Time for a physicist is quite likely to be reversible. It doesn’t matter whether you read an equation forwards or backwards—unlike a sentence. On the subatomic level directionality is altogether lost. You cannot write the history of a photon; narration is irrelevant; all you can say of it is that it might be, or, otherwise stated, if you can say where it is you can’t say when and if you can say when it is you can’t say where.
