Philosophy deals with so many difficult questions, many of them fraught with paradoxes. It's easy to think "There must be an answer. Perhaps I can figure it out." That's the hook that draws you in.
Here's an example of one coming from a very unlikely source: St. Augustine in his Confessions, Book 11. While he is mostly associated with religion, he seems to have been the first to ask a question that puzzles not just philosophers but physicists even today. The question is...
How long is the present?
A piece of paper exists because it has a thickness. If it had no thickness at all, it couldn't exist. So any piece of paper, no matter how thin, has SOME thickness even if it's the thickness of a single molecule.
The past no longer exists and the future doesn't exist yet, so the present, logically, must have some duration in order to exist at all. How long is the present?
Think about that for a while. If you're the least bit obsessive, it will bother you.
Many Eastern philosophers believe and some physicists conjecture that time is an illusion anyway. Other physicists speculate that time, all time, already exists and that the feeling we are moving through it is the illusion. If that is so, what happens to free will?
It is certainly true that our sense of time's passage is varied. When we are engrossed in what we are doing it feels as though it flies by. When we dread what we are doing it drags. And in time of crisis it feels like time freezes. And i think athletes have that sense when they are in the zone. The game slows down for them.
You aint got to sell me on free will. To my mind it is tough to even conceive what the hell it would look like. But obviously that would negate free will.
That occurred to me when i was a child. And i dont have any better approach to it now than i did then.
well maybe the issue stems from our western notion of time as linear. so maybe the past present and future are dynamic, whatever that means. or maybe it is a mistake to conceive of time as westerners do.
"How long is the present?"
The present is as long as it takes to recognize it, which takes only a moment.
I visualize Time as part of “Spacetime”. As the Universe expands more “space” is created and as we are moving through this space (inertial reference frame), we are moving through “time”. Our “Now” is constantly evolving to become a “new Now”. It is always “Now”. As we move though the curvature of Spacetime the straight line we move in gives us the sense of the “arrow of time” and of time passing (our new “nows” being created).
I imagine sitting on the arrow of time but only able to look forward. It is like surfing on a wave. With the expansion of the Universe the (electromagnetic) wave is able to continue moving forwards as it has more room to expand into. It may appear to be stretched from a different viewpoint but for us it is constant. The wave is doing the moving and we are along for the ride. From our reference point we are always in the “local” Now.
The present is as small as you can measure for practical reasons, however like a point in space, it is infinitely small. So we decide the 'unit of the present' as it applies to our space-time reference...The present decade, year or microsecond, but as that increment gets smaller the future and past become one and the same as we cease to exist and become immaterial to all other points of reference.
"How long is the present?"
I've never read of a satisfactory answer but there is: per human experience "now" is extended over multiple "nows". This for example of what's involved in the experience of hearing and labeling the word "blue" which is just one experience among countless more all within an extended (or multiple extended) nows. That's an unsatisfactory answer though still a little useful.
All that's necessary for us is to sufficiently explore neuropsychology in depth and define "human experience", "now", "extending experienced now over nows" and "nows". A trivial task no? ;)
My mind/brain is always a little behind my sense organs, so do they exist in different nows? Does every cell or even atom in my body exist in a different slice of time?
If, as Gregg proposed, the present consists of "on Planck," then is time like a movie? a series of "stills" which we perceive as analog and continuous?
That may be the only way to continue to perceive time as having duration.
I wish this moment would last forever.