Belief and Beliefs: Can the existence of a god be proven or disproven?Thank you for a thought-provoking question that gives me an opportunity to argue against my usual position. It's fun to try to get your head on backwards sometimes!
I am tempted to rephrase the question as "What are some reasons to believe God DOES exist?", since I don't find any proof for the existence of God especially convincing. But I will resist this temptation because the "proof" phrasing is more interesting and a better challenge.
OK. Here's my best shot.
1. Proof from infinity that God exists, somewhere
Let's assume that there is an infinite number of universes in the multiverse and that those universes vary from one another in starting conditions, including physical laws that govern them. In one of those universes, there must exist an entity with attributes that would meet the necessary and sufficient definition of God. [FN1] Thus, God exists. Somewhere.[Fn2]
You will notice that this proof doesn't say anything about whether we happen to live in a God-inhabited universe. Can we make the leap to a proof that our universe is one of the universes inhabited by a God? Let's try.
2. Proof from frequency that God probably exists in this universe
Let's assume that the sets of physical laws that give rise to intelligent beings who ponder the existence of God is rare in the multiverse. Let's also assume that the sets of physical laws that lead to a universe being inhabited by a God are also rare.
Now let's make one further assumption. Let's assume that any universe inhabited by a God would contain very many instances of intelligent beings who ponder the existence of God, because God would, presumably, create many opportunities for such beings to exist. (God, could, for instance, create an infinite number of sub-universes within his universe, each containing an infinite number of intelligent beings.)
Thus, among the multiverse, the God-inhabited universes would contain a larger proportion of all intelligent beings that ponder God than the God-uninhabited universes.[FN3]
From these assumptions, we could argue that an intelligent being pondering the existence of God should conclude that (it/he/she) is more likely to be living in a God-inhabited universe than one that is God-uninhabited. [FN4]
. . .
Since the questioner specifically and politely asks that answers do not argue against the existence of God, I will leave the refutation of this (I hope amusing) argument to others.
[FN1] Of course, this reasoning applies to almost any other entity. The Easter Bunny exists somewhere in the multiverse. I should note here that there is a difficult unanswered question implied by the proof about constraints on variation in physical law among the universes. Is there a "meta-law" that limits the dimensions among which physical laws may vary? For example, is it possible to have a universe where a block of ice permanently persists in the middle of a star? If there is a meta-law, some entities may not "exist" even in the multiverse sense because the set of physical laws required by their definition is incoherent -- i.e., outside the region of possible variation specified by the meta-law.
ADDED on 2015-05-16
Thanks to Larry Woo for pointing out the need for a clarification on this point.
The argument from infinity requires that we assume that (1) an infinite number of universes exists, (2) that they vary in their physical laws in such a way that every possible combination of physical laws occurs, and (3) that a universe containing a god (or an Easter Bunny) is possible under some allowable set of physical laws. If all three are true than there must be at least one universe containing a god.
One could counter by asserting that a universe containing a god is impossible, and thus would not be found in an infinite set of possible universes, just as the number 4 would not be found in the infinite set of prime numbers. However, starting with this assumption seems, to me, a bit unfair in the context of the current argument that aims to find a proof that god exists! :) At least, it shifts the burden of proof to the person seeking to show that a universe containing a god is impossible under any allowable set of physical laws.
[FN2] Many places actually. In fact, there should be an infinite number of universes where there is a God.
[FN3] Here, we may need to make some tricky-to-articulate assumptions about ratios of non-God/God universes and the relative frequency of intelligent beings in these universes. This will include assumptions about whether each universe itself is infinite or finite, and that may require some serious thinking about ratios of transfinite sets. I'm going to ignore these difficulties here and hope someone else who understand transfinite numbers better than I do can clear up the muddle. The upshot is to make an argument that there are "more" instance of intelligent beings in the God-inhabited universes than in other universes.
[FN4] This whole bit is essentially the Oxford Philosopher Nick Bostrom's argument that we are living in a computer simulation, which I find very amusing and think everyone should read!
To provide proper attribution: I first heard a version of the simulation argument described in a striking way by the physicist Brian Green of Columbia University, but I don't remember the source -- I'm guessing it was probably on the Radio Lab podcast. http://en.wikipedia.org/wiki/Bri...