Like as the waves make towards the pebbl'd shore,
So do our minutes hasten to their end;
Each changing place with that which goes before,
In sequent toil all forwards do contend.

Nativity, once in the main of light,
Crawls to maturity, wherewith being crown'd,
Crooked eclipses 'gainst his glory fight,
And Time that gave doth now his gift confound.

Time doth transfix the flourish set on youth
And delves the parallels in beauty's brow,
Feeds on the rarities of nature's truth,
And nothing stands but for his scythe to mow:

And yet to times in hope my verse shall stand,
Praising thy worth, despite his cruel hand.

- William Shakespeare, Sonnet 60

Common sense says - Time flows. But does it really flow? Its such a common expression in any language, like in poem above - our minutes hasten to their end. It conveys the message that we are standing fixed as rock in the river, and time like water is running. The coming water is the future, and the one that has gone is the past.

There are some flaws & irregularities in this common perception of the flow of time.

First, if the past is the time that has 'gone' and the future is the time yet to 'come,' then how long is the present? Is it one day long? One hour? One minute? One second? Or even smaller, because technically, the last nanosecond should be past.

Second, the 'flow' of time gives it a direction in our minds, as if time is flowing from left to right.

This is perhaps surprising. We have become used to modifying our common sense to conform to scientific discoveries. Common sense frequently turns out to be false, even badly false. But it is unusual for common sense to be nonsense in a matter of everyday experience. Yet that is what has happened here.

-Deutsch, David, The Fabric of Reality: Towards a Theory of Everything

Seeing time as a line, with the past on the left and the future on the right, is such a common mental model when we think of the 'passing' of time. Time has no direction.

After reading few books on this I understood that the image of time which I grew up with is not real. But what is real is yet to be learned in this quest of logic.

What then is time? If no one asks me, I know; if I wish to explain it to one who asks, I know not.

-St Augustine, (Confessions)