The Order of Time

The world is not a collection of things, it is a collection of events.

Why, to us, is the past so different from the future? Nineteenth- and twentieth-century physics engaged with these questions and ran into something unexpected and disconcerting—much more so than the relatively marginal fact that time passes at different speeds in different places. The difference between past and future, between cause and effect, be

Continuity is only a mathematical technique for approximating very finely grained things. The world is subtly discrete, not continuous. The good Lord has not drawn the world with continuous lines: with a light hand, he has sketched it in dots, like the painter Georges Seurat.

The growth of entropy is nothing other than the ubiquitous and familiar natural increase of disorder.

It is not possible to think of duration as continuous. We must think of it as discontinuous: not as something that flows uniformly but as something that in a certain sense jumps, kangaroo-like, from one value to another.

There is no special moment on Proxima b that corresponds to what constitutes the present here and now.

Our fear of death seems to me to be an error of evolution. Many animals react instinctively with terror and flight at the approach of a predator. It is a healthy reaction, one that allows them to escape from danger. But it’s a terror that lasts an instant, not something that remains with them constantly.

I watch a film that shows a ball rolling, I cannot tell if the film is being projected correctly or in reverse. But if the ball stops, I know that it is being run properly; run backward, it would show an implausible event: a ball starting to move by itself. The ball’s slowing down and coming to rest are due to friction, and friction produces heat.

The difference between past and future, between cause and effect, between memory and hope, between regret and intention . . . in the elementary laws that describe the mechanisms of the world, there is no such difference.