my question is about the nature of time across classical/macro and quantum scales. I understand that the 2nd law of thermodynamics and entropy increase has a lot to do with our understanding of time and what it is in classical physics; manifested in the irreversibility of certain physical processes, linear cause and effect etc.
However, I have been reading about the difficulties in determining the nature of time in particular at the quantum level. I have read it variously stated that quantum mechanics is time symmetric, that time evolves from thermodynamics only at the macro-scale and that in effect, time is not perceived at the quantum level.
I understand that energy dissipation itself, and therefore entropy may not be conceived in the same way as it is on macro scales, but the probabilistic nature of quantum events surely meets the definition of irreversibility. i.e.: even taking all output parameters from an event and running the event in reverse there is only a probability of the initial state arising, not a certainty. Therefore cause and effect, are also linear at the quantum scale. Indeed due to this probability element, there is no way to accurately reverse events.
Is there not a correlation between this underlying objective indeterminism of quantum mechanics and the fact that time exists at all? If quantum mechanics were deterministic and not based on probability then I DO see an issue in that events would in fact be reversible. Otherwise I don't see any time symmetry problem... am I mistaken?
Sorry if this has been asked before; I couldn't see anything precisely of this nature but perhaps that is a result from my poor comprehension of some of the more technical question formulations.