What is a moment?

[BadgerJelly]

How can a moment exist for us as humans in physical reality?

What is the smallest unit of "time"?

More to the point - What are the implications of your answers to these questions in terms of Physics, neurology and the nature of the universe?

[neuro]

How can a moment exist for us as humans in physical reality?

What is the smallest unit of "time"?

More to the point - What are the implications of your answers to these questions in terms of Physics, neurology and the nature of the universe?

Contrary to theoretical philosophical discussions on the possibility/impossibility of the "present moment", the neurological perspective solves many contradictions:

1) most sensory systems display adaptation, which means that their momentary discharge partly relates to the momentary stimulus, partly relates to the way the stimulus is changing (and therefore the past)

2) all neuronal circuits introduce variable delays in parallel processing of the same information, in such a way that the momentary activity of a neuronal circuit always combines "the present" and "the past", i.e. the brain is constantly processing momentary information together with the way such information is changing in time

3) as a consequence of the above, the brain elaborates change with time with the same efficiency with which it elaborates current information, so that the "neurological moment" simultaneously is a representation of the actual moment, past events and the way things change out of and within ourselves

As regards the "smallest unit of time", that depends on what you are interested in. Whatever event or process you are studying, it makes no sense to try and describe it over time intervals smaller than an appropriate time-scale (for example, in neuronal processes a time-scale below 1 ms does not make sense, because the neuron would not "feel the difference", whereas for mental processes some hundred milliseconds seem to consitute the minimum significant delay).

In theory one can arbitrarily reduce the time scale, to better qualify "a moment", and get to infinitesimal calculus and Dirac's delta functions which are quite useful instruments; in physics, I would suggest that the "smallest unit of time" might be that which brings you from being better able to precisely define the speed than the position of a particle (because the observation time is too long) to being better able to define its position than its speed (because the time interval is too short). Possibly, some physicist here may say what such a time unit would be...