I'd argue that matter cannot exist forever; see points 1-6 in the OP.

I give more arguments against the possibility of 'infinite existence' here:

https://thephilosophyforum.com/discussion/5242/infinite-being/p1

Seems to me that there is an assumption here that logic tells the universe what to do. I don't think it works that way. Rather, we choose a logic - a language or grammar - that best suits what the universe does.

So the line of philosophising that you adopt is fraught with potential error. A better way, the physicist way, is to find a language that describes what is going on... to do experiments and theorise using mathematical models that suit what you see.

The style of argument you use in this OP - and elsewhere - is that adopted by medieval monks to show that God exists. Just as with those arguments, no one was convinced except the monks.

Rather, we choose a logic - a language or grammar - that best suits what the universe does. — Banno

Putnam attempted to make a case for this regarding so-called quantum logic. Is that what you're talking about?

better way, the physicist way, is to find a language that describes what is going on... to do experiments and theorise using mathematical models that suit what you see. — Banno

Physicists do attempt to describe, but being prepared to embrace some counter logic is problematic. How would we know when to choose another logic and when to persevere looking for answers that fit the logic we have?

There was a time when physicists aimed for recording data and limited theorizing. It's pretty clear that those days are gone, though.

So no, I think you're wrong.

So no, I think you're wrong. — frank

Refreshingly direct.

I'm not sure what a "counter logic" is. What I'm referring to is the various sorts of mathematics that are drawn into the mix. Nor am I suggesting that they somehow limit theorising... anything goes, if it works.

Seems to me that there is an assumption here that logic tells the universe what to do. I don't think it works that way. Rather, we choose a logic - a language or grammar - that best suits what the universe does. — Banno

I think there is an assumption in my argument that the universe won't do anything deeply illogical or magical. I think you will find the same assumption is used very extensively in science and in our everyday lives. Without this 'no magic' axiom, we would have made little progress in science.

So the line of philosophising that you adopt is fraught with potential error. A better way, the physicist way, is to find a language that describes what is going on... to do experiments and theorise using mathematical models that suit what you see — Banno

I've given a theoretical argument; its true some empirical evidence is needed to back it up. I can point to the Big Bang; time slows down the closer we get to the Big Bang; so that looks like supporting empirical evidence for a start of time. We then can look at the low entropy nature of our universe and take that too as evidence for a start of time. It would be better to have more empirical evidence than this but it is hard to collect empirical evidence for something that happened 14 billion years ago.

The style of argument you use in this OP - and elsewhere - is that adopted by medieval monks to show that God exists. Just as with those arguments, no one was convinced except the monks. — Banno

You are referring to the prime mover / first cause arguments of St Thomas Aquinas? These arguments have stood the test of time. I believe they are still valid: once you allow that quantum fluctuations lead to infinite density so are impossible as a cause of the universe then cause and effect is back as an axiom and so there is no reason to doubt the prime mover / first cause argument except in its general abstractness. It shows there must logically be a first cause. That it not the same thing as demonstrating the existence of God I grant.

I'm not sure what a "counter logic" is. — Banno

You mentioned a choice, so I thought you were picturing numerous options. As Devans99 pointed out, we wouldn't get far trying to arrive at fundamental logical principles empirically. And scientists don't proceed that way. Both relativity and quantum mechanics have thought experiments in their ancestries. So we start with reliance on logic.

Where we end up with conclusions that defy common sense, we still at least hold out hope of discovering underlying logic (of the ancient sort).

If we someday give up on a logical approach, we'll probably wonder if we're intellectually limited and in need of some evolution. IOW, we dont think in terms of options for logic that we choose by empirical justification. We think that if ancient logic is wrong, we'll begin a quest to discover the truth, without knowing how we will find it.

I think there is an assumption in my argument that the universe won't do anything deeply illogical or magical. I think you will find the same assumption is used very extensively in science and in our everyday lives. Without this 'no magic' axiom, we would have made little progress in science. — Devans99

I agree, more or less, but I would explain this rather than accept it as a sort of miracle. When the universe acts in ways that are a bit odd, what scientists do is to change their theory to match. So when Jupiter is found to be the centre of its own little solar system, or when particles act like waves, we don't just accept that this is contrary to what we expected, but instead we change what is being said to match what we see. It's not an axiom, it's a way of using words.

I've given a theoretical argument; its true some empirical evidence is needed to back it up. I can point to the Big Bang; time slows down the closer we get to the Big Bang; so that looks like supporting empirical evidence for a start of time. We then can look at the low entropy nature of our universe and take that too as evidence for a start of time. It would be better to have more empirical evidence than this but it is hard to collect empirical evidence for something that happened 14 billion years ago. — Devans99

Meh. Your science here is questionable. Let's leave that as moot.

You are referring to the prime mover / first cause arguments of St Thomas Aquinas? These arguments have stood the test of time. I believe they are still valid: once you allow that quantum fluctuations lead to infinite density so are impossible as a cause of the universe then cause and effect is back as an axiom and so there is no reason to doubt the prime mover / first cause argument except in its general abstractness. It shows there must logically be a first cause. That it not the same thing as demonstrating the existence of God I grant. — Devans99

No, I'm referring to the general style of arguing from any sort of first principle to a self-serving conclusion. They are examples of confirmation bias, not of philosophy. If you assume there is a first cause, it will not be surprising that you can conclude, validly, that there is a first cause. But no one else need agree with you. They are dreadful arguments.

It would be an error to think that the universe acts logically. Instead, we choose logical descriptions of the universe. The universe acts as it will; it's our descriptions that are "restricted" by logic. If our descriptions do not work, we don't conclude that he universe is being perverse, we change the description.

