## From Infinity To Certainty?

Question from Blake (lost, then recovered – sorry Blake!):
If there is an unlimited number of universes with an unlimited number of possibilities, then would there be a universe in which there doesn’t exist other universes?

No.

Unlimited possibilities do not necessarily mean every possibility. The set of multiples of two (2, 4, 6, 8…) has infinite numbers, but no odd numbers because odd numbers are not multiples of two. The question uses the premise that there is an unlimited number of universes, and with that established the infinite universes you are not in are not negated by the one you are in, no matter what kind of universe it is. The basic qualities of the set of universes make a solitary universe impossible.

A similar argument is sometimes used to establish the existence of a god. See the piece that just went up. (That piece is the reason I found your question, due to similar subject matter.)

## The Great Big Arguments #9: Infinity

Basic form of the argument:
For all we know, the universe is infinite. There might even be infinite universes. However small the chance of a god existing in any given way, place or universe, the infinite possibilities make it practically certain that a god is out there somewhere.

This one crops up a great deal, but I have yet to see it formalised. A possible reason for this is that it doesn’t hold up very well when even basic mathematics are applied to it.

Firstly, the universe may not be infinite in whatever way matters. There may have been nothing of consequence before the Big Bang, or even no time so that “before” doesn’t even make sense. The multiverse may merely be a useful way of modelling the phenomena we see in the field of quantum mechanics, while not actually being real. Therefore the possibilities may not be infinite either, and a god may have only one chance to exist.

Secondly, the presence of an infinite element in a calculation does not automatically take the result to 100% or probability 1. The set of even numbers (2, 4, 6, 8…) is infinite but contains absolutely no odd numbers. You can calculate the digits in pi forever but they will never repeat themselves. The sum of an infinite set will be a finite number if each new number is a smaller percentage of the previous one, e.g. 1 + 1/2 + 1/4 + 1/8 + … = 2.

To speak more practically, if the multiverse is real there may well be things all universes have in common which preclude the existence of uncreated omnipotent beings. Super-advanced beings who have acquired godlike powers through evolution and technology over aeons, sure, possibly out there somewhere, but this supposition is an extrapolation of our own status and the technology we’ve developed so far, not a guess unrelated to anything we’ve ever seen before.

To make my answer as general as possible, there are any number of reasons why the probability of the existence of a god might be zero, making the number of different universes irrelevant. (Try to roll a 13 with two standard dice – you’d be there a while.) Even if it’s not zero, there are any number of reasons why a non-zero probability is not brute-forced to certainty by an infinite universe/multiverse. Infinite possibilities just mean there are things we can’t rule out, but I’ve never claimed to be certain that there are no gods.

## The Beginning Ain’t the Be-All and End-All

Question from John:
Universe had a beginning, “proved” by second law of thermodynamics.
Dear Sir, I understand that an argument used by creationists, in favour of a Universe that had a beginning, is that the second law of thermodynamics requires that it will inevitably wind down. In essence, the claim is that the universe can not have been infinite into the past as it would have inevitably already run down. The fact of a purported finite amount of usable energy therefore implies that the universe MUST have had a beginning or else we would not be here now to discuss this. Is there a scientific rebuttal to this claim please?

There are two principal possibilities which address the idea of an infinite universe having run down by now, both of which are centered around the concept of renewal.

1. The universe periodically contracts in a Big Crunch before a new Big Bang. This drags together not only all the matter in the universe but all the space and time as well. All the unusable energy lost to the edges of the universe is brought back to the singularity and can be useful once again.
2. The matter and energy in the hypothetical (but currently quite likely-looking) multiverse is infinite. When one universe runs down, countless others are still going and more universes spontaneously start up all the time. No laws of physics are broken by this sudden emergence if the amount of anti-matter that emerges is equal to the amount of matter, because matter and energy are conserved in an equation akin to 0 = 1 + -1.

Creationists often think, as they are told to by people like William Lane Craig, that once they establish that the universe had a beginning the argument is basically sewn up. Even if the above two possibilities are dismissed and you take it as read that the universe began, that it was begun by a god can only ever be an argument from ignorance. Without knowing how it happened, you can’t just assert it was one particular thing without eliminating all other possibilities, even the ones people haven’t thought of yet. The potential for spontaneous emergence from the “quantum foam” suggested by quantum mechanics, for one, ensures for the moment that well-formulated alternatives are out there, and you don’t even have to appeal to the un-thought-of.

## Eternal inflation? No. Eternal universe? Maybe, nevertheless. And what’s it to ya?

“These three scientists in particular, by virtue of their joint paper, are name-checked more often than any others by apologists not just arguing for an absolute beginning to the universe but claiming that this has been established beyond doubt.”

Question:
Scientists Arvin Borde, Alan Guth and Alexander Vilenkin, in their 2003 paper “Inflationary Spacetimes Are Incomplete in Past Directions”, ruled out past-eternal inflationary models of the universe. Does this prove that
1. the universe had an absolute beginning,
2. that it must have had a cause and
3. that the cause was God?

No, no and no.

These three scientists in particular, by virtue of their joint paper, are name-checked more often than any others by apologists not just arguing for an absolute beginning to the universe but claiming that this has been established beyond doubt. Apologists up to and including William Lane Craig do this to support the cosmological argument for God, which requires such a beginning to be indisputable.

So what does the paper actually say? Feel free to read it via the link above (it’s dense but short), but the thrust is in the title: spacetime can’t have been inflating infinitely into the past.

That seems obvious since you’d think you’d eventually reach a singularity if you worked backwards, but models have been proposed wherein the farther back you go the slower the expansion is. Some reasoned that perhaps the universe has spent eternity inflating extremely slowly from a size barely larger than a singularity, speeding up as it went along.

Borde, Guth and Vilenkin examined this idea and found, essentially, that it wouldn’t work in the real world. In doing so they pretty much dismissed every model of an expanding universe (or multiverse) that doesn’t involve a proper singularity and Big Bang. Therefore, according to apologists, the universe definitely had an absolute beginning, which must have had a cause, and that cause was God.

That’s going way too far because, for a start, the paper doesn’t take a position on whether the now-confirmed Big Bang was an absolute beginning. There are many more universe/multiverse models wherein the Big Bang was merely an event in an ongoing sequence – where the matter in the singularity came from somewhere, not nowhere. Borde et al only intended to rule out a family of models that clearly don’t work.

Get that? Borde, Guth and Vilenkin did NOT rule out an eternal universe, even if the result of their paper is correct. They merely ruled out one kind of eternal universe, the kind where the Big Bang never happened. The fact that there was a Big Bang does not mean there was nothing before the Big Bang.

The Big Bang as absolute zero, or an absolute beginning in general, is a poor platform for apologetics in any case. The idea that whatever begins to exist has a cause is not based on anything which physically began to exist in the same way the universe supposedly did, completely ex nihilo (literally “from nothing”). We’ve never seen anything like that happen, so:
1. it’s curious that so many people assume the universe came about in this way,
2. there’s no basis for assigning a cause if it did and
3. even if it had a cause, it’s a huge leap to declare it any kind of god, let alone someone’s specific personal deity.

SmartLX