australian air, we had organisms like these to thank. Pulling in carbon dioxide, breaking water molecules apart with the power of light, splicing the elements to build living material, and releasing oxygen gas in tiny puffs, they slowly transformed the atmosphere, and the planet along with it, until Earth could power the organic engines of animal life—muscles, nervous systems, brains.
The cyanobacteria colonies at Shark Bay are themselves thousands of years old. The mushroom-like mounds are called stromatolites, and this is the largest living stromatolite system in the world. Small fish, tails flicking, threaded through the maze of channels—beneficiaries, like us, of the atmosphere those tiny, ancient cells had generated.
* * *
We drove away on a road framed by red-orange earth. The land looks rusted. It is rusted—that is exactly what has happened. Redness in earth and rock is usually due to an interaction between oxygen and iron: iron oxide, rust. When the cyanobacteria started breathing out oxygen, initially it did not accumulate in the atmosphere. Much of it reacted with rocks, which contained various elements, including iron, waiting to take it up. Red desert landscapes were painted, and are still being repainted, by life in this way. The particular stretch of red rushing past our car was most likely laid down by later oxygen-producers, but cyanobacteria started the process.
Eventually, with this coat of color laid, oxygen started to hang around as gas. Farther north in Western Australia, you reach earth that does not look rusted or red-orange; instead it is intensely red, close to the color of blood—blood that is red in us because of the same bonding of oxygen and iron.
Cyanobacteria also became the germ of forests, as trees and other green plants contain domesticated descendants of those tiny organisms. The cells in a forest leaf are descended from algae that had engulfed cyanobacteria, and worked with them in building living matter from sunlight, water, and air. Cyanobacterial remnants were still inside those algae when they embarked on the multicelled collaborations that gave rise in time to ferns, pines, oaks, and grasses. The painting of the Earth now saw a spread of green, from plants that exhale oxygen as they grow.
* * *
Animals climbed onto land from the sea, their first home, when the greening of the Earth was in its early stages—mosses, not trees. The animals’ move began with arthropods, the group that includes insects, millipedes, and spiders. Vertebrates and others followed. Plants had made their way from wetlands and liminal places. Once they gained a footing, their solar-paneled towers turned the land into a place where the flows of energy from sun to living matter intensified. With plants and animals came soil, the Earth’s new surface.
Eventually, trees became home to primates, along with birds and other animals. Later still, some of those primates came down and started living on broad savannas. They formed bigger groups and then societies: talking, dancing, building. They forged technologies and social forms, embarked on collaborative projects shaped by reflection and foresight, and eventually reengineered the world as no animal before them had.
As our car rolled along, fuel from its tank ignited with some of the air’s oxygen. The fuel was made from compressed plankton and other marine organisms, settling in still water and then buried many millions of years ago. The car’s steel was made from iron and carbon with the aid of vast amounts of heat, produced by burning other fuels in distant furnaces.
Think again about that sequence—let’s run through it speeded up. Cyanobacteria begin emitting oxygen into the atmosphere. Oxygen drives animal life, first in the sea and later on land. Descendants of cyanobacteria become part of plants. On land, a more intense energy flux evolves in the blazing light, along with a tangle of coevolution between plants and new animals. And then, in our own evolutionary line, an initially unremarkable mammal starts to change in new ways, forming societies and technologies. This leads eventually to change in the atmosphere itself, as carbon that was buried and formed into oil is deliberately burned with life-derived oxygen to push our car along the highway north.
This Book
The history of life includes a parade of new organisms—new bodies and minds, new ways of living—and also a procession of new actions and their effects, new ways that life remakes the world. The history of life is not just a series of new creatures appearing on the stage; the new arrivals change the stage itself.
This book originated as an attempt to work through those themes: the history of action, and the history of how life has changed the Earth. The aim was to see the history of life through that lens or from that angle, to work through a history of organisms as causes, rather than evolutionary products. This gives us, in one sense, an alternative history of life, a history on the what-is-done side, rather than the what-comes-to-exist side. It’s not really another history, though, but an alternative perspective on a single history. The two sides are in there together; the constructive activity of animals and other organisms is part of the history of life on Earth.
