I’ve contemplated this from many angles and they’re all problematic in one way or another. Asking this question is like opening up one of those toy cans of snakes where a bunch of stuff springs out and can never be put back in. Here are some of those snakes and where I think they come from.
We have two time periods the “Past” and the “Future”, and one point in time, the “Present” or “Now” to consider.
The Present seems to be an easy starting point that we can pretty much all agree on. There seems to be a physical world that indeed exists at this exact moment that we are experiencing. Whether this is true or false I can not tell you, but it seems to be a rather agreeable axiomatic starting point.
Now, the Past. Does it exist? There are two options: 1) The past exists, that is it persists and is still physically there. 2) The past does not exists; the entire universe is obliterated as every single instant we experience passes. I personally lean towards option one since option two tends to bring up more existential problems: where does it go? how does it get there? etc. Whereas if it just continues to exist, then it just is.
Now I can’t just stop there, that seems very unfulfilling. I can’t help but ask the same about the second period of time, the Future. The same options are available for it as for the Past. 1) The future already exists. 2) The future is continuously created as our perceived passage of time moves forward. Again I lean towards option one. Once more, option two just raises too many questions. How is it being created? By what? Out of what? Can a mistake be made and my kitchen table will suddenly cease to exist? All of our experience of the universe points towards something never coming from nothing (at least on the macro scale, the quantum scale has some surprising things in store for us).
But hang on just one moment. Here’s one of those snakes in a can. If the future already exists, what about my free will? Oh boy. Yup that’s a problem. Maybe it will play a role in whether you believe the Past and the Present exist or do not. Personally, given my incredulity of the idea of a new universe being created from nothing every instant, I’m forced to believe our free will is an illusion, yet, slightly ironically, we have no choice other than to live as if we have free will. Enough of that snake, toss it aside.
So that’s just space. Aren’t we leaving something out? Don’t we live in space-time? Time is our perception of the Now changing into the Future. What’s going on here? I posit four options, which are the various combinations of the Past’s existence, the Future’s existence, and our axiomatic assumption that Now exists. Two of them are silly and two reasonably follow from our previous beliefs
Interestingly, the one most people probably subscribe to is one of the silly versions (so judgmental, sheesh). The past exists but the future does not. Why do most people intuitively believe this? It maintains our free will (probably the biggest reason) and it kinda sorta helps form a framework as to why we remember the past but not the future. The problem is that it requires you to arbitrarily believe option 1) above regarding one of our periods of time and option 2) above about the other! This seems to me rather like cherry picking our beliefs to conform the universe to how we want it to be…
I imagine the inverse is obviously silly to you, the past does not exist and yet future does. That is, the Now is constantly becoming a pre-existing Future and instantly disappearing into a non-existent past. This flies in the face of our experience, yet is no less arbitrary.
So what about the other two options? If we’re consistent with our beliefs of the two periods of the Past and the Future, what about neither existing? The Now is all that exists (axiomatically), constantly being created from nothing and constantly disappearing to nothing. I can’t even fathom a mechanism for this orderly process short of introducing a mythology of some sort of creator which leads to the usual infinite regresses we’re all familiar with regarding the existence of any sort of God. Yikes! Snake-in-a-can (and one hell of a mouthful)! Toss it away! So, your belief in a creator of whatever flavor of the day it may be could influence your belief in the existence of the Past and Future.
Finally, the one that makes the most sense to me. The Past exists. The Now exists. The Future exists. It’s elegant. There’s no coming and going. There’s no leaving any creating of our orderly universe to chance or a mythological entity. It’s just all there. Always has been, always will be. It has the added bonus of neatly falling in line with our axiomatic starting point: The Now exists.
But wait! There’s a couple more damned snake in that can! I’ve managed to carve space into one giant solid block of existing Past, Present, and Future. How in the world are we moving through it? What the fuck is Time? This is the question that keeps me hot and bothered. What exactly is changing the Present into the Past and into the Future? Honestly, I don’t think anything is. I think existence is static and four dimensional, the three dimensions of space and one of time. What I want to know is what about this mass of atoms sticks me (Arrgh, Snake, what’s a person???) on this one-way path (Crap, SNAKE, the Arrow of Time!) through a never changing eternal space-time adventure.
So basically, it’s complicated. There are probably a thousand doctoral theses in each aspect we have to consider, and I’ve just given one super naive guess at it. Coming to a solid conclusion may not be within reach of human experience. In the end, it may not matter much. If the truth about it is unknowable, which I’m not convinced of, or until it is known, maybe even when it is known, we going to mold our beliefs about the truth to whatever beliefs we already hold, this I am convinced of.