This is the most fundamental question concerning time:

If time doesn't exist as such, if the only reality of time is to be a mere convention, a convenience to ensure the necessary synchronisation of our activities across society, including the synchronisation of our machines and of our scientific instruments, then how is it at all possible to durably synchronise different clocks, among other things? Assuming a number of clocks are set to read the same as some master clock, and assuming time doesn't exist, why would the clocks stay synchronised at all?