"Hope, you see, Wal'r," said the Captain, sagely, "Hope. It's that as animates you. Hope is a buoy, for which you overhaul your Little Warbler, sentimental diwision, but Lord, my lad, like any other buoy, it only floats; it can't be steered nowhere. Along with the figure-head of Hope,' said the Captain, 'there's a anchor; but what's the good of my having a anchor, if I can't find no bottom to let it go in?"
Living in the moment means letting go of the past and not waiting for the future. It means living your life consciously, aware that each moment you breathe is a gift.
It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure.