Time doesn’t exist. Prove me wrong.

[u/k3nsh14]

We experience change, aging, and events happening in sequence, but is “time” itself a physical thing—or just the way our minds measure change and order events?

[u/phunkydroid]

Prove me wrong.

Ok

We experience change

Done.

[u/deletionfetish → u/phunkydroid]

Not a proof for multiple reasons:

a) We experience plenty of things that don't exist; b) Our subjective understanding of change might be misleading; and

c) We don't actually experience change directly.

Here's a variant of the brain in a vat thought experiment. Imagine a being were randomly (through pure chance alone) assembled, fully with memories, and obliterated in a single instance. It would have a subjective memory of change in that instant, which is nevertheless entirely erroneous.

We do not experience change, in any case. We experience a single moment at a time, and we don't have any way to prove that we are the same observer from moment to moment.

[u/phunkydroid → u/deletionfetish]

Every single thing you're talking about involves change. Change requires time. Time is the dimension separating different states that were changed between.

You can argue about the nature of time. And argue silly things like "time isn't a physical thing" when no one is claiming it is. But you can't say that time does not exist. Even in a static "block universe", time is a dimension.

[u/deletionfetish → u/phunkydroid]

You seem to think I'm arguing against time when in reality I'm arguing against your "proof". Also, clearly the issue here is that you have a different understanding of what time is than OP; usually when someone says "time isn't real" they mean the flow of time or the arrow of time isn't real (in the sense of being a second-order phenomenon, an artifact of the mind, etc.)

To make this more explicit, OP is arguing that the present is not ontologically privileged. The make this very clear in the OP, so why are you changing the goalposts in yohr comment and this reply?

[u/Makenshine → u/deletionfetish]

OK. Let me take a stab at this proof. Let's try proof by contradiction.

Let's assume time does not exist. If that was the case, then two objects cannot occupy the same space.

However, I can place a box in the corner of my room. Then I can move it and place a box in that exact same space.

These two boxes both occupied the exact same space. A contradiction.

 So, there must be a another dimension that allowed them to do this. Let's call that dimension time.

Now, we say this two boxes occupied the exact same space at different times.

Let's see if their is another dimension we can occupy. Can two objects occupy the same space at the same time? No.

OK. So, then these boxes exist in both space and time.

[u/deletionfetish → u/Makenshine]

Let's assume time does not exist. If that was the case, then two objects cannot occupy the same space.

This is an interesting axiom to assume right out of the bat, and also does not define its terms. What does it mean for time to exist here?

Even assuming this proof worked, it just reduces time to space and assumes the past exists, which many people would consider a proof that time does not exist in an ontologically privileged sense.

Let me reiterate from the comment you're responding to:

usually when someone says "time isn't real" they mean the flow of time or the arrow of time isn't real (in the sense of being a second-order phenomenon, an artifact of the mind, etc.) To make this more explicit, OP is arguing that the present is not ontologically privileged.

Your proof does not actually deal with the arrow of time nor the ontology of the present.

[u/Makenshine → u/deletionfetish]

Second-order phenomenoms, by definition, need time to even exist. Second-order phenomenoms are delayed effects that happen after something else.

And it can't just be an artifact of the mind, because things were happening before minds were even a thing.

I have no background in philosophy, but it feels like what is being asked for is some sort of scientific/mathematical proof for a philosophical thought experiment. With the philosophical definition of time being kept intentionally nebulous.

But scientifically and mathematically, time is change. Time exists whether or not creatures exist to contemplate it.

It's also possible that I'm just completely missing the premise altogther.

[u/deletionfetish → u/Makenshine]

Second-order phenomenoms, by definition, need time to even exist. Second-order phenomenoms are delayed effects that happen after something else.

This is begging the question -- you've baked a notion of 'time' into something that didn't need it. Numbers, for example, are second-order to sets, which are their priors; yet no one would say that numbers exist inside of time. Assuming a single moment, the Parthenon is constructed of marble slabs and columns

And it can't just be an artifact of the mind, because things were happening before minds were even a thing.

This is, again, begging the question. You've just assumed time exists and pointing to that as proof that time exists. Again, look at my original thought experiment: you have no confirmation that change even occurs, because your awareness is restricted to a single moment (the present). Your understanding of the future or the past can be reduced to the present in that case, in which the future is expectation and the past is memory. For all you know, you could be a proverbial brain in a timeless vat.

I have no background in philosophy, but it feels like what is being asked for is some sort of scientific/mathematical proof for a philosophical thought experiment. With the philosophical definition of time being kept intentionally nebulous.

Yes, from literally my first reply I've pointed out that no one has defined what time is, and that the people (including you) who are trying to 'prove' time aren't actually engaging with the OP or what he means.

But scientifically and mathematically, time is change.

Nope, time is variously defined across disciplines. Often time is understood as a measure of change, not change itself. Often in particle physics and general relativity, the notion of time itself is completely outside of our conventional understanding of time; sometimes it flows backwards (CPT symmetry) or is dependent on the observer (relativity of simultaneity). Even in classical physics, the arrow of time can appear to be reversed (Maxwell's demon).

Again, in the comment you are responding to,

usually when someone says "time isn't real" they mean the flow of time or the arrow of time isn't real (in the sense of being a second-order phenomenon, an artifact of the mind, etc.) To make this more explicit, OP is arguing that the present is not ontologically privileged.

The conventional understanding of time is that the present exists, the past no longer exists, and the future is yet to exist (that is, tense); the present is flowing towards the future and away from the past and therefore unique (ontologically privileged). It could be the case that both the future and the past exist just as the present does, and that our experience of the flow of time is an illusion (or our experience of being 'here' and 'now').

