If you toss a coin 100 times, would you predict:

- All heads
- All tails
- 50/50

It's the 3rd. The question 'was the universe created?' is of the same nature - boolean answer, no reason to suspect a non-normal distribution in the answer, so 50/50 is the correct probability to assign.

Ah, okay, so you've changed your stance. You've scrapped the 50/50 thing — S

I think the question 'is there a God?' is not a 50/50 proposition.

But the question 'was the universe created?' is a 50/50 proposition.

Not necessarily. Even if there was infinite matter density, each part of the universe would only interact in relation to its environment. It does not mean that the potential for the whole universe would act in its absoluteness at every point. Also, there already have been multiple super and mega novas in this supposed universe since that hypothetical big-bang and matter still seems to be relatively well-organised. — BrianW

I'm not sure I follow, can you expand? I do not see how you can avoid infinite matter density with infinite time.

So, for me, if there's one universe, there's bound to be others. And why not? — BrianW

I think we'd have evidence. With infinite time, there should have been born, at each point in the universe, an infinite number of universes. They should all be overlapping each other. That is far from the uniform expansion that astronomy reports. The Big Bang looks like a singleton.

Just a big bang. They have discovered a lot of those and there's no guarantee that the one they reference as 'the big bang' is the first and only one of its kind. It is possible that with the hypothetical of a multiverse, there is potential for multiple big bangs for each universe. — BrianW

That sort of leads to a pet theory of mine: if big bangs were naturally occurring and time was infinite then there would be (with infinite time) infinite big bangs at each point in space leading to infinite matter density. So either the Big Bang was an unnatural singleton or time has a start.

I must admit I do not get these multiverse theories - at least in the most popular one (Eternal Inflation) you have a thing that generates universes - it must be connected (in space) to each of the generated universes. Therefore it follows that all universes are connected to all universes. In what sense is that a multiverse if they are all connected?

So you doubt the Big Bang theory? The red shifts of galaxies seem to clearly show expansion starting 13 billion years ago. The Cosmic Microwave Background radiation confirms the Big Bang also?

On the face of it, nothing can move relatively faster than the speed of light, so if galaxies are expanding faster than the speed of light; that suggests space itsself is expanding.

'The expansion of the universe is the increase of the distance between two distant parts of the universe with time. It is an intrinsic expansion whereby the scale of space itself changes. The universe does not expand "into" anything and does not require space to exist "outside" it. Technically, neither space nor objects in space move. Instead it is the metric governing the size and geometry of spacetime itself that changes in scale. Although light and objects within spacetime cannot travel faster than the speed of light, this limitation does not restrict the metric itself. To an observer it appears that space is expanding and all but the nearest galaxies are receding into the distance'

https://en.wikipedia.org/wiki/Expansion_of_the_universe

So it is the metric that is expanding.

Anyhow infinity is unmeasurable so has no size so cannot expand.

If the size is:

s0 at time 0
s1 at time 1
s2 at time 2

We have by the definition of expansion:

s0 < s1 < s2

So s0 can't be infinite.

There are not different sorts of infinity, but if you insist on this bullshit:

- We know that s0, s1, s2 are the same kind of infinity: aleph-one.
- The continuum hypothesis states that there are no intermediate cardinal numbers between aleph-null and aleph-one.
-We know aleph-one is s2, so means at best s1 us aleph-null and s0 IS ALWAYS FINITE.

The definition of expansion precludes infinity from growing.

Expansion means it is bigger now that it once was. So it can't have been infinite.

I asked if there are any sentient beings on any planet circling the nearest 25 stars to Sol. — Frank Apisa

The answer is 'yes, probably'. Not 'I don't know' because we have just discussed inductive evidence in favour of the proposition.

Where do we go from there? What are the implications of that? What is the point of you insisting that the universe cannot be infinite? — Frank Apisa

- It is a step in the road towards a better overall understanding of the universe. Cosmologists have models that are infinite in space or time. If we can eliminate these models, then the cosmologists can concentrate on the models that are possible.

- It is a step towards understanding the nature of infinity (it does not exist).

Okay...so you agree..."I do not know" is the answer — Frank Apisa

No: I think the answer is that there probably are aliens.

Probability is how we judge the merit of inductive truth, how we differentiate between weak and strong inductive truth. This is a more refined approach than guessing (but if you take a guess, probably your subconscious uses statistics anyway so there is no escaping probability).

We all have a set of assumptions or axioms about the real world we work to and that are mainly inductivity derived. Any inductive truth is prone to a certain margin of error. So I was wondering what your margin of error was?

