Chapter 0 — Prologue
A flame is something happening
A candle flame looks like a thing. It has a shape — a teardrop, bright at the edges and blue at the root, narrowing to a point that wavers and recovers. It stays where it is. Blow on it gently and it bends, flickers, and settles back into the same shape, as though it remembered it. An hour from now it will still be there, the same flame by every ordinary standard, though not one particle that composes it now will be part of it then.
It is not a thing in the way the candlestick is a thing. It is something happening. Heat from the flame melts the wax at the top of the candle; the liquid wax climbs the wick, drawn up between the fibers the way water climbs a paper towel; near the flame it turns to vapor; the vapor burns, and the burning makes the heat that melts more wax. The hot gases rise, and as they rise they pull fresh air in at the base, and the fresh air feeds the burning. The teardrop is the shape of that traffic. Take away the rising and the shape goes with it: in orbit, where hot gas has no reason to rise, a candle flame is a small, dim, blue sphere. The form is made by the flow, and it lasts exactly as long as the flow does. Pinch the wick and there is nothing left to point to — no body, no remainder, only wax and a thread of smoke where the flame was.
This prologue is a story about things like the candle, told quickly and from the beginning, and it will come back to the candle at the end. It is the story the rest of the book takes for granted: how a universe with no plans came to hold structures, then selves, then selves that carry models of their surroundings and revise them. The book’s account of value begins inside this story, at the point where a structure first keeps itself going, and the patterns it traces return as the book’s account of morality. It is told as our best current sciences tell it — a map, drawn by creatures who stand somewhere, as the first chapter will insist — and where the map is blank, I will say so.
Energy runs downhill
The whole story rests on one rule: energy runs downhill.
The rule is the second law of thermodynamics, and its popular summary misleads. It is usually remembered as a tendency toward disorder, as though the universe were slowly coming apart and anything organized were a temporary exception to the trend. Stated with care, it says something plainer. For any rough description of a system — its temperature, its pressure, where its boundaries lie — some number of microscopic arrangements fit the description. Left to itself, a system drifts to the descriptions that more arrangements fit, for the simple reason that there are more of them. Entropy is the measure of that count. Nothing in this is hostile to structure. A structure is a constraint: fewer arrangements fit it than fit the featureless alternative. Some structures, a crystal of ice or a rock, settle into such a constraint and then need nothing further; they last because nothing pushes them out of it. This story follows the other kind: structures held away from that resting state, which form and last only so long as the count rises by more somewhere else — so long as energy flows in, through, and out the other side.
The early universe was nearly smooth: a hot, almost uniform gas, very slightly denser in some places than in others. Gravity worked on the differences. Denser regions drew in more gas and grew denser still, and within a few hundred million years some of them had collapsed far enough to ignite. The first stars were the first great gradients — concentrated heat pouring into cold space — and they were also the first forges. In their cores hydrogen fused into helium, helium into carbon and oxygen, and in the most massive stars on up to iron; those stars ended in explosions that scattered what they had made into the gas from which later stars, and their planets, would form. Every atom of carbon in the candle, and in the hand that lit it, was made that way.
Where energy flows through matter, structures appear that carry the flow. A pan of oil heated from below shows it in miniature. Below a certain rate of heating nothing visible happens; heat moves upward by conduction, molecule to molecule, and the oil stays featureless. Past that threshold the oil organizes itself into a mosaic of rolling cells, each carrying warm oil up its center and cool oil down its sides. No one arranged the cells. The gradient permitted them, and once formed they held. Heat the pan much harder and the neat cells break up into churning turbulence — a great deal of motion and no lasting shape. Too little flow and nothing forms; too much and nothing holds. The cells live in between.
The weather is the same thing at the scale of a planet. Sunlight warms the equator more than the poles, and the difference drives the circulation of the atmosphere — the trade winds, the jet streams, and the storms that form, travel, turn for days, and come apart when they leave the warm water that fed them. A hurricane is a candle the size of a country.
None of these structures has an inside. A convection cell keeps nothing out; a storm maintains no boundary between itself and the air it is made of; nothing is at stake for either. This is pattern with no self. It is easy to pass over, and a mistake to. Everything that follows is built on it, and the structures that follow never stop being, among other things, flows that make forms.
What is left
Structures come and go. Which of them are still around later is settled by something simpler than it is usually made to sound.