We can't "give up on logic" and still be saying anything interesting.

No, I'm referring to the general style of arguing from any sort of first principle to a self-serving conclusion. They are examples of confirmation bias, not of philosophy. If you assume there is a first cause, it will not be surprising that you can conclude, validly, that there is a first cause. But no one else need agree with you. They are dreadful arguments. — Banno

I was not trying to reach a self-serving conclusion - I am not religious. I'm just trying to discover the truth.

Aquinas did not assume a first cause; he argued from cause and effect to a first cause. I do not assume a first cause or even cause and effect in my arguments. Why do you say a first cause has been assumed?

Look again.

I do not assume a first cause. All the points in the OP are numbered or lettered.

If you would be kind enough to point to where I assume a first cause?

I'm not challenging the validity of your argument. I'm challenging the style.

It is an example of the sort of argument Wittgenstein described as an engine spinning without engaging with the road.

But the validity is also questionable.

X. ‘Can get something from nothing’, IE matter is created naturally. With infinite time, matter density would be infinite. So this is impossible. — Devans99

Not in an infinite space.

Y. ‘Can’t get something from nothing’, IE matter has always existed. Meaning the matter had no temporal start. So this is impossible too* — Devans99

If time has no beginning, why couldn't matter also have no beginning...

But now I am playing your word game. None of this is significant. It's not physics.

1. Assume a particle does not have a (temporal) start point
2. If the particle does not have a start, then it cannot have a ‘next to start’ (because that would qualify as a start)
3. So particle does not have a next to start (by Modus Ponens on [1] and [2]).
4. And so on for next to, next to start, all the way to time start+∞ (IE now)
5. Implies particle does not have a (temporal) end
6. Implies particle never existed — Devans99

IT would be simple to take this argument's logic and show that there are no integers. Assume there is no first integer. Then there cannot be any next integer...

Not in an infinite space. — Banno

But matter is appearing in every possible place in the universe - Big Bangs are occurring all over through natural processes. It does not matter if space is infinite, it still reaches infinite density everywhere if time is infinite.

IT would be simple to take this argument's logic and show that there are no integers. Assume there is no first integer. Then there cannot be any next integer... — Banno

No you cannot do that; there is a first integer.

Eternalism is true

A. Assume only now exists (presentism)
B. So before the start of time there was nothing
C But creation ex nihilo / without time is impossible
D. So something 'other' than only now exists
E. The ‘other’ must be timeless (else we end up in a infinite regress of time1, time2, time3 etc...)
F. The ‘other’ must have created our time (at time=0)
G. So the ‘other’ ’sees’ time=0 and time=now simultaneously (its timeless)
H. Hence eternalism must hold — Devans99

If you assume only now exists, then there is no past, and hence no start to time. The argument falls apart.

If you assume only now exists, then there is no past, and hence no start to time. The argument falls apart. — Banno

Exactly... a start of time is impossible with presentism... so the argument moves on to consider eternalism.

But matter is appearing in every possible place in the universe - Big Bangs are occurring all over through natural processes. It does not matter if space is infinite, it still reaches infinite density everywhere if time is infinite. — Devans99

This makes no sense for me. There are no big bangs going on in my lounge-room; I would have noticed. And simple mathematics shows that your last sentence here is problematic. The sequence of reals contains infinite positive numbers, while leaving room for infinite negative numbers...

there is a first integer — Devans99

Really? What is it?

Exactly... a start of time is impossible with presentism... so the argument moves on to consider eternalism. — Devans99

So your argument becomes: Devans thinks there must be a start time, therefore presentism is wrong.

This makes no sense for me. There are no big bangs going on in my lounge-room; I would have noticed. And simple mathematics shows that your last sentence here is problematic. The sequence of reals contains infinite positive numbers, while leaving room for infinite negative numbers... — Banno

But we are assuming that 'something comes from nothing' naturally. So for arguments sake, I've said that matter is created during Big Bangs. They would be very occasional events but with infinite time, there would be an infinite number of them so matter would reach infinite density.

And it is your maths that is letting you down; if you have a fixed volume of space with infinite matter in it then density is infinite. It does not matter that space is infinite - matter is appearing everywhere.

Really? What is it? — Banno

The first integer is conventionally chosen as 1 or 0.

So your argument becomes: Devans thinks there must be a start time, therefore presentism is wrong. — Banno

The first part of my argument proves there is a start of time. Then that result is used for the proof of eternalism.

You could try reading it before criticising it.

But we are assuming that 'something comes from nothing' naturally. So for arguments sake, I've said that matter is created during Big Bangs. They would be very occasional events but with infinite time, there would be an infinite number of them so matter would reach infinite density. — Devans99

You might enjoy reading up on Steady State theory. The calculations you want were done last century.

You might enjoy reading up on Steady State theory. The calculations you want were done last century. — Banno

What calculations?

And it is your maths that is letting you down; if you have a fixed volume of space with infinite matter in it then density is infinite. It does not matter that space is infinite - matter is appearing everywhere. — Devans99

This appears incomplete. if you have a fixed volume of space with infinite matter in it then density is infinite - sure.

Hm. Have you ever visited Hilbert's Hotel? It will help with the mathematics.

The first integer is conventionally choose as 1 or 0. — Devans99

Says who? Devans?

The first part of my argument proves there is a start of time. — Devans99

Well, no. It shows instead that for presentism there is no start to time.

Oh, use Google. It was one hydrogen atom per volume of St Paul's per year, or some such. Not exactly a big bang. Read up on Fred Hoyle.