Universe can't be infinite.

[attofishpi]

There would be a contingent aspect to the universe that would deem - you - a quadraplegic would not be worth having an argument with...i'll grant you that.

Way to dodge the point.

If I had no internet there would be no argument.

In your sad case because that;s where you draw your argument from.

If Earth exploded there would be no argument.

So the Earth exploded - hang on, was that not a part of the universe?

The observed consequence "no argument" has many possible causes

Your 'argument' has little reason...thus far.

[TimeSeeker]

Your 'argument' has little reason...thus far.

Since you insist on cherry-picking the examples I give you and you refuse to tackle the over-arching principle. I wonder if you would actually be willing to lay out your criteria for "reasonable" vs "unreasonable" argument.

You know - In the spirit of transparency and binary classification

I'd even bet money you can't do it!

Which lands us back on square one.

Is TimeSeeker's argument reasonable?

It's a yes/no question

Decision problem

decision.png (15.7 KiB) Viewed 2135 times

[attofishpi]

Your 'argument' has little reason...thus far.

Since you insist on cherry-picking the examples I give you and you refuse to tackle the over-arching principle. I wonder if you would actually be willing to lay out your criteria for "reasonable" vs "unreasonable" argument.

You know - In the spirit of transparency and binary classification

I love you dude. Im only saying that cos i've had a great night with great friends formed from many years of association - when you get to my age, you real eyes the ones that matter, and it typically makes up most of them!

But seriously, I know you want to get all deep on me but I've travelled the fathoms, and next time we'll go deeper on something where you weren't flawed at the outset! ...or we'll continue this one.

I'm as transparent as cling film and I comprehend the binary situation of the universe we are part of...better than most...

Best wishes.

[TimeSeeker]

No harm, no foul.

Decision theory is off-limits for philosophy

Actions speak louder than words (arguments?) and all that grandmother mumbo jumbo.

[devans99]

On the subject of the OP, the universe is expanding so it cannot be infinite in space else there would be nowhere to expand too. Infinity is the problem: it's larger than any possible thing. Yet we require it to expand; implying it was not larger than any possible thing. So surely the universe is finite spatially?

[TimeSeeker]

On the subject of the OP, the universe is expanding so it cannot be infinite in space else there would be nowhere to expand too. Infinity is the problem: it's larger than any possible thing. Yet we require it to expand; implying it was not larger than any possible thing. So surely the universe is finite spatially?

That's not what the "expansion" means. There is more Universe (spacetime) today than there was yesterday.

You could ask "Where does it come from?" or "Would it keep expanding indefinitely?" and "we don't know" answers both of those

[devans99]

That's not what the "expansion" means. There is more Universe (spacetime) today than there was yesterday.

If the universe is infinite that's impossible; only a finite universe can expand.

Also, the universe seems to have started with the Big Bang 14 Billion years ago and has been expanding since then; it should logically have a finite radius. Observations agree with theory on a finite universe.

[TimeSeeker]

That's not what the "expansion" means. There is more Universe (spacetime) today than there was yesterday.

If the universe is infinite that's impossible; only a finite universe can expand.

Also, the universe seems to have started with the Big Bang 14 Billion years ago and has been expanding since then; it should logically have a finite radius. Observations agree with theory on a finite universe.

You are trying to rely on intuition instead of mathematics.

Unfortunately, that doesn't work with physics.

[devans99]

You are trying to rely on intuition instead of mathematics.

Unfortunately, that doesn't work with physics.

If actual infinity existed as a mathematical quantity, it would be larger than any other quantity. But quantity + 1 > quantity, so no such quantity can exist and actual infinity therefore does not exist.

Actual infinity is just defined axiomatically in set theory; nowhere do they prove it exists and as you see from the above, its child's play to prove it does not exist.

[TimeSeeker]

You are trying to rely on intuition instead of mathematics.

Unfortunately, that doesn't work with physics.

If actual infinity existed as a mathematical quantity, it would be larger than any other quantity. But quantity + 1 > quantity, so no such quantity can exist and actual infinity therefore does not exist.

Actual infinity is just defined axiomatically in set theory; nowhere do they prove it exists and as you see from the above, its child's play to prove it does not exist.

Look, I don't like infinities in equations any more than you do and in the conventional sense they don't exist. https://en.wikipedia.org/wiki/Renormalization

But I also don't dislike infinities any less than negative; or imaginary; or complex numbers; or zeroes! None of those exist either! And so you need to keep about a sense of pragmatism. Mathematics is a tool! Mathematical objects have useful properties.

And precisely because infinities are placeholders they could represent any real-world object that BEHAVES like an infinity behaves in the context of the equation.

Consider ∞ + ∞ = ∞. What mathematical object when added to itself results in itself?
0 + 0 = 0. So infinity behaves exactly like 0!

Or ∞ * ∞ = ∞.
1 * 1 = 1,
0 * 0 = 0

Or ∞/∞ ?

Through various hacky mathematical tricks it can either be equal to 0, 2, ∞

∞ / ∞ = 0 this is new. No other mathematical object behaves this way.
∞ / ∞ = 2 so is this. Nothing divided by itself produces 2!

Anything divided by itself produces 1 (except 0).
But if you are familiar with mathematics you would reconise these as round-up and round-down errors.

∞ / ∞ = ∞ is the same as 1 / 1 = 1

And so "infinity" is a rather ambiguous mathematical object!

You need some sense of real-world behaviorism when doing mathematics.

