One of the nagging mysteries of modern physics is something called the “Fine-tuned Universe” question. It has to do with the fact that our universe has properties that are exactly what’s needed for life to exist. However, our best understanding of these properties seems to indicate that it’s much more likely for the universe to be simpler, so much simpler that life could not exist, so that it’s incredibly unlikely to have just the right properties. The reason for this has to do with the nature of physical laws and how they depend on a small number of constants that seem to have random values. There seems to be no reason for the constants to have the values that they do have, so out of all possible values, why these very particular ones?

Some people have dismissed the whole issue, trying to explain it away as an artifact of the way we approach things, or the result of our limited understanding. However, the mainstream scientific view is that this is a very valid question, one for which we should seek some answer.

The most accepted answer seems to be that reality actually consists of a multitude of different universes, each with different values for the physical constants. This is called the “multiverse”. There are several theories for how these come to be, but the general idea is that there are so many of these different universes that some of them are bound to have characteristics that support life, no matter how unlikely that would be. We live in one of those universes.

While existence of the multiverse is allowed by recent physics, it is not required, and there is no evidence for any other universes. In fact, it may not be possible to ever have any evidence because the other universes would be completely separate from our own. This may also make it impossible to prove that different universes do not exist. So at the moment, their existence must remain a matter of pure speculation.

Nevertheless, the multiverse is considered a valid possibility, and it certainly does solve the problem. Let’s call this the M-hypothesis.

The other common answer is to invoke some sort of creator deity. The basic idea here is that a willful act created the universe we see with the parameters needed to support life. Let’s call this the T-hypothesis. There is no proof of the T-hypotheses, but there is some evidence. This evidence is mainly in the form of human experiences that are attributed to the supernatural, and observations of extraordinary events for which natural explanations seem insufficient.

It’s easy to discount this evidence, especially since some of it has been challenged. For example, a new field of inquiry called the cognitive science of religion is discovering natural explanations for a few of the human experiences. However, this is new work and only applies to a small part of the evidence. So while there is no scientific basis for the T-hypothesis, there is also no way to disprove it. Therefore it is also a valid possibility.

We now have two hypotheses: the M-hypothesis, which has some scientific basis but no supporting evidence; and the T-hypothesis, which has some evidence but no scientific basis. It seems hard to choose one over the other based on the scanty information we have.

If both choices are reasonable but there’s not enough information for certainty, then preferring one over the other is a willful choice, rather than a logical one. Many factors other than pure reason may lead us towards one conclusion or another — upbringing, love, experience of the divine, lack of such experiences, awe, playing the odds, etc. The choice basically makes a statement about the nature of reality at a level for which there simply is not yet certainty, so the trick is to describe one’s reasons without trying to pretend they are the result of logical thinking.

And that’s OK, because much of human experience exists outside logical thinking.