In hand watches we see time pass, occur, happen, elapse or become. This is the continuous succession of irreversible changes that go from the past to the future through the present. That is the first nature (N1) of time.
The second nature (N2) of time is duration, intervals, or periodic events. Duration is the interval between two sequential moments, one of which occurs before (start) and the other after (end).
In the hand watch, an interval is completed when the minute hand passes twice through the same point on the watch face. This is a periodic event. But this second nature of time is sub-perceptible because we only see one event at a time: the beginning and the end.
The movements of the Earth are the N1 of time and the day (24 hours) is the N2.
This is the enigma of revealed time, two natures: becoming and duration, which confirms the becoming-duration duality.
In summary, time is the length (N2)) flowing (N1) of phenomena Time is defined as the duration of things subject to change that determine the periods and times.
