On Becoming, and Why the River Is Not a Metaphor.

Heraclitus is supposed to have said that one cannot step into the same river twice. The line has travelled so widely, and been quoted so affectionately, that almost no one any longer notices what it is doing. It is offered, in the ordinary telling, as a small poetry about the passage of time — the water moves, we age, nothing stays. It is not that. Or rather, it is that, but only in the same way that Being and Time is a book about alarm clocks.

To see what is actually being said we have to hold the image still for a moment. The river, Heraclitus says, is not the same. Very well — what makes a river be a river, then, if its water is not what makes it one? The ordinary answer would be: its banks, its bed, its route through the country. Those parts are stable; the water through them is not. On this reading, the sentence is a species-level truism — a thing's substance holds while its accidents change — and it deserves the mild philosophical reputation it has acquired1The survey histories take this reading almost without argument. See Guthrie, A History of Greek Philosophy, vol. I, for the version that became standard in twentieth-century English scholarship..

But this is not, in fact, what Heraclitus says. He does not say the banks are the same and the water is not. He says the river is not the same. And then he says something harder still, which we usually drop: we are and are not. The subject of the sentence is not the landscape; it is us, and we are in the same trouble as the river.

Into the same rivers we step and do not step; we are and are not.

Heraclitus · DK 22 B49a

What he is saying, if we allow him his strangeness, is this: the river is not something that has water running through it. The river is the running. Take away the running and there is no river — there is a shape in the mud, a dry bed, an old path. The thing called river is not the mud and is not the water; it is an ongoing activity of which those happen to be parts. The river is not a thing that is flowing. The river is the flowing itself.

This is a very different claim. It says that for at least some of the things we point at in the world, what they are is an activity, not a stuff. You cannot point to the river at an instant and find the river, because the river at an instant is not yet a river. It is a cross-section of a running. A thing which has to be, in order to be, is a new kind of thing in philosophy — strange in Heraclitus's time, a little less strange by Aristotle's, and oddly familiar in ours.

The second river

Here is where the sentence catches us. Heraclitus does not stop with the river. He says that we are and are not. We are in the same condition as the thing we were using as an example. This is the harder part of the fragment, and it is the part that the survey histories skip over most cleanly.

What would it mean for a person to be an activity rather than a stuff? The medievals, later, would put it this way: we are alive, and to be alive is not the same as to exist. A stone exists. A person is alive — which is to say, is something that is continuously happening. If the happening stops, we do not have a person who has stopped; we have a body, which is a different kind of thing. The identity condition of a person is not satisfied by the parts being present. It is satisfied by an activity continuing.

Heraclitus is already here, half a millennium earlier. "We are and are not" is not a paradox in search of an ingenious reading. It is a flat statement that the reader is, like the river, the running through a shape. The shape holds; the running constitutes it.

Aristotle's answer that nobody asked

Aristotle did not think of himself as answering Heraclitus when he formulated the doctrine of form and matter. By the time he was writing, Heraclitus had been frozen into a doxographical footnote, a handful of riddles about the logos and the fire and the bow. Aristotle's categories are, officially, after Plato — they are a response to the separability of Platonic forms, not to pre-Socratic flux.

And yet. Read the De Anima with Heraclitus in the other hand. Aristotle says the soul is the form of a living body2See De Anima II.1, 412a27–b1: "the soul is the first actuality of a natural body which has life potentially.". He is very careful to say the soul is not a part of the body — it is the body's being alive, its doing of the kind of thing it does. A soul detached from a body is as coherent a notion as a river detached from its flowing.

This is Heraclitus, given technical terms. What was, in the Ephesian, a paradox — we are and are not — becomes, in Aristotle, a distinction: we are the form of the matter we happen to be made of, and the form is not the matter. The form is us; the matter is what we are doing when we are alive. Take the activity away and you are left with, at best, a body — the thing the Greeks called a nekros, a corpse. Which is, as they say, not a kind of person but a kind of thing that used to be one.

Why this matters for reading

A page, like a person, is a form imposed on a matter. The matter is the ink, the paper, the pixels, the screen; the form is the arrangement, the measure, the chosen face, the pauses between paragraphs. When you set aside a book you loved and pick up another that is set in the same typeface at the same measure, you feel, before you have read a sentence, whether you are in the same room or a different one. What you are feeling is the form — the activity of this page being the page it wants to be.

Bad typography is not an absence of care. It is a disagreement between the matter and the form — a running that does not shape anything, a shape that nothing is running through. What a reading-first design system is for is the opposite: to keep the shape and the running in one argument. To make the page a river, not a rut.

Heraclitus would have recognised the problem, I think. And Aristotle would have given us the word for the solution.