Your premise is that time is change. So "was" in the sense of "past time" is meaningless by that premise — Metaphysician Undercover

That comment simply makes no sense. I'm not saying anything like "There is no time." I'm in no way eliminating time. There is time. I'm simply saying what time is ontologically. Time is change. Past time is changes that have happened.

You completely ignored the entire content of the post explaining the issues by the way.

Even changing the entire universe wouldn't do it (especially if one is a nominalist). It's still two different instantiations of the "same thing" (in quotation marks because it's not literally the same thing).

Metaphysician Unlimited,

Would your premise be something like "If time isn't different than change/motion, then there would be no difference between motion/changes that are occurring, motion/changes that occurred, and motion/changes that have yet to occur"?

If that's your premise, you'd have to explain how you arrived at it, as it makes no sense to me.

I don't think you need a notion of "past change" in order to hold that when you change 1)A to B, 2)B to A and then 3) A to B again 1) is not identical to 3), unless the state you change is the state of the entire universe. Because under that condition, — Echarmion

1) and 3) are identical unless "A changes to B" does not mean the same thing as "A changes to B". But that would be nonsense if it didn't.

Because under that condition, 1) happens in a different universe from 3), and so the full descriptions of the states would not be identical. If you did change the entire state of the universe, then you would time travel, but since this presumably includes your internal state, you wouldn't notice. — Echarmion

I don't see where you get the premise that it would be a different universe. Anyway, "A changes to B" means the same thing as "A changes to B", and whatever universe your referring to is irrelevant unless you allow for violation of the law of identity..

That comment simply makes no sense. I'm not saying anything like "There is no time." I'm in no way eliminating time. There is time. I'm simply saying what time is ontologically. Time is change. Past time is changes that have happened.

You completely ignored the entire content of the post explaining the issues by the way. — Terrapin Station

I read your post, but it's not relevant to your premise that time is change, which is what I am interested in. So if time is change, and past time is changes that have happened, then how do we differentiate between changes which have already happened and changes which have not yet happened? You can't refer to time to make that differentiation, because time is simply change.

Would your premise be something like "If time isn't different than change/motion, then there would be no difference between motion/changes that are occurring, motion/changes that occurred, and motion/changes that have yet to occur"?

If that's your premise, you'd have to explain how you arrived at it, as it makes no sense to me. — Terrapin Station

I thought that it was obvious. Time is change, and nothing else. By what principle then would you differentiate between past changes, present changes and future changes. You cannot refer to time to differentiate these categories of change because time is change. That would be like differentiating the categories of change by referring to change. We can't do that we need a means for defining different types of change, past, present, and future. If time defines the types of change, then it is not simply change, but a defining aspect of change.

To differentiate categories of change (past, present and future), by referring to time, time must be something other than change. For example, to differentiate categories of objects according to size, size must be something other than an object.

I don't see where you get the premise that it would be a different universe. Anyway, "A changes to B" means the same thing as "A changes to B", and whatever universe your referring to is irrelevant unless you allow for violation of the law of identity.. — Metaphysician Undercover

Admittedly, my wording was imprecise at best. What I mean is this: Events in the universe are connected, the way we perceive this connection is as cause and effect. Any change that happens will propagate through the entire universe eventually. You can never have the same change again because the first change is already up and gone, having changed the universe. In order to do the exact same thing again, you'd need to recreate the exact universe that change happened in. But even if this were possible, it would preclude the notion of time "travel" because you'd have to somehow get out of the universe before it was recreated.

1) and 3) are identical unless "A changes to B" does not mean the same thing as "A changes to B". But that would be nonsense if it didn't. — Metaphysician Undercover

No two instances of something are actually identical. (I'm a nominalist.)

then how do we differentiate between changes which have already happened and changes which have not yet happened? — Metaphysician Undercover

You just said the difference. Changes that happened are different than changes that haven't happened. One thing happened. One has not. (And a third option is that it's a change that's happening.)

