"Yesterday is history, tomorrow is a mystery, but today - it's a gift, that's why it's called present"

As said by Oogway to Po

An interesting thought! We are in general so obsessed with past and future that we rarely take time and live the present. All our sense of self is derived from our knowledge of past and memories that we have acquired over the years. We identify and restrict ourselves based on these memories.

We have different kinds of epistemic access to past and future. We remember the past, but not the future. We also believe that by acting now, we can change the future but not the past. Why are things like this has always been a mystery for me. Science doesn't have any clue either, neither is religion really clear about it. But, what about present!

The principle of duality, if correct, predicts that there is only past and future. That may imply that there's no such thing as present. What we perceive as present is a fuzzy area where past and future meet. Contrary to a popular perception that present is a thin infinitesimal line dividing the past and future, it's rather like a band. The width of this band differs from person to person and depends upon how acute somebody's perception is.

But analysis besides, I think the present is the only thing that we really have. Past exists only in the memories, and future is unknown. We are creatures of our sense organs. And all our senses function only in the present. We are what we are now, not what we were or what we will be.