The present time “does not exist.”
It isn’t even fleeting.
The past is gone and often missed,
And just keeps on retreating.
They say tomorrow never comes –
You can’t give it your greeting.
The message of this simple rhyme
Seems very, very strange,
For if there’s no such thing as time,
Then what could ever change?
(GL 2013)
We all are aware of something called time, but it is hard to define what it is. It seems to have something to do with change, or with sequences of events, but we are still aware of it when nothing seems to be happening. And we have concepts of now, and before and after, which seem to be essential aspects of time.
But what is time? Is there such a thing as the present time? Does time exist? What do philosophers and scientists think about it?
There are more philosophical opinions on this topic than there are on most other parts of the physical sciences. And scientists also disagree about some aspects of time. So this essay will be just a simple overview. And there is much more to say about time than is covered here.