For example, think of your phenomenal experience. You watch a bird fly from one tree to another. As you're watching it, it's happening. Then you have a memory of it (which is another change after (watching) the bird flying from one tree to another). The change happened but is not happening. Maybe you'll experience the bird flying back to the first tree after that, but it hasn't happened yet.

That's the difference.

It's a brute fact of changes that they aren't all simultaneous. In terms of experience, you don't experience them all together. Just like it would be a brute fact about changes if they were all simultaneous, or you could experience them all together. Of course, the mere fact that there are changes at all means that change is not something that can be simultaneous--the idea of that is incoherent. It wouldn't be change if one thing didn't happen after another. For change to be change, one thing has to happen after another. That's what time is. Hence, time is change.

The only changes that exist, by the way, are the changes that are happening. Changes that happened existed, but no longer do. Changes that haven't happened do not yet exist, but they will.

And size is not something different than an object, either.

OK, then I agree, if A changes to B, that is a uniquely particular event which cannot be exactly replicated.

No two instances of something are actually identical. (I'm a nominalist.) — Terrapin Station

I agree, identical ought to mean one and the same. If they are two, then they are not identical. This is expressed by Leibniz as the identity of indiscernibles.

You just said the difference. Changes that happened are different than changes that haven't happened. One thing happened. One has not. (And a third option is that it's a change that's happening.) — Terrapin Station

OK, but if there is a difference between changes which have happened and changes which have not yet happened, then this is a temporal difference. Therefore time is something other than change. Or, is it your claim that the difference between future and past is not temporal?

And size is not something different than an object, either. — Terrapin Station

What? "Size" has the same meaning as "object"?

OK, but if there is a difference between changes which have happened and changes which have not yet happened, then this is a temporal difference. — Metaphysician Undercover

You don't think that I'm denying temporal differences, do you?

To tell you the truth, I don't know what you're denying. You have claimed time is change, and that's nonsense to me, so I'm trying to figure out exactly what you mean by this.

Time has different aspects, change is one, the difference between future and past is another. The two are not the same.

I'm not denying temporal differences, so pointing out that I'm specifying temporal differences isn't an argument against what I'm saying, it's a feature of what I'm saying. Yes, those are temporal differences. That's the whole point.

Let's try it this way: could you have a change or motion if one "thing" didn't happen after another "thing"?

I'm not denying temporal differences, so pointing out that I'm specifying temporal differences isn't an argument against what I'm saying, it's a feature of what I'm saying. Yes, those are temporal differences. That's the whole point. — Terrapin Station

"Time is change" is incompatible with "the difference between future and past is temporal", because this difference which is an aspect of time, is not itself a change. Future never changes into past. So, yes it is an argument against what you've said.

Let's try it this way: could you have a change or motion if one "thing" didn't happen after another "thing"? — Terrapin Station

I agree that change requires time, but this does not imply that time is change. To support your claim that time is change, I think you need to demonstrate that change is required for time. So let's try it this way. Could time pass without any change occurring?

So let's try it this way. Could time pass without any change occurring? — Metaphysician Undercover

No, of course not. And obviously I'd say that if I'm saying that time and change are identical.

Re "this difference which is an aspect of time, is not itself a change." It's a difference that's an aspect of change, because time and change are identical.

"Future never changes into past."

Of course. "Changes that haven't happened yet change into changes that already happened" is incoherent, isn't it?

No, of course not. And obviously I'd say that if I'm saying that time and change are identical. — Terrapin Station

OK, that's you're assertion. Can you justify it? I see no problem conceiving of time passing without any change. Imagine a very short period of time, Planck length or shorter. Physicists have determined that no physical change can occur in a shorter period of time. However, that short period of time must pass, and this time must pass without any physical change, according to what the physicists have determined. Therefore time passes without any change. To justify your assertion you need to demonstrate that this conception is impossible.