I'm not dismissive of your questions... sorry if I missed any.

We would never know if there was sentient life in a nearby system - they are just too distant for us to be able to pick up artificial EMR.

We have a sample size of one solar system that says solar systems come with sentient life. It's dangerous to rely on a small sample size I know, but that is all the information we have.

So I feel a gambling man, if he had to make a bet, would bet on aliens.

99.999% certainty of the finding. It's a sort of gold standard for empirical evidence.

My point was at what threshold do you admit inductive evidence into the set of assumptions you hold about the real world?

I feel it is likely that there is life in nearby systems.

'The age of the Earth is about 4.54 billion years; the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago. There is evidence that life began much earlier.'

https://en.wikipedia.org/wiki/Earliest_known_life_forms

So evolution did not take long to get up and running here. I'd expect similar results on similar planets elsewhere.

I am finding your don't know / can't know attitude to most questions a little defeatist.

I think you should place more weight in inductive reasoning; it is this, rather than deductive reasoning, that guides us though our daily lives.

If CERN published an article claiming detection of a new particle at five nines certainty, what is your attitude? Do you adopt a working assumption that the particle exists? Or do you continue to assume it is unknown whether the particle exists?

Most Cosmologists would probably disagree with me... because they are mostly atheist and the Strong Anthropic Principle seems a bit like one of the 10 commandments in atheist terms.

Perhaps if there were other universes (not sure why scientists say there are other universes) where the laws of physics are different then i think the above might not be the case. — christian2017

The laws of math should be invariant across all such universes.

I am of the opinion if there are other universes, they will be like this one. They are all made of the same stuff, go through the same processes and end up at the same temperature/density so all universes should end up similar.

You maybe referring to the difference between Potential and Actual Infinity?

https://en.m.wikipedia.org/wiki/Actual_infinity

Its possible to keep counting indefinitely but even if you do you will never reach infinity (because it's impossible to count to infinity). So Potential Infinity is OK, but Actual Infinity never happens IMO.

It's impossible to construct something infinite as you'd never finish doing it.

In any case...the nonsense you posted above does not impact on my question...which talks about the planets circling the nearest 25 stars to Sol...not the universe.

By the way...to the best of our knowledge...no life exists except on planet Earth...not even in our system...which has billions of bodies circling the sun. — Frank Apisa

Even in our best instruments, large eco-planets appear as mere specks, so there is no way we are going to be able to detect life on them.

Earth is the only thing big enough to support an atmosphere within the the habitable zone so you would not expect life in the rest of the solar system.

Whether or not matter is discrete is still in contention...and probably will be for a very long time. — Frank Apisa

Are you suggesting a never-ending faberge egg style arrangement with an unending sequence of smaller and smaller sub-atomic particles?

Or are you suggesting we will discover a sub-atomic particle that is continuous (IE infinity divisible)?

Both seem rather far fetched so I lean heavily towards matter being discrete.

A statement is either true or false. If it is true that 'there is no objective truth' then that seems like a contradiction. — curiousnewbie

I think it is the case that the statement 'there is no objective truth' is an abbreviation for one of the following:

- 'There is no objective truth including this statement'. This is contradictory as you say.
- 'There is no objective truth apart from this statement'. This is not contradictory.

There is a difference between what can exist in our minds and in reality. In our minds it is perfectly possible to construct illogical things that can't exist. For example I can imagine a talking tree. Just the act of imagining something does not make it potentially real. To be potentially real, the object has to be realisable and logical.

Infinity is not realisable - its not possible to construct anything infinite in size (you would never finish)
Infinity is not logical - see above comments in previous posts.

What he said was:
(if it was size X, it is now size X+1, meaning X was not infinite)
— Devans99

Which is just false. Infinity plus one is still infinity. — Banno

But expansion says there exists a number X+1 (the new size) that is greater than X (the old size). So how exactly can X be infinite?

Anyway:

- ∞+1=∞ explicitly says infinity can't expand.
- Infinity is unmeasurable so it has no size so it can't expand.
- Infinity does not exist.

A Koch snowflake always has a finite perimeter length, the process that produces them is an example of Potential Infinity. If a Koch snowflake existed in reality it would have a finite perimeter (because matter is discrete). Does not matter how far you expand the snowflake, it still has a finite perimeter.

It seems the photon moves at the speed of light from our perspective but from the photon's perspective, it is covering no distance in no time to get anywhere so I'm not sure the notion of speed applies (speed = distance / time and time is zero so speed is undefined from the photon's perspective).

