A simple response to the normalizability objection to the fine-tuning argument

The normalizability objection isn't necessarily an argument against fine-tuning. Rather, it's an argument against the idea that we can quantify fine-tuning or attach a specific probability to it. There are some people who think you need to be able to attach a number to a probability before probability makes any sense, but I want to challenge that idea.

Let's say you're standing in front of a wooden fence. As far as you can see to the left and to the right, the fence kind of disappears over a hill, through the trees, or maybe even out to the horizon. You don't know how far it goes beyond that point. As far as you can see in either direction, the fence is red. But there is one board right in front of you that's blue. You may have no idea how far the fence goes in either direction, but you can still see that the blue part is relatively tiny in comparison to the part you can see. Since you can't tell how far the fence goes, you can't normalize the probability that throwing a dart from any random location will result in sticking in the blue part rather than the red. But that doesn't prevent you from noticing that there's a lot more red than blue, and your dart is far more likely to hit the red part than the blue.

In the same way, you can tell that the life-permitting range is much smaller than the possible range of values to the fundamental constants and initial conditions of the universe. You can tell that changing the values by a small amount will result in a life-prohibiting universe without having to know the full range of possible values. So you don't need to know precisely how fine-tuned the universe is to know that it's fine-tuned.

I think this is what Robin Collins was getting at in his chapter in the Blackwell Companion to Natural Theology.

One counter-argument that could be raised to my analogy is that for all we know, the fence becomes blue over the horizon. Maybe it's blue from there on out, which means there could be far more blue than red. We just wouldn't know. If the blue represents the life-permitting range, then we'd have to say that maybe at some arbitrarily large or small value to some constant, the universe becomes life-permitting again.

Although it's possible, for all I know, that there could be islands of habitibility in the parameter space of all the constants, it strikes me as being unlikely that these islands would be very big if they exist at all. If we just limit ourselves to the known laws of physics and our ability to model, calculate, and simulate universes, as far as we are able to see, there are no remote pockets of habitility. If you just keep increasing or decreasing the value of some constant beyond the life-permitting range, the problem for habitility appears to only get worse. We can tell that without having to take it out to infinity. But admittedly, I don't know the physics well enough to press that point too hard.

For more thoughts on the normalizability objection see "The noramlizability objection to fine tuning, take one."

Stress testing your own apologetic

Do not despise prophecies, but test everything; hold fast what is good. ~1 Thessalonians 5:20-21

Let's say you want to design a super suit that will allow you to survive in outer space, under water, a burning building, and Antarctica in winter. You design it with materials you think can withstand high temperatures and low temperatures and maintain a constant pressure inside whether the pressure outside is higher or lower while keeping the occupant comfortable. You want it to be flexible so the person can move around in it. You want it to be strong so it doesn't rupture. You want it to be air tight while providing breathable air. And you want it to be able to maintain these properties through a wide range of temperatures and pressures.

Let's say you design and build this suit based on your knowledge of materials and the conditions under which you expect the suit will have to hold up. Once you've built it, how do you know it will work? Would you just assume the suit was good to go and allow somebody to take it out into the field? Would you happily put the suit on and walk through a burning building or jump into the ocean without having tested it? I suspect not.

Since you want it to keep people comfortable in space, you'd want to make sure it could do the job before somebody uses it for that purpose. You would want to test it. One way you might test it is by pressurizing it to see if there are any leaks. Since space is a vacuum, you want to make sure it can withstand a pressure differential of at least one atmosphere. What you would definitely not want to do is pressurize it half way and just assume it'll be good the whole way. In fact, you would probably want to raise the presurre inside to well beyond what you think is necessary. That gives you a margin of safety. If it can withstand a presurre differential of 10 atmospheres, then you'll feel much better about it's ability to work with a pressure differential of 1 atmosphere.

In other words, you want to stress test your suit. Before anybody steps into it, you want to see how far you can push the suit before it breaks. You want to come up with worst case scenarios to see how the suit holds up. The more rigorous the testing, the more confident you can be that the suit is safe to use. You test the suit by trying to make it fail. If it fails under testing, then you either abandon the design altogether or you attempt to improve upon the current design. Then you test it again. You keep doing that until the suit proves itself reliable under extreme conditions. Ideally, you want to make sure it's fully operational under conditions that are even worse than you think it will ever have to endure out in the field.

This is a procedure I think should apply, not just to super suits, but to your beliefs and your worldview as well. You don't want to believe something that's false. You want to believe what's true and right.

This procedure should apply to arguments as well. If you are designing a case for some point of view you want to promote in the public square, you don't want to just compile a random collection of arguments and start posting them on the internet. Instead, you should want to test them to see if they are good arguments. This applies whether we're talking about Christianity, politics, or any situation in which you hope to persuade another person of your point of view.

The first step in testing your case is to try to come up with counter-arguments. Look for holes or flaws in your own reasoning. Try to think of what it would take to falsify your point of view. Come up with the best objections you can think of. See if the arguments can withstand your own best attempt at refuting them.

