h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Yes, Hell, I asked you. I have no problems with including something into the Edited Guide that I don't believe, if it is only a certain assumption of the entry that I think is improbable, and the rest is exciting. But in this case it is different.

I think that the article contains serious weaknesses in its internal argumentation, and this is something that must be tackled before any including.

Just to make this clear, that the universe is in fact probably finite is not my problem with this article.

However, I simply do not believe that an infinite universe leads to a universe containing all sorts of stuff. And emphasis is on 'all'. I don't see the cogent and complete logical step. As long as Adon can't give this, the entry doesn't get my personal, subjective, and humble okay.

The entry is well written and nice. And I may be wrong. To be honest in this case I'd like to be wrong, because it's pretty exciting and I'd love to retell it to my friends.

Ok, first of all i spotted one semi-typo, in the desclaimer you said "about as close to one hundred percent as if can be with out being one hundred" or something like that. It should probably have a "percent" at the end as well.

Now onto content. One basic point. I'm not sure it you should have 2nd person in your entry (you), you definately can't have 1st person (I), maybe you should use "one" as in: "if one chooses an alien".

The actual theory is not as widly accepted as you make it out to be. I think one of the most common theories is the "the universe if finite but unbounded" in other words it doesn't have an edge but it isn't infinite, a bit like a circle. Don't ask me to explain it, its a bit like quantum mechanics in that respect.

I think the best way to do this entry is to find someone (possibly yourself) to write a bit about why the universe is finite, and put them together as a balanced agruement.

The theory is an interesting one, and mathematically sound. (as far as i can tell) Some commented that infinitly close to 100 is equal to 100, and i think that is the point the auther is trying to make, is it not?

In brief, it needs work, but don't give up on it yet.

Tango

Well, you've got a point there Cefpret.

I don't think we can - even in principle - find out the true answer. To do that we must be outside the universe.

PLUS: If the universe has infinetly small scales it is also infinite. You don't need just one border (+infinity or -infinity). Adon's argument that the Universe cannot be infinite because otherwise I would be getting an oil massage from Cindy Crawford is indeed not really cogent... at least not from my perspective ( No. She's not right here giving me a massage - just in case you asked).


HELL
(I'd like to Fourier transform the Universe one of these days.)

Oh, Tango, you don't need quantum physics to explain how the universe (probably) looks like:

Imagine a flat world. A world where everything has only two dimensions. All people are flat, all planets, well, everything.

It's flat, but not planar. This world is in fact the surface of a sphere that is constantly expanding. For the flat people, their universe has no boundaries, but it's not infinitely big.

Now add a dimension to this imagination and you have a quite good impression what the universe looks like -- according to current textbooks.

To Hell: Gödel's theorems were about axiom systems, if I remember correctly. I don't think you can apply them to physical problems.

physical problems are axiom systems.

The example you describe is pretty much what Gödel said.

Only if you can see the disk-world from outside you can tell it's finite. (can you? fractals?) From the inside it is impossible.

HELL

well, the whole universe can not imagined untill we beyond time and space during our this physical existence on this planet which is quite within time and space.....Do you believe on such statements.

However, the ones who try to visualise upto that extent as you wishfully desire, they do that most possibly by virtue of their intuitive clairvoyant power latent in them or they develop that skill through spiritual practice......

Truely yours,

A.R.Shams

I didn't mean you needed quantumn physics to explain it, i just meant is was hard to get your head round, like quantumn physics. Your sphere explanation is like the circle one i mentioned in passing. The problem with both these explanations is it takes unbounded to mean, you can go in an direction and get back where you started. Which is not certain.

Sorry Shams I don't understand you

HELL

Well, according to Gauß'es 'theorema egregium' the flat people don't have to leave their cosmos in order to find out: they can measure the curvature of space and then they can say whether their world is finite and how it looks like. However, the voyage that would be necessary for this would be very long.

Maybe you are referring to something of Gödel that I don't know (although I'd never claim to be one of those 176 people of mankind's history who have understood what he said), but Gödel proved that

-- There are (under certain circumstances) theorems that can't be deduced from the axioms, although they are true.

-- You can't guarantee that your axiomatic system is free from contradictions, unless you change to a more comprehensive axiomatic system.

But we are talking here about something like 'you can't see how the house looks like as long as you are inside it'. That's not a mathematical problem.

Maybe not, but it's a physical one.

Gödel proved that:

-- no set of axioms (no matter how bitchen) can be used to completely describe itself.

-- Your axiomatic system either contains a contradiction or you cannot make certain assertions.

Hence: You cannot fully describe the universe if you are a part of it. EIther you get contradicting stuff, or you don't know which explanation to choose.

Sorry, but I'll stop here. I don't think that this discussion will lead us anywhere. All I am saying is: We'll never know if the universe is finite or not. Everything else is mere conjecture.