Looking through this lens alters our perspective on a lot of things—on animals, on the mind, and on our place here. One result is a dynamic picture of the Earth, a picture of an Earth continually changing because of what living things do. Consider oxygen again. The air we breathe, with its high level of oxygen, is in some ways an “unnatural” atmosphere for a planet like ours. Oxygen is reactive, aggressive, prone to interact with whatever is around it. When scuba diving on “nitrox,” air enriched with extra oxygen, there is a maximum safe depth for each level of oxygen in the gas you are breathing from your tank. Below that level, you will be poisoned by oxygen itself. The oxygen is concentrated by pressure as you descend. The ordinary O2 molecule, although reactive, is not toxic, but oxygen gas, through collisions with itself and everything else, continually gives rise to deviant forms, “oxygen radicals,” and those careen about like electrical wrecking balls. So although diving with enriched air is often a good thing, as you go beyond certain depths, there needs to be less oxygen, proportionally, in the tank. Even the amount of oxygen in ordinary air becomes toxic if you go deep enough. When I was taking a course to learn to dive with nitrox, the manual said, with a hint of poetry, “Oxygen is an unforgiving gas.”
The oxygen-rich atmosphere that we depend on is something that life put in place. It’s not due to “life” in general, though; that concocting of our atmosphere took place through a specific historical path.
Once one starts looking at our planet from a life-as-cause angle, many things look different. The first part of this book, especially, goes down this path. It describes an accumulation of new forms of engineering and transformation, and especially the role of action in this process, along with the minds that guide it.
Whenever minds enter the story, philosophical puzzles follow. One familiar set of puzzles constitutes the classic mind-body problem: How can felt experience or consciousness exist at all in nature? A slightly different question runs beside it: What are minds doing here? What is their place within the totality of the world’s goings-on?
The start of an answer to that second question is that minds—through perceptions, thoughts, plans, and intentions—guide action. Actions serve the interests of organisms, and whether this is intended or not, actions can also transform the world. Deliberate human action continues and extends a long tradition of organisms transforming nature, and the history of the Earth includes a sequence of different forms of such reconstruction. This history begins with single-celled organisms, spans the early evolution of animals and their actions, sees a transition with the move onto land, and extends through to the development of social life, collaboration, and culture. An animal is a nexus where perception and action meet. It’s also a nexus where past meets present, through the traces of the past laid down in memory. Actions, in turn, have consequences beyond the life of the actor, and as minds become more elaborate, they change the reach of animal action. Human action, in its social organization and technical complexity, is one especially powerful form.
This idea of a history that puts minds, especially human minds, into a lineage of transforming agents, and treats those agents as part of the history of the Earth, was the seed of the book and gave rise to its central stem. As that stem extended, other themes branched off from it. Often, a place reached along the main development of ideas offered a vantage point from which some quite distinct topic or question looked different from before.
This includes the traditional mind-body problem itself. Living on Earth is the third book in a series. The first two, Other Minds and Metazoa, were partly about that puzzle. Other Minds was organized around a particular feature of the history of animal life: an ancient split in the genealogical tree, leading on one side to us and on the other side to the octopus, along with many other invertebrate animals. That book was organized around comparisons between our lives and theirs, and used this comparison to explore how minds came to be. The second book, Metazoa, looked at a wider collection of animals and gave a fuller account of the evolution of felt experience. This third book is mainly concerned, as I said, with another side of the story, the mind as cause rather than product (and this book is not written in a way that assumes you have read either of the others). But when we reach humans, the place of our own species in the story, it becomes possible to return to the mind-body relationship and make further progress on it.