2. if ∞ derives a contradiction, then ∞ is illogical
and this is not the case in general; we have some examples of veridical paradoxes, which goes to show that ∞ can have counter-intuitive implications, and that's not the same as illogical; that said, there are some cases where we take a derived ∞ to indicate a problem; dealing with ∞ requires special care — jorndoe

My opinion is that the very conception of infinity is illogical. ∞+1=∞ implies the existence of something that when it is changed, it does not change. That is deeply illogical.

∞ ∉ R (not among the reals, requires different treatment) — jorndoe

My argument is that if infinity was a number X, then X would be greater than all other numbers. But X+1>X. So infinity is not a number.

My view is that spacetime started with the Big Bang 13 billion years ago and is expanding into 'nothingness' - no time / no space.

Nothingness itself cannot be said to be infinite (because it is nothing, it has no dimensions).

Well it is impossible for the universe to be infinite in size:

- Size is a number
- Infinity is not a number
- So the universe is not infinite in size

I would say as have many, often if indirectly, that you misuse "infinite." — tim wood

How so?

Quantums fluctuations create matter? Who says so? What does it mean to "create matter"? — tim wood

My argument works whether matter is created or not.

And, if every proposition you espoused were granted, you would be no closer to any ultimate answer, yes? Or if you think you would, then just go straight to that argument. — tim wood

Its a very simple argument:

1. There must be a first cause (see https://thephilosophyforum.com/discussion/comment/273119)
2. There is nothing logically prior to the first cause
3. So the only possible answer to 'why is there something rather than nothing?' is 'No reason'.

What are you objecting to?

I think you will find that energy is always conserved with quantum fluctuations - nothing persists - if it appears, it disappears.

And if it is not, I can argue that infinite time and quantum fluctuations lead to infinite matter density - impossible - so the existence of quantum fluctuations that create matter requires a start of time.

What is key to my argument is the existence of a timeless first cause and a start of time implies that.

Without a timeless first cause, we have an infinite regress of time which is impossible.

The point of this thread is to discuss whether the universe is infinite or not and maybe even reach a conclusion.

In the poetic or metaphoric sense wrt the universe, "infinite" just means large, the universe being the largest thing — tim wood

There is a danger of confusing very large with infinite. That is maybe what has happened to the universe; it is very large so it is convenient to approximate it with infinity and over time this has become a belief that it could actually be infinite in size.

I am aware that you can classify infinite sets via cardinal numbers. However calling them numbers seems to me a bit of a stretch. — CaZaNOx

And then some. Numbers have fixed values be they natural, real, matrix etc... Infinity has no fixed value so it cannot be a number.

Further my point was that the argument for the existence of infinity could be located precisely in the continuous growing of the value of integer numbers as done in math. I therefore don't see how the very same continuous growing would undermine asserting the concept of infinity to reality. — CaZaNOx

That would be a Potential Infinity which I do not object to. It is Actual Infinity that I believe does not exist.

I reformulate this as
1) Reality is not logical
2) Conclusion: The size of the universe is not infinite
(feel free to object to my paraphrasing your position if you think I misunderstood you) — CaZaNOx

What I meant was:

1) Reality is logical
2) Infinity is not logical
2) Conclusion: The size of the universe is part of reality so not infinite

This thread is just about if the universe is infinite in size or not. Whether the universe was created would be a separate thread.

Yes you create a new post and at the bottom click on 'poll'...

I have a 1st in maths so I am aware of set theory. The basic fact that set theory ignores is that the infinite is unmeasurable so cannot have a size/cardinality. Cantor just made up magic numbers for the cardinality of infinite sets - there is no math or logic behind it - it is just a fantasy of a deranged mind (Cantor thought that God was talking to him).

It would add weight to the general arguments against infinity if we could establish the universe has a finite size.

The fact that its impossible to create something infinite (you would never finish) is in itself suggestive the universe is finite (the universe is a creation - there is a start of time).

Creating something infinite is impossible (you would never finish creating it). Creating something finite is possible.

So the universe being finite does not imply creation but does allow creation.

I agree that infinity is not a number. I also believe there is a numerical property, the size of the universe, and this takes a number as a value (a concept is not a number).

I don't believe infinity is a logical concept and reality is logical so again the size of the universe is not infinite.

Afterall in math infinite is not understood as value thats why inf +1 = inf. — CaZaNOx

Maths claims that infinity is a number (at least set theory does).

Fundamentally the infinite is unmeasurable. If it is unmeasurable, it has no size. If it has no size it cannot be compared with anything else.