Bye,

HELL

You're right, and I am not really competent as far as Gödel is concerned.

But in principle we can say whether our world is finite or not. I don't see anything that could made this impossible ...


Okay, be that as it may, now it's up to Adon to explain the missing links.

First of all, Hell, I did not say that in an infinite universe Cindy Crawford would be massaging oil into your back. I don't know who brought that up or why, but it makes little sense.

I don't follow all this disk-work and axioms...and I'm not trying to prove the infinity of the universe; I personally do not believe that it is infinite. I am merely saying that IF it is infinite, there is a high probability that everything that can be out there is out there. That is all that I'm trying to convey.

Well, the probability that Hell enjoys a message from Cindy is certainly not zero. So, if you are consequent, then according to your theory, in an infinite universe there is out there an alien exactly like Hell, with his appearance, his memories, on a planet exactly like this Earth in Septemper 2002, with a counterpart of Cefpret, a counterpart of Grand Moff Adon, only with one difference: Cindy is giving Hell a massage.

Adon, your entry is worth for the Edited Guide even if many people, including yourself, think that the universe is finite, since we still don't know exactly. However, I have another problem and have said so:

I don't think that in an infinite universe you could find every sort of things. This could only be true if something ensures that everything has a finitely small probability. But some things may simply be impossible. And an infinitely large universe wouldn't change that.

I have stated that anything possible (the key word being possible) will almost definitely be out there. I'm not saying WHAT is possible, so maybe the imagined alien in my article isn't possible. Is that the error you see? If so, I suppose I can emphasize the importance of "possibility."

And yes, according to the theory, I suppose there would be another Hell and another Cindy Crawford out there somewhere.

And now for the tricky part: What *is* possible?

Adon: The point of the conversation above was the following. I think that there is no strict way to answer that question, ie. if the universe is finite or not. One of the reasons IMO is Gödels theorem. Cefpret was saying that it should be possible to determine whether the universe has boundaries or not. I think we were talking about two slightly different things there, and maybe that's why you got confused. I was talking about the problem of finity/infinity which may or may not have boundaries (cf. integer numbers versus rational numbers - both have clear boundaries, but are infinite. Or for example the set of all numbers smaller than 1 and bigger than 0. Infinite, but with clear boundaries) Cefpret was talking about boundaries/no boundaries (only latter would necessarily imply an infinite universe, whereas for the first one anything goes - right Cefpret?

HELL

No idea ... boundaries but infinite? You mean your fractal thing?

Please let's go away from the question whether the universe is infinite or not. First, we don't know, secondly, that's not the problem of the article.

Without any (eg Internet) references I won't give my personal subjective humble okay for this entry. Sorry. I'm still missing a couple of logical steps in it.

Cef: Well, okay, I don't want to discuss that either, it's just that Adon asked. And, while we're at it, no I didn't mean the fractal stuff. I meant: The set of real numbers between 0 and 1 (the boundaries) contains infinite numbers; it is infinetly big - so to speak. Hence things can be infinite AND have boundaries.

BTW, somehow that is too -maybe not mainly- the problem of this Entry. I agree, however, with the rest. That is: That there are some logical things to be resolved in the Entry - Oh, and some links would definetly be fine.

See you around people, thanks for listening...

HELL

IMHO this is not the stuff of the EG for the following reasons:

It seems to me to be inspired by the passage from one of DNA's books (I'm not sure which one) where he says something to the affect; that in an infinite universe all things will occur naturally somewhere. The example being mattresses growing in a swamp on some far off planet or something like that (Its a long time since I read these books). Now this made for a good read in a humorous and fiction novel, but I not sure it makes a good factual article.

It is desperately short of facts. Central to the article is the Universe being infinite. But the one fact that stands out is "many who consider themselves knowledgeable of such things don't believe it. They believe the universe is extremely large, and constantly expanding, but not infinite." You, GMD appear to be one of those knowledgeable people who believe that the universe is finite. So the article is based on a weak, if not false, premise. Even if we accept that the universe just might be infinite, it does not mean that every thing in it is also infinite. Thus you can have a finite number of varieties of "aliens" in an infinite universe.

It is a huge leap to say that in an infinite universe all things, that are possible, will be. I don't think the size of a place necessarily make unlikely occurrences more likely.

It seems to me to be completely false to simply multiply the chance of something happening by infinity purely on the basis of the universe being infinite, especially if that chance was infinitely small in the first place.

but that my opinion.

SK

I agree with HELL - we can't make assertions about the universe, and this entry isn't unsuitable for the Edited Guide. Just have a reference to that entry about Olbers' Paradox, so readers can get both sides and decide for themselves.

And perhaps fix the disclaimer...since it's speculation.

But a good read nonetheless.

Madame Sprots