You have to be honest with yourself in this process. If you were designing a super suit, of course you would want it to succeed. But it would be dangerous to go easy on the testing just so you don't have to watch it fail. In the same way, it would be reckless to "test" your case against what you know good and well are flimsy rebuttals. It would be reckless to test your case against an easily refutable strawman version of an objection. So you need to think of the best objections you can. If you know of some popular response to your argument, try to think of the best version of that response. If it's a weak response, then steel man it. Try to improve upon it.

This is how the scholastic philosophers like Anselm and Thoma Aquinas used to write. They would begin with an initial argument, then raise objections against it, then raise objections to those objections. They would continue this process, refining their view as they went along, until they finally arrived at a conclusion.

Modern analytic philosophers do something similar. A good example of that is in Alvin Plantinga's book, God, Freedom, and Evil. He spends several pages going back and forth trying to come up with a way to show an inconsistency between the theistic set containing the statements (1) God is all knowing, all powerful, and wholly good, and (2) Evil exists. He would raise some possible statement that when added to the theistic set would generate a formal contradiction. Then he would shoot that down and either adjust the statement or come up with another one. He continued this procedure until he ran out of ideas. In the end, he said that while the elusive proposition might yet exist, it would not be easy to find.

Once your case appears to hold up well under your own scrutiny, see how well it holds up against your friends' scrutiny. Somebody else who is on your side might be able to come up with objections you didn't think of. I used to be part of a private Christian apologetics group on Facebook many years ago. Most of them were pro-life, and I was, too. I wanted to test the pro-life case by having a devil's advocate debate. I took the pro-choice position and tried to come up with the best pro-choice case I could to see how the other person would respond. I hoped that he would be able to refute my arguments because I thought it would be a learning experience for me. It would enable me to improve my case for the pro-life position. I found a volunteer, and we had a formal mock debate.

I've had devil's advocate debates on debate.org, too. I do them partly as a learning experience, and partly for the fun of it. The good thing about defending a point of view opposed to your own is that it forces you to step in another person's shoes and try to see things from their perspective. It can be an effective way to gain a better understanding of their view than you might if you were just reading what they had to say, all the while raising objections to it in your head. Instead, you'd be reading what they had to say while thinking, "What are they actually trying to say?" and "How can I make this work?" You'd be reading for understanding rather than reading to respond, which often leads to misunderstanding.

In the past, I've called popular Christian apologists, philosophers, and scientists on their radio shows, sent them emails, or commented on their blog posts, raising objections to some talking point or argument I might agree with already to see how they would respond and hopefully learn from them.

Once you test your ideas under friendly fire, a third step would be to test them in the real world. This blog exists primarily for that reason. I express a lot of opinions on this blog in hopes of getting some interaction with people who are interested in the subject matter. I want to hear from people who disagree with me. I want them to push back. I also want to hear from people who agree with me in case they want to push back or tell me they think I'm on the right track. I also want to see how they will respond to my critics and how my critics will respond to them. I want different perspectives because I can't think of everything, and I don't know everything.

This blog used to get a lot more participation. I rarely get comments anymore, and I kind of feel like I'm talking to myself. This has caused me to sometimes be a little more risky about what I post. Yesterday, for example, I posted an argument for God I had just come up with. It's probably a flawed argument or somebody else would've already come up with it. But I didn't see the harm in posting it and offering my own initial thoughts on it. I included an objection I thought of, but I figured other people who knew more than I did might have something to say.

When I actually want to make a case for some point of view in order to persuade other people, I want to make sure I have the best case that I can have. I want to be able to articulate it in a way that's clear, easy to understand, and compelling. I don't want it littered with weak arguments. In sport debating, I might use weak arguments for filler or to waste the other person's time, but if I really want to persuade people, I only use what I personally think are the best arguments. They have to be arguments that I myself find persuasive. If I want to have a case like that, it has to be something I've tested against my own attempts to refute, against my team or tribe's ability to refute, against the objections raised by random people on the internet, and against the smartest people I can engage. If you ever want to write a book or an article, or if you want to pursuade your family or people you meet in the wild, I recommend testing your case first. Refine your apologetic by subjecting it to the fire of criticism.

Most people don't do that. Whether we're talking about Christian apologetics, abortion, climate change, gun control, or a host of public policy issues, most people simply look for anything that will confirm what they already believe. They're not interested in anything that might challenge their point of view. They're often dismissive. When I see people on line arguing with each other, I don't usually get the impression they're really listening to each other. I don't get the impression many people are interested in anything anybody else has to say. They treat each other with derision rather than curiosity. Sometimes, I think people avoid opposition out of fear and anxiety. If they are emotionally invested in their point of view, they don't want to find out that they're wrong. But I encourage you not to be afraid of the big bad critic. If you want to know the truth, it does you no good to simply seek to confirm what you already believe and avoid opposition. That would be like taking an untested super suit to Antarctica in the winter and hoping to survive.

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?