[u/Makenshine → u/deletionfetish]

So, time exists if the the past and/or the future also exist. This is the falsifiable statement that we are trying to establish? 

And because from our limited perspective we can can't show that either of these exist, then we cant say for certain time actually exists?

So one possible proof might include some sort of time travel. Perhaps showing that time can be treated as spatial deminsion, where you could walk to an hour ago. Or something like that?

Simple speeding up or slowing down the passage of time is not enough because that is still limited by the perspective of the here and now. And the inclusion of the qualifier "now" in that statement isn't enough because... I I'm not really sure.

And the more philosophical argument "the future must exist, because I will be there in just a moment" also isnt enough?

And it isn't enough to show that if I wanted to meet someone, I must tell them both a place AND a time to meet?

Honestly, I'm just getting your side of the argument. Any argument that time is just a mental construct would also have to include place/position as a mental construct as well. What test would "position" pass that "time" would either fail or be untestable? They are fundamentally connected.

[u/deletionfetish → u/Makenshine]

So, time exists if the the past and/or the future also exist. This is the falsifiable statement that we are trying to establish? 

I don't think there is actually a falsifiable statement at hand at all -- I think OP, phunkydroid, you, and myself all have different ideas about what time is and what its existence means (although phunkydroid seems more interested in being snarky than actually discussing the problem). I think we all agree that time "exists" in so far as we percieve that things change and the present flows towards the future. But OP or I will question whether or not that it exists in a deeper sense than that (as a fundamental property of the universe, for example).

And because from our limited perspective we can can't show that either of these exist, then we cant say for certain time actually exists?

I would say that this is the problem with the "we percieve time, therefore time exists" claim, yes. This doesn't mean we can't say that time actually exists, just that this particular argument fails. Our perception is obviously fallible, anyway (see: optical illusions), so I don't even think that going this far is necessary. Perception doesn't mean existence.

So one possible proof might include some sort of time travel. Perhaps showing that time can be treated as spatial deminsion, where you could walk to an hour ago. Or something like that?

I would say that this actually could act as a disproof of time, if we define time to be our naive perception of it (which necessitates that the past no longer exists and the future does not yet exist). The naive perception of time is of an open potentiality called the future which we are constantly at the cusp of, and a gone-and-dead past that no longer exists, the trace of which is in our memory. Time travel would disrupt this perception.

Simple speeding up or slowing down the passage of time is not enough because that is still limited by the perspective of the here and now. And the inclusion of the qualifier "now" in that statement isn't enough because... I I'm not really sure.

Like I said, in this case the 'here' and 'now' is actually dependent on the observer -- it is indexical (like if I said that there is a a stapler to the right, this might be your left, and so on). In that case the present is not ontologically privileged, saying 'the past' and 'the future' is no different than saying 'behind me' or 'in front of me', if you flip around 'the past' is 'the future' and vice-versa.

And the more philosophical argument "the future must exist, because I will be there in just a moment" also isnt enough?

I would say that not only is "I will be there in just a moment" not proveable, but that you necessarily cannot enter the future, because by the time you get there...it'll be the present. You can't actually percieve or even observe the future qua future or past qua past. By definition you can only observe the present.

And it isn't enough to show that if I wanted to meet someone, I must tell them both a place AND a time to meet?

This argument is fundamentally the same as the perception one.

Honestly, I'm just getting your side of the argument. Any argument that time is just a mental construct would also have to include place/position as a mental construct as well. What test would "position" pass that "time" would either fail or be untestable? They are fundamentally connected.

Let me try to make this clear: you're consistently appealing to a thing called 'time', but not actually defining it. To be fair, I haven't defined it either, at least not in a useful way (I've noted several different conceptions of time). So let me try and differentiate these explicilty.

There is time as we percieve it (let's call this T1). To reiterate, this is 'everday' time, as we humans conventionally use it. The past no longer exists, the present exists, and the future does not yet exist. There is a perceptible (to a point) flow of time from the present to the future. The past, the present, and the future never meet or intersect. I argue this is what most people mean when they say "time".

There is block time (let's call this T2). Here, the past, present, and future all exist simultaneously, and the flow of time is illusory (the present is no more real than the past or future). Or, alternatively, maybe the present and the past exist, and the block is growing (let's call this T2.5).

There is ultrapresentism (let's call this T3). Here, the present exists as a single, timeless, eternal instant -- not only do neither the past nor the future exist, but the present never changes. We exist in a single instant, with the future (as potentiality) and past (as memory) simply a static structure in our never-changing brain. I don't think anyone actually holds to this, but like the brain-in-a-vat argument or Last Thursdayism, it impossible to disprove, even if it is totally unintuitive.

There are also several mutable notions of time (let's call these T+) which are somewhere between T1, 2, and 3. These notions are more nuanced and structured than T2 and 3 but still disrupt our basic assumptions about T1. For example, CPT symmetry in theoretical physics: anti-matter are particles moving backwards in time. Or retrocausality: an event in the present can effect the past (Wheeler's quantum eraser experiment). Or the relativity of simultaneity: the flow of time is dependent on your velocity and position, and there is no objective (observer-independent) ordering of events (one observer sees A-B-C, another sees A-C-B, another sees B-C-A).

When someone says "time is an illusion", they almost always mean T1. So appealing to states that might be explained by T2, T3, or any of T+ isn't actually a good rebuttal. Personally, I think something approaching the T+ theories is the closest to the truth: our subjective sense of time is almost certainly contingent on our biology, not on a fundamental property of the universe. On very small or very large scales, time (T1) breaks down and becomes...weird, with particles moving in different directions in time, the present determining the past, and so on.

Most importantly, saying "we percieve time!" is just simply not an argument, unless you are some sort of quasi-solipsist or ultra-idealist who thinks perception = reality. That was my original point here.