Science a GoGo's Home Page Forums General Discussion Physics Forum Infinity and the present.

Sounds remarkably like faith.

All this time!!! All these posts!!!! I have given entirely the wrong impression about how I understand infinity.

Have to rush out now, but I'll be back.

Interesting. Thanks! It is good to see scientists? (Who are scientists here? And what is your field?) for discussing what I think of as the "sciences" of pneumatology and theology. IMO, a 'science' is any subject which we are willing to approach with an attitude of wonder, inquiry and philosophy.

Who among us believes there is only one category of science--the hard kind, which studies only concrete matter?

Me? IMO, there are three categories of science--hard, soft and 'O my G0D! what on earth is it?

Actually, you've given me the impression that you're unsure about how you see it...


...which is why I said 'perhaps'. Incidentally, I would say it's a matter of belief not faith, unless one regards the belief as significant to spiritual well-being - which, of course, may often be the case, since infinity has a foot in both camps (physics and metaphysics).

If I gave this impression it is probably because I am inclined to present my ideas somewhat tentatively to avoid appearing bigoted.
It would be presumptuous to suggest that I am any sort of "expert" on the subject of infinity, if, indeed there is any such thing, but I have done quite a lot of thinking about it, and have quite strong views.

Unfortunately, time is a bit short at present, but I will do my best to explain those views in the very near future.

Talking of experts, there's a very absorbing BBC Horizon program(-me ) called 'To Infinity and Beyond', in which experts give their sometimes contrasting views on the subject. The word 'believe' crops up a number of times. There's another Horizon prog called 'What happened Before the Big Bang?' which presents the change of thinking among cosmologists during the past 10 yrs, and has much to do with 'infinity'.

Anyone, have you heard of the Perimeter Institute For Theoritical Physics in Waterloo, Ontario, Canada?

www.perimeterinstitute.ca

I have not forgotten that I said I would have a go explaining my views on infinity. I have been pulling together my notes. So far this amounts to almost 7,000 words. Far too much to post, and a lot of it is probably waffle. Lots of distilling to do, but let's hope that, like a good malt, it will be worth it in the end.

Go for it Bill S.

7000 words from you is not a waste of real estate.

Thanks Kirby, but I think I have to shrink it a bit. Perhaps I can use some of it by way of a response to a comment by the other Bill.



I agree that movement in infinity seems possible, but is it as straightforward as it might appear?

Those who have been following similar discussions in other threads will recall an example involving Alice and Bob, alone in an infinity void. I apologise for any repetition.

Consider the following. Those intrepid adventurers Alice and Bob, in their respective space craft, are the only occupants of an infinite void. Each perceives her/him self to be at the centre of the void. There is an infinity of void extending in every direction. This sounds like being at the centre of a sphere, but it makes no sense to describe infinity as spherical. A sphere has, by the very fact of being a sphere, a boundary surface; infinity does not. However far you travel in infinity, you will never reach a boundary. A sphere has one fixed centre, but as the perceptions of Alice and Bob have already shown, there is no fixed centre to infinity, nor would it matter how far apart they were, they would still have infinity in every direction.

What changes when Alice or Bob moves? Any movement that either, or both, may make is movement relative to the other, not movement relative to the infinite void. Inevitably this leads to the conclusion that whatever movement you make in infinity makes no actual difference to your position in infinity. Before you move you are at the central point; after you move you are at the central point, but you were already there, so have you moved?

Before we leave Alice and Bob in the void, consider one more strange thing. Suppose that Alice and Bob are an infinite distance apart; if each moves, say, a billion light years towards the other, are they still an infinite distance apart? Intuitively, it might feel as though they should be two billion light years closer to each other, but that would mean that the distance between them was less than infinite. If the distance between them is less than infinite, it must be finite. This means that something that was infinite has become finite. Reverse their journey and something finite suddenly becomes infinite. This is impossible. It seems that if they are an infinite distance apart, however they may move, the distance between them will always remain infinite. Perhaps the logical conclusion to draw from this is that in infinity, distance has no relevance at all.

Whatever relevance distance might or might not have in infinity, it does seem that the occupants of infinity can move relative to one another, but not relative to the infinite background. There is a ring of familiarity here; this scenario has a distinctly Einstienian feel. In 4-dimensional spacetime we can move relative to one another, but can identify no static background against which we can establish absolute motion or rest. Given that relative movement is, at least in theory, possible in infinity, we must look at the question of time, because movement is change and change requires time in which to happen. However, we should not lose sight of the fact that there is a major difference between spacetime, as we experience it, and infinity. In spacetime we can identify no static background against which we can measure motion, but having said that, there is no way we can know with certainty that it is not actually possible to move relative to spacetime. In infinity, it is infinity itself that seems to provide that background, but here we can establish that movement relative to that background is not possible.

Bill S. In your write up about Bob and Alice in the last paragraph
you say "there is no way we can know with certainty that it is
not actually possible to move relative to spacetime". I have
a problem with that because we are a part of spacetime. We can
move relative to another part of spacetime, but obviously we
cannot move relative to what we are a part of. You are correct
when you say that if only Alice and Bob exist in spacetime,
which may or may not be infinite, they can move only with
respect to each other. As I see it it they are infinitely far
apart then they essentially do not exist to each other. There
is no way for them to interact. Beyond that I don't see that
there is much that is very realistic about the situation in
any case. Thinking about it it seems that we may be in a
situation similar to the irresistible force and the immovable
object. A situation which can not in fact exist.

Bill Gill

Bill, The bit about Alice and Bob being an infinite distance apart was not intended to represent a realistic situation. My intention was to look at the non-feasibility of interchange between finite and infinite, in either direction.



I think we are saying much the same thing, except that you say "obviously we cannot move relative to what we are a part of". I would ask how you know that for certain. It seems obvious, but is it?

I don't think it is quite as drastic as that; I think what we need to do is clarify the relationship between the finite and the infinite, and maintain a distinction between mathematical infinities and the real thing.

Sounds easy!!

Ok, I think this will be my last post on this subject.

You question my question my statement that we can't move relative
to what we are a part of. Well, if we can please explain how, I
feel no need to speculate on wild assumptions.

As far as physical infinities are concerned, physicists don't
like them. Whenever a theory produces infinities they tend
to produce effects that are at odds with our observations of
how the world is. So they try to find a way to work around them.
An example is the ultraviolet catastrophe. Classical physics
showed that any energy applied to an object would be radiated
at extremely short wave lengths, approaching infinity. things
obviously didn't do this, so Planck developed the idea that
energy came in quanta, related to the constant bearing his name.
In quantum physics they kept coming up with infinities in their
calculations. These infinities, as said, led to totally
unobserved phenomena. When they developed renormalization
their calculations started working.

As far as the universe is concerned, it is not infinite and
will never become so. Current theories set the size of the
universe at about 93 billion light years (per Wikipedia).
Since it is expanding at a non-infinite speed it will never
reach infinity, assuming that it does continue expanding.
I believe there is some doubt as to whether there are an
infinite number of points in the universe. It depends on
the ultimate structure of space, which of course is an
area of intense theoretical research.

And of course questions about what spacetime is are
rather more philosophical than scientific.

Bill Gill

I was not actually speculating about the possibility of our being able to move relative to spacetime, I was simply observing that although I could find a logical argument against being able to move relative to an infinite background, I was not at all sure I could do the same for spacetime. In view of your comment, I was hoping you could.

This is precisely how I see it. However, I find it very difficult to accept that there can have been a time when there was nothing; so something must be infinite (eternal).