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Harvard physicist: Occam’s razor cannot shave off multiverse

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Older (Ichthus, Fall 2013) but interesting Rudelius is apparently a Christian (“passionate about connecting students to Jesus Christ”):

The first bad argument against the multiverse is, as far as I can tell, a simple misunderstanding of conditional probabilities. The argument proceeds by analogy: suppose you are playing a game of poker, and your opponent deals himself four aces three times in a row. By the third time, you realize that he must be cheating, and draw your pistol. “Hold on a minute,” says your opponent, “In this infinite ensemble of worlds, there is an infinite number of poker games going on right now. And in some of these universes I am bound to deal myself four aces three times in a row. We just happen to live in one in which I do.” The argument, then, is that this reasoning certainly wouldn’t be enough to convince you not to shoot the guy, so therefore you should not follow similar reasoning when it comes to explaining how our universe happens to be the one in a zillion in which life exists.

The problem with this reasoning is that it fails to take into account the fact that we cannot possibly observe a universe that is not life-permitting, for if our universe did not permit life, then there would be no one around to observe it. In other words, the conditional probability that our universe permits life given that we live in it is 1. On the other hand, the probability that your opponent has dealt himself four aces three times in a row given that we happen to live in this universe is still extremely low. The analogy fails.

The other argument against the multiverse that I find unconvincing is an appeal to Occam’s razor: it is absurd, some would argue, to hypothesize an infinite number of other universes just to explain our own. It is simplest to assume that only one universe exists. Incidentally, atheists will often say the same thing about God, claiming that it is simpler to assume that just the natural universe exists rather than postulate a complicated entity like God to explain fine-tuning. The problem with both of these arguments is that Occam’s razor does not say that the simplest idea is usually the right one— it says that the simplest explanation is usually the right one. And if we rule out the multiverse and design, then we are stuck without any sort of explanation for fine-tuning. The problem of fine-tuning is not one that can be ignored, and whether we like it or not, the best proposed solutions to it are a) a multiverse or b) a cosmic designer.

Presumably this is an argument for the existence of God. If God had only his enemies to deal with… He often has much worse luck with his friends.

Note: Limited news posting today due to O’Leary’s alternate other day job.

See also: Cosmology is naturalism’s playground. But does the fun mask a science decline?

It is strange how many people will defend the resurrection and miracles of Jesus, for which there is no "scientific" evidence (there is some limited historical evidence) and yet look at the overwhelming scientific evidence for design in biology and physics and refuse to acknowledge God had any hand in this design. I have encountered numerous Christian pastors who do this. The reason is pretty obvious: they know that they can talk about the miracles in the Bible, and their atheist friends will just say, whatever. But if they question the absurd Darwinist attempt to explain away the obvious design in Nature, they know they will get hammered hard, because then they are treading on their atheist friends' religious beliefs. Granville Sewell
Rudelius' argument above is confused about the epistemology of statistical/forensic inference. If a scientific paper reports that "results were significant at the .0001 level", it doesn't mean that "odds against chance are 9,999 to 1": if P is true of reality, probability of P is 1: otherwise, it is 0. It really goes like this: We are likely to see likely outcomes. To test proposition P about the world, we model the probability of observing what we observe if P is true. In our model, its probability is .0001. This measures the strength of our epistemic justification for DISBELIEVING that P is true of the world: the smaller the level, the stronger our epistemic justification. Fnarb

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