Of course. "Changes that haven't happened yet change into changes that already happened" is incoherent, isn't it? — Terrapin Station

Right, the difference between "changes that haven't happened yet" (future) and "changes that already happened" (past), is something other than a change. Therefore time is other than change.

according to what the physicists have determined. — Metaphysician Undercover

According to what specifically?

Wikipedia:
"The Planck time is by many physicists considered to be the shortest possible measurable time interval; however, this is still a matter of debate."

You just said that according to what physicists have determined, time shorter than Planck time must pass without any changes. You wrote "this time must pass without any physical change, according to what the physicists have determined"

I'm asking you for the support for that claim. How have physicists determined this?

I said:
"Physicists have determined that no physical change can occur in a shorter period of time."
My conclusion is that in a shorter period of time change does not occur.

You wrote "this time must pass without any physical change, according to what the physicists have determined"

I'm asking you about that.

Physicists have determined that physical change occurs in quantum units. I can conceive of a period of time shorter than the amount of time required for a quanta of physical change. This short period of time must pass without any physical change.

So when you say that something has been determined you mean that you and others can conceive of it?

I told you, this is my conception. to prove your assertion you need to demonstrate that my conception is impossible.

What I'm asking you about is your claim about physicsts determining something. Do you understand that?

I explained what I meant. Now you're just changing the subject because you have no defense for your assertion.

I explained what I meant. Now you're just changing the subject because you have no defense for your assertion. — Metaphysician Undercover

It's not changing the subject. You made a claim about physicists determining something, and that claim was part of an argument against my view.. Okay, so all you meant by "physicists have determined" is that you can conceive of something, is that right? I just want to confirm that first.

I have explained, and distinguished, between what has been determined by physicist, that change occurs in quantum units, and what I have conceived of, a period of time shorter than that required for a quantum of change.

I am sorry for any ambiguity, it was unintentional.

Can we proceed to the justification of your assertion, that time is change?

Can we proceed to the justification of your assertion, that time is change? — Metaphysician Undercover

I want to address your comments first. That's part of justifying this against alternate views.

Okay, so in your conception, does time passing without physical change amount to time passing via nonphysical change, or just no change at all?

I don't know what you would mean by "nonphysical change". You'd have to explain how such a thing could be possible.

Imagine a very short period of time, Planck length or shorter. Physicists have determined that no physical change can occur in a shorter period of time. — Metaphysician Undercover

Sorry to jump in on this discussion, but you contradict yourself. Physicists have determined no such thing, especially since this would violate conservation laws.

Wikipedia:
"The Planck time is by many physicists considered to be the shortest possible measurable time interval; however, this is still a matter of debate." — Metaphysician Undercover

You quote the definition, which is about measurable interval, and yet above you claim that no change takes place in that interval. It simply does not follow that something doesn't exist (small change) just because it cannot be measured.

I don't know what nonphysical anything would be. But who knows what you'd claim, and you specified physical change, as if there might be some other sort of change.

Okay, so you're using the word "pass" to refer to an absence of change? Could you explain that sense of "pass," as I'm unfamiliar with it.

I think that you cannot truthfully state that a change has taken place unless that change has been measured. To judge that a change has occurred is to have performed some kind of measurement. To say that a change has occurred, but it cannot be measured is contradictory, because to determine change is to make some sort of measurement.

don't know what nonphysical anything would be. But who knows what you'd claim, and you specified physical change, as if there might be some other sort of change. — Terrapin Station

That's the point, you're the one arguing time is change. Why would I accept time is a non-physical change as justification of your claim? You would need to explain what you mean by that.

Okay, so you're using the word "pass" to refer to an absence of change? Could you explain that sense of "pass," as I'm unfamiliar with it. — Terrapin Station

No, "pass" is not necessarily an absence of change, it can occur, as in the case of time, with an absence of change. I mean it in the sense of to proceed. Time may proceed without physical change.
If you insist that this procedure is some sort of change, then we'd have to consider the possibility of non-physical change. But that would require some explaining.