Nothing chooses. Things that cannot continue stop, and what we find afterward is whatever did not stop. There is no aim in this and no guarantee — only removal, repeated without end. Whatever looks designed in the result is the outline of what was taken away.
The removal works from two sides, and the candle already shows both. Close the flame off — set a glass over it — and it uses up the air inside and goes out. Open it too wide — stand it in a draft — and the wind pulls the burning apart faster than it can renew itself, and it goes out. The flame continues only in between: open enough to draw in what it needs, held together enough to stay one flame. The oil showed the same two failures, and so, in its own material, will everything later in this story. A structure sealed off from exchange cannot change when its surroundings change, and surroundings always change eventually. A structure that cannot hold itself together against exchange does not last long enough to be anything at all. What persists lives between the two.
The space between is not a line but a range, and the things that last longest tend to be the ones that can shift their own position within it — opening a little when that serves, closing a little when that serves.
Pieces into wholes
The second thing that happens, given time, is combination.
Lasting pieces join into larger wholes, and the wholes can do what no piece can. Protons and neutrons bind into nuclei; nuclei gather electrons and become atoms; atoms share electrons and become molecules. A molecule of water has properties that neither hydrogen nor oxygen gives any hint of — what is usually called emergence. At each step the parts remain inside the whole, still themselves, and the whole becomes a new kind of part for the next step.
On the young Earth — wet, warm, washed in sunlight and in the chemical energy of volcanic vents — molecules combined and recombined in enormous variety. Some combinations broke apart quickly. Some lasted. Some, by the chance of their chemistry, helped make more of themselves, or more of what they were made from. How this led to the first living thing, nobody knows. There are serious hypotheses — about self-copying molecules, about chemical cycles on mineral surfaces, about bubbles of fatty molecules that form and divide on their own — and none has yet been shown to run all the way from chemistry to a cell. It is the largest blank on the map, and it should be marked as one. What is not in doubt is that by about three and a half billion years ago, and probably earlier, there were cells.
A cell keeps itself going
A cell is not a flame, and the difference between them is the most important fact in this story.
The flame, as we saw, sustains itself. It draws in fuel, makes the heat that keeps it burning, and recovers after a puff of air. But it keeps nothing. It has no edge of its own; it is wherever the burning happens to be. A cell has an edge, and it makes the edge itself: a membrane, built and repaired by the chemistry inside it, that lets some molecules through and keeps others out. Within that membrane the cell holds its chemistry inside the narrow range in which it can go on, rebuilding its own parts from what it takes in. The flame is kept going by the flow. The cell keeps itself going. That difference is enough to put something new into the world: for the first time there is something for which things can go well or badly — something with a stake in its own continuance. What that stake amounts to, and why it is the beginning of value, is the first chapter’s business. Here it is enough to see where it appears: not as an addition from outside, but as a change in how a flow is organized.
The membrane is the space between the two walls, made into an object. Sealed, a cell starves; opened, it spills. A membrane whose channels open and close is a cell that can move its own position within the range.
The cell does one thing more. A swimming bacterium compares the chemistry around it now with the chemistry of a few seconds ago. If the nutrient is richer, it keeps swimming; if poorer, it tumbles and sets off in a new direction. That comparison is a model — the barest possible one, a few seconds of chemical memory standing for more food this way than that — and the world corrects it constantly. It is the first instance in this story of a structure that carries a model of its surroundings and revises it on contact with what it meets.
Its genes are a slower model of the same kind. A genome is a record of what worked for the cell’s ancestors — which proteins, which responses, which ways of being built — and it is revised the way everything in this story is revised: copies that worked poorly leave fewer copies. The revision takes generations. It is exact about the past and blind about the future.
Wholes made of wholes
For something like a billion and a half years, cells stayed small and simple. Then one cell took in another and did not digest it.
The engulfed cell, a bacterium that could draw energy from oxygen, went on living inside its host and dividing when the host divided. Over a very long time the two became one: the guest became the mitochondrion, and the host the ancestor of every animal, plant, and fungus. The mitochondria in your cells still carry a small genome of their own, left over from the free-living bacterium they descend from. It is the clearest case we have of a whole made of wholes: two lineages, each able to continue alone, combined into something that could do what neither could, each still recognizably present inside it.
The same move happened again at larger scales. Cells joined into bodies — many separate times — and divided the work among them: some to carry signals, some to digest, some to reproduce for all the rest. Bodies joined into colonies, as in the ant nest and the beehive, where the colony behaves in some respects as a single organism. The biologists who cataloged these major transitions found that each had the same structure: units that had once copied themselves independently came to copy themselves only as part of a larger whole.
