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Multiverse and Rationality

Something that I was thinking about the other day: some people are familiar with Alvin Plantinga's evolutionary argument against naturalism. Basically it states that because people believe false things that help survivability (such as "god", from the naturalist's perspective), evolution does not favor minds that recognize truth, but minds that recognize how to survive- if a belief just happens to be true, it is pure coincidence.

However, I was contemplating the multiverse (or multiple worlds) hypothesis, and it seems that this only compounds the problem. For those uninitiated, multiverse theory states that our universe is not the only universe there is. There are many other universes that do exist; however, our instruments cannot detect them because they are outside our universe. This theory comes in several flavors, but the one I am talking about is the one that is capable of explaining the fine-tuning and design in the universe, along with being an alternative to God as the "banger" that the cosmological argument requires. In order to account for the fine-tuning of the physical constants of the universe, some naturalists posit that there are an infinite (or near infinite) number of universes, each possessing different constants of physics. Ours just happens to be the one that is amenable to advanced life, and that is why we exist to observe the "fine-tuning".


There are philosophical problems with positing an actual infinite number of anything (see William Lane Craig's articles about infinity). So, the naturalist is left with positing a definite number of universes, which they admit has to be astonishingly high to reasonably account for the fine-tuning of our universe for advanced life. However, if that number only takes into consideration the fine-tuning of the physical constants, it is astonishingly low. Here's how:

Going back to Plantinga's evolutionary argument against naturalism: how do we know that the way we think actually reflects reality? His answer is that we can't. Even if the universe is naturalistic (no god exists), then there is no way for us to know. In short, naturalism defeats its own foundation for making its claims of being true. Now, let's take this to the next level: the multiverse.

Since evolution could or could not produce a mind that is capable of recognizing truth, we have a need for at least two universes with the same physics (that initial number of universes just doubled). There is only one way to think rationally, but numerous (might I say "near infinite") ways to think irrationally. There is only one chance in whatever-number-that-is for evolution to produce a mind that can produce knowledge that accurately reflects reality. Because of the number of possible ways for a mind to think irrationally, the number of universes that have the same constants of physics that allow the production of life has not increased by multiples, but by orders of magnitude (exponents).

The less and less probable something is to happen, the fact that it did happen points more and more towards its happening being the product of a mind, not chance. Since we do not have evidence that necessarily demands the existence of these multiverses, the only consistent and rational explanation is still a Designer. If that conclusion is actually false, then that is a continued reason why we should still not trust our own minds to ever discover the truth of naturalism, and the multiverse provides exponentially less hope that we ever will. Ironically, if naturalism is true, God is still the best explanation for all the facts we have.

Other post that might be of interest:
Can You Trust Your Sense?