A new argument for God

Here's an argument for God I came up with today (11/30/2025). I don't know if it's a good argument. I just came up with it. But here it is.

1. If there is no God, then you are a Boltzmann brain.
2. You are not a Boltzmann brain.
3. Therefore, there is a God.

Defense of the first premise

According to the standard model in cosmology (Λ-CDM), the expansion of the universe is accelerating. That means the universe will never recollapse. It will expand forever.

In the meantime, entropy will go up until the universe reaches thermodynamic equilibrum. Once it does, the only thing that will ever happens is that over vast oceans of time, there will be random low entropy fluctuations.

Small fluctuations will be more frequent than large fluctuations, but as long as something has some positive probability of happening, it will happen. It is possible for particles in equilibrium to spontaneously organize itself into the form of a human brain, even if just for a moment. In fact, that is vastly more probable than there being enough particles that spontaneously all organize themselves into a single location and become a whole universe populated with sentient beings like us.

With that being the case, the entire history of our universe should have vastly more isolated brains that fluctuate into existence than real people like us. And with that being the case, it's vastly more probable that you are one of these brains than it is that you're a real person.

According to Christian theology, that is not the fate of our universe. At some point, God is going to intervene. He's going to make everything new. He's going to raise physical people to eternal life. The earth will be our home forever. That requires some drastic change to the universe that should prevent the universe from ever reaching thermodynamic equilibrium. That, in turn, will prevent the emergence of Boltzmann brains.

If the Christian God doesn't exist, and no other God exists to prevent nature from taking its course, then we probably are Boltzmann brains.

The only way to avoid this conclusion is to suppose that Λ-CDM is not correct. It may not be. I've blogged on that a few times before. But right now, it's the prevailing view of cosmologists, and the evidence favours Λ-CDM. If new evidence comes in that overturns Λ-CDM, that's all well and good. But for the moment, we ought to incline our belief to where the evidence currently points, and that's Λ-CDM.

So if there is no God, then you probably are a Boltzmann brain.

Defense of the second premise

However, it is not reasonable to think you are a Boltzmann brain. If you were a Boltzmann brain, then you would not have reliable belief-producing cognitive abilities. The reason is because everything you know and experience just randomly fluctuated into being along with your brain. It has no connection to reality. You can't possibly know anything about the real world if all your thoughts and sensations just randomly fluctuated into being.

It's not reasonable to think you are a Boltzmann brain because if you were, it would undermine any reason you had for thinking you were a Boltzmann brain. If you came to that belief because of your "knowledge" of cosmology, but none of that "knowledge" was reliable, then you have no reason to think you are a Boltzmann brain. The belief that you are a Boltzmann brain is self-defeating since it undermines everything you believe.

To be a rational person, you must affirm the second premise in my argument. You must deny that you are a Boltzmann brain.

If you are a not a Boltzmann brain, but you would be if there were no God, then there must be a God.

That's the argument in a nutshell.

A possible objections and response

I can think of at least one objection to this argument. Recall what I said before about leaning in favor of Λ-CDM because it's the prevailing view, and that's where all the evidence currently points. One could just as well use this argument to show that Λ-CDM is false rather than saying God exists. You could make an argument like this:

1. If Λ-CDM is true, then you are a Boltzmann brain.
2. You are not a Boltzmann brain.
3. Therefore, Λ-CDM is not true.

With this argument in place, you wouldn't need to invoke God in order to avoid being a Boltzmann brain. I guess the question would come down to which is most likely to be false - that God exists or that Λ-CDM is true.

There isn't much evidence against the existence of God, which is why it's so popular for people to say they lack a belief in God rather than saying they believe God doesn't exist. Nobody wants to have to prove a negative, so they don't claim God doesn't exist.

Λ-CDM has some evidence against it, but so far it hasn't been overturned. So far, the evidence still seems to favor Λ-CDM.

With little or no evidence against the existence of God, and plenty of evidence for Λ-CDM, it seems more reasonable to affirm Λ-CDM than to deny God. That means the argument for God at the beginning of this post is probably sound and the argument against Λ-CDM is probably not sound.

I don't know, though. Λ-CDM isn't really a complete picture of the cosmos. Maybe there will be some irreversible process in the future, other than increasing entropy or divine intervention, that will prevent Boltzmann brains from ever forming.

If everything spreads out forever, I don't see how it's possible for there to be spontaneous fluctuations of low entropy that produce Boltzmann brains. Everything would be too far apart.

But maybe that's just the point. In animations I've seen on YouTube that explain entropy and the second law of thermodynamics, they'll show a box filled with gas that's evenly spread out and everything is in motion. But then, given enough time, there should be a point at which the molecules somehow all end up in one small corner of the box. It's unlikely, but given enough time, it can happen. That would be a random fluctuation of low entropy.

So maybe, even though everything in the universe is really spread out, it's possible for some particles to spontaneously gather in different places and have localizes regions of low entropy.

What do you think?