Is there genuinely good evidence that the universe could have been eternal/infinite into the past?

[Jeremiah Ames]

Think of a number line. To make it a bit easier, let's constrain it to just the numbers between 0 and 1. To get from 0 to 1 you'd first have to pass the half point at 0.5 (or 1/2). Then you'd have to pass half of the remainder, another 1/4 to 3/4. There are infinite many steps to take, even if you have a beginning. It is impossible to reach "now" either way.

very interesting

I appreciate you providing that example

especially since I’m partial to numbers

 

[Jos]

If the universe is expanding, at an ever increasing rate, there would be nothing observable at this point, had it always existed.

Hmm, that makes sense

 

[Jos]

How do they explain the redshifting in distant galaxies or cosmic background radiation?

Idk, I'm no expert lol

 

[Jos]

Currently our best understanding is that over 14 billion years ago everything in the universe was contained in something like a small compact singularity. Think of it like an nuclear explosion, how all of the tremendous energy released from a nuclear explosion comes from splitting a tiny atom that can't even be seen with the naked eye. So over 14 billion years ago this singularity started to expand/explode in what we call the Big Bang. That's when the universe started existing in its current form. At this point that's all we can say with any degree of certainty.

Did the singularity always exist? That's a tough question, since our concept of time didn't exist prior to the Big Bang, but the honest answer is we don't know. IF there's some sort of 'cosmic time' beyond the space/time continuum that we currently exist in, we have no way of knowing if the singularity always existed in some form or not.

What sparked the Big Bang? Again, we don't have enough information to provide an answer. Theists will claim that it was some creator god that caused it, but there's no evidence to back it up. It could just as easily be that singularities expanding in such fashion is simply what singularities naturally do.

So no, an uncreated/beginning less universe isn't just wishful thinking. In fact, considering that the our entire understanding of the current universe is based on it being a natural process, it could be said that it's insisting that some creator being had to have intervened to spark the expansion instead of it being a natural occurrence that's closer to wishful thinking.

So don't bother thinking about it then? Since there's so much that we don't know?

 

[Jos]

As I understand, infinity is a ''limit'' not a number, per se. So, from my faith view point, God has always existed. To me, there isn't much of a contradiction in saying that the universe is both eternal, and had a beginning point.

How can infinity be a limit if it's literally defined as something unlimited? And I don't understand how there's not a contradiction in saying that the universe is eternal yet also had a beginning since eternal means always existing with no beginning or end.

 

[Jos]

Philosophy is used by far to many people to prove to themselves anything that strikes their fancy happens to be true.

Sometimes yes but not all the time. It's still a very useful tool, in fact, without philosophy, science wouldn't exist.

 

[Jos]

I'm at a keyboard now.

Cosmology doesn't have a direct answer to this. Direct observation into the past (by looking out to large redshifts) is limited by the time of last scattering, beyond which the universe was opaque. Everything beyond the surface of last scattering is extrapolated with well-understood mechanisms (some of which have made some of the best predictions to match experimental observation in the history of science).

So we already have the problem that there isn't direct observation, even though looking "out" is looking "back."

The other problem is that we do not have a working theory of quantum gravity, which would be necessary to really understand what was going on when the universe's size was on the order of the Planck scale. This includes understanding what would have been occurring around the Planck time after the Big Bang event.

Since time's arrow is given by the entropic gradient, and it's questionable what sort of entropic events would be happening on the order of one Planck time, it's not even really clear whether the concept of having a "time before the first Planck time" even has cognitive meaning.

This is a really roundabout way of saying "there isn't sufficient data, and the question might be wrong in the first place." Asking what was "before" the Planck time may well be like asking what's north of the North Pole.

Having said that, though, there is the concept of metatime. Temporal dimensions are always characterized by gradients, and there may be other gradients by which to give time an arrow than this universe's entropic gradient. For instance, the best way to understand this is by imagining a hypothetical multiverse where new universes are created: within each universe, there is a beginning to time (the entropic maximum for that universe), but overall there is a more encompassing metatime.

And this brings me to the most direct possible answer to your question: do we have good reasons to think there might be an infinite past?

The answer is "yes, but..."

The "yes" portion is that if inflation is true (and it has every appearance of being true), then it's really hard to avoid a multiverse because the inflaton fields decay asymmetrically, leading to "bubble universes" where it has decayed (and ours would be one such example). While inflation decayed here, it is still ongoing elsewhere, and has no reason to ever end, and no reason to have ever began.

The "but" portion is that while inflation is a scientific inquiry in terms of the local universe, I wouldn't strictly call eternal inflation elsewhere scientific because we can't empirically observe it: we have to leave the realm of pure science and enter the realm of philosophy to make those kinds of assertions. I am not saying that means the assertions are without evidence or without good reasons to think them, however.

Let me wrap this already-too-long response up by saying this: what we can say for sure is that there is zero evidence that the universe ontologically began to exist, even with the Big Bang (the most we can say is that its present local state began). This means that it remains a possibility that the universe is infinite and eternal. I am not sure how that could be shown, however.

