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

It's becoming clear that nothing will count as a 'reason' for you. Oddly, you've already said that 'if the universe were infinite we wouldn't be moving through it!. Since we are moving through it (agreed?) then it can't be infinite.

Gaffer, you've just read the summary. There are plenty of arguments as to why an actual infinite can't exist. Alternatively, what is the argument that the universe IS infinitely old?

But that's what I'm saying - I don't think we are moving through it (if by 'it' you mean time). The passage of time is a form of measurement created and employed by humans to stop things getting too confusing. As I said before this whole debate pretty much comes down to whether or not you believe time can be infinite. Either you think it isn't and that existence is finite, with a beginning and an end, or you think it is - or rather you think it doesn't exist at all and that the universe is eternal: no beginning, no end, no time at all. Obviously it's impossible to prove either opinion, all we can do is come up with theories.

Clearly, you think that theories can't ever produce conclusions. OK here's a thought that ends in an empirical fact. If the universe were infinitely old, and expanding as we observe it to be, then it would be infinitely large. If that were the case then (by Olber's paradox) all parts of the sky would be about as bright as the Sun, day and night. That ain't so, therefore the universe isn't infinitely old.

But what if, as I've already suggested, the universe is not simply the matter we observe to have expanded out from a central point - what if the universe is an infinite amount of empty space and this is just a cluster of debris expanding and contracting constantly forever? The theory you suggest works fine if you define the universe as matter, but if you don't it's just that - a theory.

If space contains debris, how can it be empty? It's pretty much accepted that there's no such thing as matterless space. Can you explain what it would be like.

There just isn't anything showing its presence from beyond 15 billion light years away.

OK, I give up. I'll just sit here and believe my unjustified, unevidenced beliefs and we can wait until the end of time to see who's right - if it ever comes, you win but if it doesn't..we'll never know.

Load of tosh Toxx! Galaxies don't last forever, neither do stars. There would not be infinite light. We do not know that the universe is expanding, we think it is but only because we don't think that anything has happened to the light in the 15,000,000,000 years it has been traveling through space.

Alji

I told you nobody had convincingly refuted it. There's an awful lot of reading to do if you want to Google it. You'd end up as a pretty useful philosopher and astrophysicist if you were to absorb it all.

Woohoo!!

Theoories do lead to conclusions. The problem is that the the ultimate test for a good theory is that its conclusions can be shown to be true by observation. The kalam theory falls down on this point (not in the sense of being PROVEN wrong, but of being not PROVABLE by any definite new prediction). Nor can I personally (though this could be my problem, not the theory's) give any concrete content to the term 'eternal'. Consequently I cannot give any reason why time should not be merely a frame of reference for a particular observer's view of an eternal universe, whatever that might mean.

Have we done this to death now?

Noggin

Look - the way I see it is we each have our own ideas about the universe and time and whatnot. We each have our own beliefs on the subject and it just so happens that these beliefs clash violently. The only difference is you seem to believe that your opinion is irrefutable fact, and I don't think it's possible for anyone's to be. It's obvious at this point that neither of us is going to convince the other so it's probably best that we stop this pointless back and forth crud and agree to disagree. Just please don't make self-righteous remarks reasserting your opinion as the empirically evidenced undeniable truth because a) It isn't (nyah nyah) and b) it means I have to come back and make a self-righteous remark in response reasserting the impossibility of there being an undeniable truth.
THE END

Well Alji, you clearly agree with my main point about the 15 billion years anyway. For my argument, nothing is required to last forever; no more than 15 billion years, in fact. The density of light emitting stars doesn't affect the paradox.

Noggin, you can forget it if you like. Some of us don't have your troubles with the reality of time.

I merely argue the case. In fact I'm an agnostic as I've already said so I DON'T accept that the kalam argument works! Further, I don't believe that there are any undeniable truths and have never claimed that there are. Why are you hitting at a straw man and then trying to close off any response?

"matter exploding out from a point only to be drawn back in and compressed to such a point that the pressure causes it to explode back out again."

actually I read soemwhere recently that this theory isn't as firm as it was and that, we may be expenading, but not contracting. I'll look see.

We still have this problem with time.
How do we account for the aging process, if time is a man made way of measuring existance.

The problem is we don't know if it is 15 billion years and it could be that we are looking out not loking in. What the Big Bang asks you to believe is that the light you can see is from the begining of time, but all matter in the galaxies was at the point where the light started from all those years ago.

Alji

Sorry, I thought you were saying that the universe had to be finite and could never possibly be seen any other way. I'm really just trying to back out of the discussion as all we seem to be doing is explaining our different opinions in different ways over and over.