There’s an argument that time is an illusion. There’s nothing but the present — the now — or, rather, an infinite number of nows. In the conventional view, one now succeeds another, which creates the illusion of the passage of time. In the view of some physicists, all nows exist at once, and we merely perceive them sequentially (or so it seems).
A problem with the conventional view is that not everyone perceives the same now, according to Einstein’s special theory of relativity. A problem with the view that all nows exist at once (known as the many-worlds view), is that it’s purely a mathematical concoction.
Oh, wait, that’s also true of the special theory of relativity, though the underpinnings of the theory have been proven experimentally. But, as I understand it, the Lorentz transformation enables one to reconcile the various nows of special relativity, that is, to stand in the place of an omniscient observer. So, in effect, there really is a now — or an infinite series of nows, perceived sequentially.
This leads to the question of what distinguishes one now from another now. The answer is change. If things didn’t change, there would be only a now, not an infinite series of them.
What happens between one now and the next now? Change, not the passage of time. What we think of as the passage of time is really an artifact of change.
Time is really nothing more than the counting of events that supposedly occur at set intervals — the “ticking” of an atomic clock, for example. I say supposedly because there’s no absolute measure of time against which one can calibrate the “ticking” of an atomic clock, or any other kind of clock. (See Einstein’s special theory of relativity.)
In summary: Clocks don’t measure time. Clocks merely change (e.g., “tick”) at supposedly regular intervals, and those intervals are used in the representation of other things, such as the speed of an automobile or the duration of a 100-yard dash.
Time is an illusion. Change is real. But change in what — of what does reality consist?
There are two basic views of reality. One of them, according to Bishop Berkeley and his followers, is that the only reality is that which goes on in one’s own mind. The other basic view, held by most people (including most scientists), is that there is an objective reality out there, beyond the confines one’s mind. How, after all, can so many people agree about the existence of certain things (e.g., Cleveland) unless there’s something out there?
Over the ages, scientists have been able to describe objective reality in ever-increasing, ever-minute detail. But what is it? What is the stuff of which it consists? No one knows or is likely ever to know. All we know is that stuff changes, and those changes give rise to what we call time.
Pardon my seriousness. Someone must have put something in my soup.