Thanks for taking the time to respond to my question and simplifying it as much as possible. I'm gonna have to read over a couple things a few times to understand them but overall I think I get what you're saying. Can you please explain the difference between the universe itself and the present local state? Cause I'm struggling to see the difference between the two.

 

[Jos]

Maybe you will find philosophical arguments.

I guess so, there are few like the WLC argument from impossibility of infinity but those have their own issues.

 

[Jos]

You can't put borders on beginning and endings.

It's impossible. Because everything has dimension and dynamics which goes into infinity.

Essentially you cannot contain any beginning or ending like a box because there's always going to be an 'outside' of that box.

So that means we're infinite beings then?

 

[Jos]

Do arguments by William Lane Craig have that much worth that they should be considered? Theories range from no universe (Advaita Hinduism, my style) to universes cropping up at each Planck's moment.

I know he's no cosmologist and some physicists heavily disagree with him but his arguments are interesting.

 

[Jos]

Time before and time after exist only in the imagination. Beginnings and endings are functions of the manner in which we, subjective beings that we are, experience time. If time is not linear, then it may have neither beginning nor end. Why should it?

All we have is the now, the eternal expanding moment, but we are rarely able to experience that moment because we are distracted by two illusions; memories of the past, and anticipation of the future.

I don’t suppose that helps much with the OPs questions; except perhaps to suggest that the way we think about time, and everything we think we know about it, is limited by our imaginations, and probably does not reflect it’s true nature.

So again, if beginnings and endings don't actually exist, then we're infinite beings then?

 

[Jos]

There is no final answer, yet. Therefore its possible, Scientifically speaking, that the universe has no age. The Big Bang shows some sort of age, but the existence of Quantum foam (which is not theoretical but definitely is measurable) suggests that we don't really know what space is or whether the universe has an age.

So why believe that the universe is 14 billion years then?

 

[Jos]

Well, yeah it does. Most everyone on this forum asks that question in one way or another.
My attempt to answer it is:
All we are sure of is the observation. It is quite possible that observation is all that exists and not its objects. If all that exists is now, then past and future are simply ways of structuring now. Since we appear to be many and we share observations, my question expands to whose or what's observation. I find the closest attempt to answer that lies in the prayer: "Our father who art in heaven...Thy will be done in earth as it is in heaven..."
This seems to me a reference to a mental universe. I won't label the mentality. That just gets me into trouble.

So our minds create reality?

 

[Jos]

Think of a number line. To make it a bit easier, let's constrain it to just the numbers between 0 and 1. To get from 0 to 1 you'd first have to pass the half point at 0.5 (or 1/2). Then you'd have to pass half of the remainder, another 1/4 to 3/4. There are infinite many steps to take, even if you have a beginning. It is impossible to reach "now" either way.

That's kinda WLC's argument, which is that an infinite past can't allow us to get to now.

 

[Jos]

He may be able to answer you, but if you aren't a mathematician yourself, you'd likely not understand the answer.

Yeah I'm struggling to understand it.

 

[Jos]

Hi, Jos! I have an argument for an infinite past.

So, most apologists claim we should accept the universe had a cause (if it began) because we never observe things beginning to exist without a cause and we always observe things being caused. Ergo, it is much more likely the first event also had a cause. (But not all say that; some say we have a metaphysical intuition against that possibility).

My argument is that we also never observed a moment that had no temporal predecessor. In fact, all moments we have observed have temporal predecessors. Therefore, we should conclude all moments have temporal predecessors. But if we conclude that, then an infinite past is necessary since a finite past would necessarily entail some moment had no temporal predecessor.

Now, this is prima facie reason to accept a beginningless time-line. Here apologists would try to argue against this possibility by saying an infinite past is impossible or that cosmology provides evidence of an absolute beginning.

However, these arguments are wrong. I've written an entire post (very heavy and extensive) refuting scientific arguments, and I also addressed philosophical arguments.

Cosmology: Does Modern Cosmology Prove the Universe Had a Beginning?

Philosophy: A Critical Examination of the Kalam Cosmological Fallacy

Feel free to check it out. Then tell me what you think about it.

Thanks man, I'll give it a look and get back to you and welcome to the forum!

 

[Jos]

i always thought the universe was around 13 billion years old, and had no reason to question it

How come?

 

[Jeremiah Ames]

How come?

that is a very good question

 

[Magical Wand]

Thanks man, I'll give it a look and get back to you and welcome to the forum!

Thanks.

 

[Heyo]

That's kinda WLC's argument, which is that an infinite past can't allow us to get to now.

Yes, only this is about a finite past. And you know something is weird when you can't have a finite past and can't have an infinite past. The existence of the universe is a paradox either way.
If there was a beginning, what was there before the beginning?
If there was no beginning, then why was there the Big Bang 13.8 billion years ago (and not at any time before)?
I have yet to find someone who can get out of the paradox. Those who pretend to have found a way, just stopped thinking at a convenient point.
We need an intuitive way to divide one infinity by another and come out with a sensible answer. We solved Zeno's paradoxa (more or less) and the existence of the universe is a Zeno type paradoxon.