Time, space, are part of a prior organizing processes that give order to our sensations, in other words phenomena, "our world."

In talking about duration, I am not talking about time explicitly, but why duration should be as it is. Why is there a sense of different durations for different sequences of events. Why not a fixed duration (of constant value) for all events in all such sequences?

The best answer is evolution and survival. In the process of becoming awareness there is the becoming of awareness of time, a very sensible tool for survival. Duration in time of varying degrees is good for survival. Therefore it is there. (one of many answers).

Why evolution should result in awareness and its components is one of the great unanswerable questions.

But another happy choice came to me. Duration is not one of the a priori processes giving order to sensation but is a noumenal process giving representation to us, or it is both. This might imply a noumenal process also gives representation to us as time. Time then has an existence, as a representation of a noumenal process, "the real of the real."

As a representation we can be happy with it. As a noumenal process we can never know what time is.