# Universe is infinite only in a theoretical sense?

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Wouldn't something have to be equally infinite on a deceasing scale as well as an increasing one to actually be infinite?

What does that mean? We are discussing whether the universe is infinite in extent. Where does "increasing scale" come into it?

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Ok let me clarify, in order to be infinite by extent it cannot have an end in whatever direction you travel. What I'm suggesting is would this not also equally apply to any definitive limitation we may encounter in the world of the very small. If indeed we do reach such a limitation couldn't it equally be considered a starting point and then given that everything that has a beginning must have an end wouldn't we then know that even on the largest possible scale the universe must have limitations and isn't infinite.

Edited by Nouveau
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Ok let me clarify, in order to be infinite by extent it cannot have an end in whatever direction you travel. What I'm suggesting is would this not also equally apply to any definitive limitation we may encounter in the world of the very small. If indeed we do reach such a limitation couldn't it equally be considered a starting point and then given that everything that has a beginning must have an end wouldn't we then know that even on the largest possible scale the universe must have limitations and isn't infinite.

I disagree with several of your assumptions.

Firstly, even if lengths are quantised at some scale (so that things cannot be any smaller than that size) I don't see any reason why that should imply anything about the extent of the universe.

Also, the statement that "everything that has a beginning must have an end" is clearly wrong. For example, take the natural numbers: they have a beginning (0 or 1, depending on definition) but no end. The same could apply physically: if the universe is infinite, then you could go on a journey that has a start (your home, for example) but has no end.

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Ok well thank you i've learned something. I must confess the concept of infinity not existing in both directions or actually having a starting point hadn't even occurred to me. I think this may well be educational to many others as well, cheers.

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Exactly my point. "Impossible is only impossible in the short term, there is a way to achieve anything, but it is impossible to us in the current because we have no knowledge of the existence of that way." -Anonymous

That's actually pretty close to the opposite of what I said.

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• 5 months later...

Perhaps I should say something, the concept of an infinity is irrational, as it is non definable. But at the same time there are bigger infinities than just infinity, in the same way 2 is greater than 1. However just being able to think of something in a conceptual way does not rationalize it. This is because just because you can think of 1 doesn't mean you can ignore the question of 1 what? What is 1? That is my mistake here. I said the universe is definable. The universe is an infinity, so we are able to rationalize that it is an infinity, but we are not able to rationalize infinity itself.

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The universe is an infinity, so we are able to rationalize that it is an infinity, but we are not able to rationalize infinity itself.

We don't know if it is or not infinite You can rationalise it by saying: it is any number greater than I can think of.

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Perhaps I should say something, the concept of an infinity is irrational, as it is non definable.

The concept of infinity is very well defined.

But at the same time there are bigger infinities than just infinity, in the same way 2 is greater than 1.

How are you able to say that if the concept is irrational and undefinable?

Although you are correct. (Presumably it was a lucky guess.)

The universe is an infinity, so we are able to rationalize that it is an infinity, but we are not able to rationalize infinity itself.

The universe may not be infinite.

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• 2 months later...

My mistake due to inexperience. Infinity is rational as well as well defined.

Google definitions: a number greater than any assignable quantity or countable number

So infinity is rational. But this post with it's belief is very clearly not. Please excuse my errors. I am still forming my knowledge of the universe.

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My mistake due to inexperience. Infinity is rational as well as well defined.

Google definitions: a number greater than any assignable quantity or countable number

So infinity is rational. But this post with it's belief is very clearly not. Please excuse my errors. I am still forming my knowledge of the universe.

20 years hence:

Please excuse my errors. I am still forming my knowledge of the universe.

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Please excuse my errors. I am still forming my knowledge of the universe.

As are we all!

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As are we all!

At least there's never going to be a shortage of things to research..... Here meet my wife:

The three stages of idiocy in scientific thought:

OH! THIS IS BRILLIANT!

I LOVE IT THIS IS GENIUS!!!! I LOVE PHYSICS!!!!

OH S%#^ IT'S COMPLETELY WRONG!!!!! I'M A DUMB!^#&

Lady Physics: I am infinite. You will never learn it all. But good luck trying. I eat minds like yours for breakfast

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