Roma

From what I understand, one theory about the universe says that it eventually pulls itself back into a tiny ball and goes bang, crunch, bang, over and over, ad infinitum. Let's call the set of all events that take place in between the Bang and the Crunch a "scenario." If matter is indeed eternal, and the Crunch/Bang system has been operating eternally, then would it be fair to say that every possible "scenario" (including the one we are currently living) has already occured an infinite amount of times?

-Roma

P.S. On a related note, at this point what IS the "most probable"/best/most respected theory for the origin of matter?

eh

The big crunch/big bang cyclic model seems to have been discarded these days. For one, there does not seem to be enough mass to allow gravity to halt and reverse the expansion. As well, even with a big crunch, no one knows how the contracting universe could possibly bounce back into an expanding phase.

However, there are other models that allow for an eternal universe. It would seem that in such a case, anything that is possible should have already happened an infinite number of times. That is, anything with a finite probability, will happen an infinite number of times. But what about individual human beings? Are there an infinite number of humans identical to you out there? I guess that depends on whether the probability of "you" is finite or infinitesimal.

Roma

Could you (or somebody) provide some examples or links about other eternal universe models? I was recently talking to my friend who said "well, I define God to be that which is eternal", and I used the bang/crunch model... etc. So I'd like to have some other models to show him since that one is apparently out to lunch.

-Roma

SanDiegoAtheist

Not necessarily true. There are different 'cardinalities' of infinities. For example, the number of one dimensional points on any two dimensional line is an example of infinity with a cardinality of 0. However, on a 3 dimensional surface containing that 2 dimensional line, the number of theoretical lines that can be drawn to intersect any of those points is infinitely greater than the number of points itself. This is an example of an infinity with cardinality 1.

While I don't know the theoretical infinites involved, my guess is that the cardinality of individuals residing within a universe of any given parameter is significantly higher than the cardinality of that universe itself - so even if this theoretical multiverse had created an infinite number of universes, it's possible that:

a) no particular universe with properties P has been created more than once
b) some possible universes have NEVER been created
and
c) even IF a particular universe with properties P has been created more than once, that some or all elements WITHIN those universes do not match with each other.

Cheers,

The San Diego Atheist

eh

Yikes, infinity makes my head hurt.

Roma, there are a few eternal universe models that come to mind:

One is the cyclic model based on M theory. Paul Steinhardt has a website at http://feynman.princeton.edu/~steinh/ and an animation of the brane collision model at http://feynman.princeton.edu/~steinh/brane2.html

Inflation could allow for a universe with no beginning or end as well. A link to one version of the theory is at http://news-service.stanford.edu/new...nflate127.html

The no boundary proposal describes a universe that is uncreated and eternal. A brief intro to the idea can be found at http://everythingforever.com/hawking.htm

I'm sure there are others, but these are the only ones that stand out in my mind.

AtomSmasher

You may be correct but I am having trouble with a particular concept: it seems that if the occurance of universes extends back into infinity, then the occurance of all possible outcomes would also occur an infinite number of times. I.E. for an infinite set, A, represented as the set of integers 0 to infinity, all subsets occur infinitely: for subset 0 to 1 of A there is .01, .001, on into infinity. If my comparison is true, therefore all possibilities would occur an infinite number of times.

SanDiegoAtheist

Nope. Doesn't work out when you're considering infinites. The problem is that we humans really aren't equipped to handle infinites. However, some infinites REALLY are greater than others.

It comes up when you have multiple dimensions or variables that can each be infinite. You can lay a one-to-one correspondence ONLY between one of those dimensions, but you have, in the case of a higher cardinality, not only that one-to-one correspondence, but the higher cardinality can also repeat that one-to-one correspondence with the lower cardinality an infinite amount of times (see my example above of a line, and lines drawn thru points on a line - theoretically, you can draw a 90 degree angle with one line each thru each point on the line, thus setting one infinity equal to another. But you can then draw an infinite amount of lines NOT at a 90% angle thru each point on that line, which is obviously greater than the infinity of points on that line, in fact, it MUST be an INFINITELY greater number of lines than points)

To use your example, the number of possible INTEGERS, while infinite, is infinitely smaller than the number of possible REAL numbers. The number of real numbers obviously include an infinite amount of numbers between each of the integers. You could lay a one-to-one correspondence between the infinity of integers, and the infinity between EACH PAIR of integers. Alternately, you can lay a one-to-one correspondence between the infinite number of integers that occur both in the set of integers, and the set of reals, yet still have an infinite number of real numbers in between each pair of integers. IOW, mathematically speaking, you can count from 0 to infinity using integers ONLY, and that would be an infinite number. Yet, while you were counting to infinity, you would NEVER ONCE count a .1, .01., .001, etc. So you have counted an infinity, yet not counted the infinite number of reals between those integers.

Interestingly enough, though my math is NOT good enough to prove it (though I have seen it proved, and it made sense, I'm just not good enough to do it myself), apparently, there are many of these infinities that we would THINK from similar reasoning to above, that would be higher cardinalities that aren't. For example, the infinity of positive integers is both equal to the infinity of negative integers AND the infinity of both positive AND negative integers. If an infinity varies ONLY in a finite number of dimensions (e.g. 2 dimensions, positive and negative integers, and the sum of the two), then it is NOT a higher cardinality. If the infinity can vary an infinite number of times (integers vs. reals) than it IS a higher cardinality. Maybe someone else can point you to a proof of this if you're interested.

A similar concept would seem to apply to a multiverse. While the multiverse would exist in a pseudo-time, it would spin off an infinite amount of universes - in fact, if the multiverse consists of an infinite amount of points on a 'plane' of some sort (rather than a 'timelike'-line, like a big-bang/crunch type of universe), it might be a higher cardinality of an infinity.

Now, if there are a FINITE number of variables that can vary infinitely for each universe (even if that finite number is very high - say each of the possible physical constants can be infinitely variable, but there are only a high, but finite number of them), then you CAN match that infinity up to the multiverses - and thus, every possible universe WOULD be created.

However, if there are an INFINITE number of variables that can vary infinitely for each universe (unknown, but certainly it appears logically possible), then you have a higher cardinality, and for each universe created, there would be an infinite number that never were created.

Of course, we don't know which is the case - so it's possible that we ARE repeated infinitely throughout the multiverse - but I wanted to point out to the posters above, that it's not necessarily true.

Cheers,

The San Diego Atheist