We have, I think, mostly moved past “dualist” views that sharply separate mind from body—or so I will assume. I won’t say more in this book about why we should see the mind as a biological phenomenon as opposed to a ghostly addition of some kind. But there is a lot to say about our kind of felt experience, the human kind. Human conscious experience is the product of ancient and broad features of animal life, along with what has happened to our species through language and culture, these peculiarities of our evolutionary line. Felt or conscious experience is probably widespread in animals, and one part of the story of consciousness involves the way that nervous systems make felt experience possible at all. Another part involves what happens in humans and no one else, as far as we know; it involves what came to exist when the eccentricities of human evolution, especially our immersion in culture, came into contact with animal experience, an older phenomenon. The combining of these, the ancient and the new, yields the tangled glories of human consciousness.
* * *
We humans have come out of this long series of events—in evolution, and the shaping of the Earth itself—with minds that feature self-awareness, foresight, and the ability to step back and reflect. We can look out over the whole, and when we do, we find ourselves in the middle of what often feels like a headlong process. The world feels smaller and tighter, with smoke from wildfires unwantedly connecting distant places. Too much of the world, it seems, has come under human influence during a time when we’re not very good at working out how to exercise this power. The portion of Earth occupied by wild nature, its place in the whole, shrinks and recedes.
In the last part of this book I want to think about how we should, or might better, handle some of the choices that confront us. The main topics will be our relationships with nonhuman animals in farming and experimentation, and policy choices around the environment and wild nature—extinction, climate change, and habitat preservation. We’ll turn to the unique challenges of our time, the “Anthropocene.”
The aim of these chapters is not a “biologized ethics,” or a biological moral code. This can be a temptation—trying to directly read a set of moral principles or policies off our scientific picture. I don’t think that if we had a clear and accurate view of us, the Earth, other animals, and so on, it would suddenly be clear what we have to do, or what we should do if we are at all sensible. The view I develop in this area acknowledges a kind of inherent freedom of movement in our situation. But the view of life on Earth, including our lives, outlined in this book can help us make choices. We can reflect on the picture, and then choose our response.
One other theme runs through the book. It is broad and philosophical, and in some ways hard to describe. I left it to this last part of my outline for that reason. As I said a moment ago, this book aims to help us to think about the Earth as a whole, and the role of minds and agency in that whole. I want to defend, in this setting, a kind of ecological outlook. Saying that probably seems quite innocuous. The term “ecological” has various meanings, and often refers to a recognition of connectedness, of whole systems, within the living world. That is fine, and I do intend to convey that, but the point also goes further. I want to defend an orientation that embraces, and stays with, the idea that we, the world’s living agents, are all here together, as parts of a single system. We all have different perspectives on that whole, but we do so while remaining within it and contributing, each in our way, to how it is and how it changes.
I realize that this will still sound very abstract. How else might we think of things? What does this view contrast with? Sometimes in this book, when working through ideas about animal minds, perception, and action, we’ll encounter views that do depart from the ecological mindset I am defending. Especially when writing about perception, both in humans and in other animals, a common tendency has been to move toward a view that installs each animal in a sort of private world. This is a mistake, but it’s not a baseless or senseless one. Minds are agents of transformation, and this is transformation of a public, shared world—that is a central theme of the book. But the mind is also the home of privacy, particularity, and the unrepeatable quirks of each person’s history and situation. Points of view are private. Thoughts are private. The world encountered and acted upon is not.
Similarly, there’s a tradition, in philosophy and elsewhere, of saying that consciousness “makes the world”—or that it makes each person’s world, as we each make our own reality. We don’t; we live in a shared reality. That reality is continually transformed and to some extent constructed by living activity, including action, and consciousness is part of that story. Rather than making our own reality, we all have a role in shaping our common reality, by means of action.
Those are all questions and themes we’ll encounter in the chapters to follow. There is more, as well—communication and culture, beauty and valuation, life and death—with some of these encountered at stages along the book’s main stem, and others coming off to the side.
Stems, branches … the metaphor is arboreal. This is also much of the setting for the book. It is a forest book, through many of its pages, though one interspersed with returns to oceans and reefs. A lot of the thinking that lies behind this book took place in those settings. The path of this book is often on land and among trees, but with forays back to the sea, where it all started.
Copyright © 2024 by Peter Godfrey-Smith
