Spacetime is a physical object like an electron. It, too, fluctuates. It, too, can be in a “superposition” of different configurations. The illustration of stretched time at the end of chapter 4, for example—if we take quantum mechanics into account—should be imagined as a blurred superposition of different spacetimes, more or less as shown below.
Similarly, the structure of light cones fluctuates at all points that distinguish among past, present, and future.
Even the distinction between present, past, and future thus becomes fluctuating, indeterminate. Just as a particle may be diffused in space, so, too, the differences between past and future may fluctuate: an event may be both before and after another one.
RELATIONS
“Fluctuation” does not mean that what happens is never determined. It means that it is determined only at certain moments, and in an unpredictable way. Indeterminacy is resolved when a quantity interacts with something else.*
In the interaction, an electron materializes at a certain point. For example, it collides with a screen, is captured by a particle detector, or collides with a photon—thus acquiring a concrete position.
But there is a strange aspect to this materialization of the electron: the electron is concrete only in relation to the other physical objects it is interacting with.56 With regard to all the others, the effect of the interaction is only to spread the contagion of indeterminacy. Concreteness occurs only in relation to a physical system: this, I believe, is the most radical discovery made by quantum mechanics.*
When an electron collides with an object—the screen of an old television set with a cathode ray tube, for example—the cloud of probability with which we conceived of it “collapses” and the electron materializes at a point on the screen, producing one of the luminous dots that goes into the making of a TV image. But it is only in relation to the screen that this happens. In relation to another object, the electron and screen are now together in a superposition of configurations, and it is only at the moment of further interaction with a third object that their shared cloud of probability “collapses” and materializes in a particular configuration—and so on.
It is hard to take in the idea that an electron behaves in such a bizarre way. It is even more difficult to digest that this is also the way time and space behave. And yet, according to all the evidence, this is the way the quantum world works: the world that we inhabit.
The physical substratum that determines duration and physical intervals—the gravitational field—does not only have a dynamic influenced by masses; it is also a quantum entity that does not have determined values until it interacts with something else. When it does, the durations are granular and determinate only for that something with which it interacts; they remain indeterminate for the rest of the universe.
Time has loosened into a network of relations that no longer holds together as a coherent canvas. The picture of spacetimes (in the plural) fluctuating, superimposed one above the other, materializing at certain times with respect to particular objects, provides us with a very vague vision. But it is the best that we have for the fine granularity of the world. We are peering into the world of quantum gravity.
—
Let me reprise the long dive into the depths made in the first part of this book. There is no single time: there is a different duration for every trajectory; and time passes at different rhythms according to place and according to speed. It is not directionaclass="underline" the difference between past and future does not exist in the elementary equations of the world; its orientation is merely a contingent aspect that appears when we look at things and neglect the details. In this blurred view, the past of the universe was in a curiously “particular” state. The notion of the “present” does not work: in the vast universe there is nothing that we can reasonably call “present.” The substratum that determines the duration of time is not an independent entity, different from the others that make up the world; it is an aspect of a dynamic field. It jumps, fluctuates, materializes only by interacting, and is not to be found beneath a minimum scale. . . . So, after all this, what is left of time?
You got to deep-six your wristwatch, you got to try and understand,
The time it seems to capture is just the movement of its hands . . . 57
Let’s enter the world without time.
PART II THE WORLD WITHOUT TIME
6 THE WORLD IS MADE OF EVENTS, NOT THINGS
O gentlemen, the time of life is short . . .
And if we live, we live to tread on kings.
Shakespeare, Henry IV, Part I (act 5, scene 2)
When Robespierre freed France from monarchy, Europe’s ancien régime feared that the end of civilization itself was nigh. When the young seek to liberate themselves from an old order of things, the old are afraid that all will founder. But Europe was able to survive perfectly well, even without the king of France. The world will go on turning, even without King Time.
There is, nevertheless, an aspect of time that has survived the demolition inflicted on it by nineteenth- and twentieth-century physics. Divested of the trappings with which Newtonian theory had draped it, and to which we had become so accustomed, it now shines out with greater clarity: the world is nothing but change.
None of the pieces that time has lost (singularity, direction, independence, the present, continuity) puts into question the fact that the world is a network of events. On the one hand, there was time, with its many determinations; on the other, the simple fact that nothing is: things happen.
The absence of the quantity “time” in the fundamental equations does not imply a world that is frozen and immobile. On the contrary, it implies a world in which change is ubiquitous, without being ordered by Father Time; without innumerable events being necessarily distributed in good order, or along the single Newtonian time line, or according to Einstein’s elegant geometry. The events of the world do not form an orderly queue, like the English. They crowd around chaotically, like Italians.
They are events, indeed: change, happening. This happening is diffuse, scattered, disorderly. But it is happening; it is not stasis. Clocks that run at different speeds do not mark a single time, but the hands on each clock change in relation to the others. The fundamental equations do not include a time variable, but they do include variables that change in relation to each other. Time, as Aristotle suggested, is the measure of change; different variables can be chosen to measure that change, and none of these has all the characteristics of time as we experience it. But this does not alter the fact that the world is in a ceaseless process of change.
The entire evolution of science would suggest that the best grammar for thinking about the world is that of change, not of permanence. Not of being, but of becoming.
We can think of the world as made up of things. Of substances. Of entities. Of something that is. Or we can think of it as made up of events. Of happenings. Of processes. Of something that occurs. Something that does not last, and that undergoes continual transformation, that is not permanent in time. The destruction of the notion of time in fundamental physics is the crumbling of the first of these two perspectives, not of the second. It is the realization of the ubiquity of impermanence, not of stasis in a motionless time.