Each such level reaches farther. A bacterium meets the world a few thousandths of a millimeter at a time, over seconds. A tree meets it across meters of air and soil and over centuries. An animal with eyes meets it at a distance, before it arrives. Each new level of organization comes into contact with more of the world — more kinds of things, from farther away, over longer stretches of time — and that means more possibilities and more exposure. The space between the walls changes with it. A single cell has few ways of being viable. A body built of tissues and organs, each with its own partial closure — skin, gut lining, the barrier around the brain — has many more, because it can be open in one place and closed in another. The range of what can last widens as organization deepens: not with size, but with nested, differentiated structure, parts within parts within parts. The two walls are present at every level. An immune system must attack what is foreign without attacking what is self; it fails in one direction as immunodeficiency and in the other as autoimmunity. A nervous system must be excitable enough to carry a signal and damped enough not to seize. A breeding population needs enough exchange with its neighbors to keep its variation, and not so much that its fit to its own place washes out. These are not separate corridors to be passed one at a time. A living thing has to stay within many such ranges at once — heat, salt, acidity, exchange and more — and what can last is the region where every one of them allows it.
Faster models
Nervous systems sped up the modeling.
A genome learns over generations. Learning within a single life began without nerves — a slime mold, one sprawling cell, keeps a record of where it found food in the widths of its own tubes — but a nervous system made it fast: some of what it learns, it learns in seconds. An animal with a brain carries a running model of its surroundings — what is where, what is about to happen, what has gone well and badly before — and checks the model against its senses continuously, adjusting it when the world returns something it did not expect. An animal that has once been stung keeps clear of the thing that stung it. A crow learns which people are dangerous, and other crows learn it from the first. The time between a mistake and its correction, which for genes was a generation, became for brains a moment.
Then a particular primate — already social, already a maker of tools — began to share its models by speaking. Language let a model built in one head be revised by what had happened to someone else, someone far away or long dead. Writing, a little more than five thousand years ago, let models outlast the people who held them and accumulate across generations faster than genes could carry anything. Cities formed, which are flows that make forms on a new scale: grain, water, goods, and people moving through streets laid down by their own traffic, the city lasting only while the movement goes on. Institutions formed — wholes made of people — with the same two failures open to them as to any membrane: some close themselves off and cannot learn, and fall when the world changes; others cannot hold together, and come apart. Science formed: a deliberate practice of exposing models to contact with the world so that the world could correct them faster than it otherwise would.
Each new medium revised its models faster than the last — generations, then lifetimes, then seconds, then cultures that change within a single life. And now machines. In the last few years, systems built from silicon and trained on the written record of human beings have begun to carry models of their own, revised far faster than any genome, consulted by millions of people at once, and combined with human work in arrangements nobody yet has good names for. The networks that carry them are flows that make forms too: information moving through them shapes the channels it moves through. Whatever these systems turn out to be, they are the newest place where the same processes are at work, and they are at work there faster than they have been anywhere.
The candle on the windowsill
The candle is still burning.
It is the same kind of thing it was at the start: a form made by a flow, lasting only between too little air and too much. It has no inside and keeps nothing, and the story told here has been, in one sense, a list of the things it cannot do.
This one stands on the windowsill of an animal shelter, near closing time. Abel is waiting beside it with a book, having come to walk Tara to her car. Tara is down the row of crates, finishing up, and asks her phone whether it will rain tomorrow. It tells her. Someone lets the front door swing shut on the way out, and the flame leans, flickers, and stands back up. They will be back tomorrow too.
Nothing in what you have just read says what either of them should do tomorrow. The universe in this story has no plans, and its laws, however exact, say what happens, not what anyone should do. What persists is not, by that fact, good: a thing can keep itself going very well and still be a narrow and closed thing, and the most elaborate structures are not, for being elaborate, the best. All the story can say is where they came from and what they are made of — and that the patterns that made the flame, the cell, the body, and the city are at work in that room, in the work each of them will go back to in the morning, in the institutions around them, and in the phone in Tara’s hand, where they now run fastest of all.
Some ways of continuing take in more of the world than others. Whether that has anything to do with better, and where better comes from at all, is not a question the universe asks. It took something like Abel and Tara to ask it. The rest of this book is their question, and the patterns in this prologue will return in it.