The Order of Time

by Carlo Rovelli

If we could measure the duration of an interval with the most precise clock imaginable, we should find that the time measured takes only certain discrete, special values. 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.

To ask oneself in general “what exists” or “what is real” means only to ask how you would like to use a verb and an adjective.64 It’s a grammatical question, not a question about nature.

We are the ones who determine a particular macroscopic description. The initial low entropy of the universe, and hence the arrow of time, may be more down to us than to the universe itself.

We are histories of ourselves, narratives.

The directionality of time is therefore real but perspectival