[Ginkgo]

Hi everybody,

Consider universe as infinite. This means it has no beginning, no ending, no borders, no center. In every point you will be in it, you will have infinite points in front of you, infinite points behind you, infinite points below you, inifinite points above you, you will have inifinite points everywhere around you, so that you'll be the center of the universe. If you go on the Moon, you'll be in the same conditions, so that in an infinite universe there are infinite centers at any time, not none. But center can be only one, so infinite centers infinite universes. But infinite has neither beginning nor ending, so there can't be even two infinites, and universe can't be infinite.

As to whether the universe is finite or infinite depends on the shape of the universe. Is it open, closed or flat? In other words, negatively or positively curved.We now know the universe has negative curvature, this means the universe is flat. This also means that the universe is infinite.

[devans99]

And precisely because infinities are placeholders they could represent any real-world object that BEHAVES like an infinity behaves in the context of the equation.

There seems to be nothing in the real world that behaves like infinity:

∞ + 1 = ∞

What real world object can you add to and not change? Further, the above implies:

1 = 0

[TimeSeeker]

And precisely because infinities are placeholders they could represent any real-world object that BEHAVES like an infinity behaves in the context of the equation.

There seems to be nothing in the real world that behaves like infinity:

∞ + 1 = ∞

What real world object can you add to and not change? Further, the above implies:

1 = 0

You are just a stickler for rules. ∞ + 1 = ∞ is axiomatic. The axiom doesn't (have to) correspond to reality.

Nothing behaves like a negative number either. What world object can you add to and it gets smaller?

And just like you can think of adding negative numbers as subtraction, you can think of infinity in any way that's convenient for you.
The great thing about made up mathematical objects is that you can make up the rules too

∞ + 1 = ∞

so

∞/ ∞ + 1/ ∞ = ∞/ ∞

1 + 0 = 1

Or in the context of an inequality you could say:

∞ + 1 > ∞

Which is obviously true because:

1 > ∞ - ∞
1 > 0

Set theory is broken. Go with type theory.

In mathematics, logic, and computer science, type theory is a branch of computational logic that studies types, which informally, are attributes that objects can possess. In type theory, each object is a "term" of a definite type and operations on objects are restricted to those which are definitely terms of the relevant types. As a formal system, some type theories contend to be simultaneously an alternative foundation of mathematics to set theory, a programming language and a calculus for category theory

In type theory it is obvious to me that the infinity from the equality is different object from the infinity in the inequality!

The use of ∞ is ambiguous because these two cannot be true at the same time!

∞ + 1 > ∞ ∴ 1 > ∞ - ∞ ∴ 1 > 0

∞ + 1 = ∞ ∴ 1 = ∞ - ∞ ∴ 1 = 0

[devans99]

You are just a stickler for rules. ∞ + 1 = ∞ is axiomatic. The axiom doesn't (have to) correspond to reality.

The fact that it does not correspond to reality suggests that infinity is not part of reality. It's impossible to construct actual infinity geometrically or otherwise mathematically. We have no evidence for actual infinity occurring in nature at all. The whole concept is logically flawed; how could something infinite occur in the material world? Something bigger than anything else possible for example. That would just be magic so we should not consider it part of science.

Another way of looking at infinity is it is fundamentally undefined. For example the set of natural numbers:

{1, 2, 3, 4, 5, ...}

As you can see from the ... the set it only partially defined; IE it is undefined so it can't exist as a real object. All real objects have ends and infinity does not.

On the subject of the universe, negative infinity and past eternity share the same structure, IE:

..., -3, -2 , -1 , 0
..., 2015, 2016, 2017, 2018

Infinity does not exist, so neither does negative infinity, so neither does past eternity. IE time has a start.

[TimeSeeker]

You are just a stickler for rules. ∞ + 1 = ∞ is axiomatic. The axiom doesn't (have to) correspond to reality.

The fact that it does not correspond to reality suggests that infinity is not part of reality. It's impossible to construct actual infinity geometrically or otherwise mathematically. We have no evidence for actual infinity occurring in nature at all.

The whole concept is logically flawed; how could something infinite occur in the material world?

That is only the case if you care about correspondence. The same can be said about negative numbers, fractions, zeroes, complex numbers! They are not part of reality.

Physicists don't care about correspondence. They care about prediction. Utility!

This is where it's pertinent to differentiate idealism (philosophy) from science (pragmatism).

The universe has no obligation to adhere to man-made logic

Something bigger than anything else possible for example. That would just be magic so we should not consider it part of science.

Idealism vs pragmatism.

Another way of looking at infinity is it is fundamentally undefined. For example the set of natural numbers:

{1, 2, 3, 4, 5, ...}

As you can see from the ... the set it only partially defined; IE it is undefined so it can't exist as a real object. All real objects have ends and infinity does not.

On the subject of the universe, negative infinity and past eternity share the same structure, IE:

..., -3, -2 , -1 , 0
..., 2015, 2016, 2017, 2018

Infinity does not exist, so neither does negative infinity, so neither does past eternity. IE time has a start.

Idealism vs pragmatism.

Negative acceleration is deceleration.

As of the current (1-week-old revision) of the SI units "time" is defined in terms of the Cesium 133 atom.
Cesium atoms didn't exist "at the start". They came into being a few moments AFTER "the start".

So whatever we have defined time in terms of violates energy-conservation "laws"
And we happily turn a blind eye to all of that so we can make science work... Pragmatism!

You need more counter-factual thinking in your life...
https://en.wikipedia.org/wiki/Counterfactual_thinking