Harvard physicist: Occam’s razor cannot shave off multiverse
|July 17, 2017||Posted by News under Cosmology, Fine tuning, Intelligent Design, Multiverse|
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?