Can Rationality Come from Non-Rationality?
By Joel Settecase*
We had a guy come on recently—called himself "Random Guy." What followed was a perfect illustration of where the naturalistic worldview leads when it tries to account for reason, logic, and belief. It can’t. It can’t even begin to. Because if you're a naturalist, you have no rational grounds to trust your own reasoning.
This isn’t just a gotcha. It’s an inescapable implication of a worldview that says humans are just the product of time, chance, and chemistry.
Let’s walk through it.
Where Does Rationality Come From?
I started by pressing the issue: if you deny that God is necessary for intelligibility, then the beliefs you hold—formed by unguided, non-rational processes—are themselves non-rational.
He disagreed. So I made the distinction clear.
Beliefs are either rational or irrational. That’s not controversial. But if your beliefs arise entirely from a chain of chemical processes in your brain—unguided by any rational source—then those beliefs aren’t rational. They’re reactions.
I said it like this: if I poke your brain with a pen and that makes you think it’s cold, that’s not a rational inference—it’s stimulus and response. It's reflex. Now stretch that out: if everything happening in your brain is like that, you’ve got no reason to think your thoughts are aimed at truth. They’re just reactions. Brain fizz.
Can Rationality Come from Non-Rationality?
He tried to rescue the idea by saying that chemistry can produce rational thoughts. I pushed: how?
He didn’t offer a mechanism. Instead, he asked what would stop chemistry from being rational. But that reverses the burden. If you want to claim that non-rational processes produce rational beliefs, you’ve got to show how. Not just assert it.
So I gave the illustration again: shake a can of soda. It fizzes. You don’t call that fizz true or false. It’s just a chemical reaction. If your brain is just chemicals fizzing, why think your beliefs are any more rational than the soda?
Random Guy brought up medication as a counter-example. Some medications, he said, cause people to form certain thoughts. For example, ideation of self-harm. And since those thoughts exist, that must show that chemistry can produce ideas.
Sure. Chemistry can cause thoughts. But can it produce rational thoughts? That’s the real issue.
Can Something Be Logical but Not Rational?
Let’s get clear on categories. Not all thoughts are rational. A hallucination is a thought. So is a delusion. So is a fleeting, chemically induced emotional reaction. Those aren’t necessarily rational.
Rationality has to do with coherence, consistency, logic, and aiming at truth. If a thought arises without any guidance from truth-tracking processes—if it’s just a product of blind chemistry—why think it’s rational?
So I asked Random Guy to tell me how brain chemistry gives you logic. How it gives you inference. How it grounds the laws of reason. And he couldn’t.
Not because he wasn’t smart. But because naturalism just doesn’t have the categories.
Rationality Examples: God vs. Brain Chemistry
Here’s the contrast: I believe that our minds were created by a rational God. That we bear His image. That He embedded rationality in us because He is rational.
That’s why we can trust the processes of our mind—because they come from a trustworthy, rational source.
That’s why, in the Christian worldview, logic and reason make sense. They’re not random. They’re not arbitrary. They’re not borrowed from chaos. They’re gifts from God.
Colossians 2:3 says that in Christ "are hidden all the treasures of wisdom and knowledge." Proverbs 1:7 says, "The fear of the LORD is the beginning of knowledge."
You don’t get to reason toward God. You have to start with God or lose reason itself.
Is It Possible for a Human Being to Be Rational?
Random Guy wanted to say that maybe our brains just happen to work in rational ways. That maybe it just worked out that chemistry led to truth-tracking thoughts.
But that’s wishful thinking. You don’t get epistemological gold out of ontological sand. If the origin of your mind is irrational, chaotic, and purposeless, you have no basis for trusting it.
At best, you get a cosmic lucky guess. But even that “guess” is just brain fizz. It's not knowledge. It's not belief. It’s soda can theology.
The Christian doesn’t have that problem. We don’t guess at truth. We start with the One who knows everything—and who has revealed Himself. We reason because God is there, and because He made us capable of reason.
In the end, this isn’t just about logic or chemistry. It’s about sin.
The reason people deny God isn’t because of a lack of evidence. Romans 1 says God has made Himself known—plainly. The problem isn’t in the brain. It’s in the heart.
Sin causes us to suppress the truth. It causes us to cling to irrational explanations and pretend they’re rational. We try to ground reason in chaos because we’re running from the God who is Reason Himself.
But the good news is this: Jesus came to deal with that. He died to redeem not just our souls, but our minds. He rose to restore our ability to think clearly. To repent is to lay down irrationality and take up truth.
Romans 12:2 says, "Do not be conformed to this world, but be transformed by the renewing of your mind."
Here’s the stark truth: if naturalism is true, then your beliefs are just chemical reactions. Reflexes. Flashes. Fizz.
If Christianity is true, then your beliefs can actually be aimed at truth, because your mind was made by the God of truth.
So the next time someone tells you that reason can come from brain chemistry, ask them this: would you trust the fizz from a shaken soda can to tell you the truth about anything?
Then ask them why they trust their own brain.
*This article was written by ChatGPT based on a transcript from my debate, which I meticulously pored over. All the ideas are my own. To the extent that they are not, I disavow them. Watch the full debate stream here: https://www.youtube.com/watch?v=eF5DKrDqCI8.
Want to equip your church to stand firm and think clearly in a hostile world? Bring Joel in for a Defend Your Faith Weekend. Visit https://thethink.institute/forchurches to learn more and book today.