We don't normally live in the present. We spend most of our time caught up in memories of the past or leaping ahead to the future full of worries and plans.
This is an illusion.
The truth of the matter is that there is no future and there is no past, but only a eternally endless Now. This Perpetual Now is all that is real and all that exists. The past and the future don't really exist in any concrete way - they're abstracts. We are always chasing the future and remembering (or forgetting) the past.
Breathing is a present-time process. It only occurs in the here and now. The breath has none of that 'other-timeness' (past, future, yesterday, tomorrow). When we truly observe the breath, we are automatically placed in the present. we are pulled out of the kaleidoscope of mental images and into the naked experience of the here-and-now. Breathing is a living slice of reality.
So, is this Perpetual Now perceivable? Is it infinitely huge in scale, or is it infinitely small and fleeting?
But here's the kicker. You are to notice them and exist within them.
Not remember them
...nor anticipate them.