Thesis: the argument from reason mistakenly applies a general doubt about the validity of reason to the specific case of naturalism, but in reality applies equally to supernaturalism, as well as any other account of the universe, theistic or not. Therefore, it is not a relevant argument in discussions of theism.
TL;DR
The argument from reason states that naturalism (the view that only the natural exists and the supernatural does not) depends on reason, but makes it impossible to trust that same reason. On this grounds, it rejects naturalism. However, it is impossible to trust reason under any worldview, including theism. This has nothing to do with naturalism - it's just a feature of reason. Therefore, the argument from reason, if successful, succeeds at rejecting all worldviews (including the claim that the argument from reason itself is valid). So the argument from reason contradicts itself and must fail.
The Argument from Reason
The argument from reason is an argument associated with Christian apologist C. S. Lewis and popular with online Christian apologists in general (though it does not relate to Christianity specifically). The argument seeks to disprove a view of the universe called "naturalism", which basically holds that only natural things and the relationships between them exist, and that the supernatural doesn't. Some versions of the argument also further try to prove supernaturalism or theism.
Here is C. S. Lewis's description of the argument from reason:
One absolutely central inconsistency ruins [the naturalistic worldview].... The whole picture professes to depend on inferences from observed facts. Unless inference is valid, the whole picture disappears.... [U]nless Reason is an absolute--all is in ruins. Yet those who ask me to believe this world picture also ask me to believe that Reason is simply the unforeseen and unintended by-product of mindless matter at one stage of its endless and aimless becoming. Here is flat contradiction. They ask me at the same moment to accept a conclusion and to discredit the only testimony on which that conclusion can be based.— C. S. Lewis, "Is Theology Poetry?", The Weight of Glory and Other Addresses
In simpler terms, the argument basically goes like this:
If we claim naturalism is true, then we and everything we are is the result of natural, mindless, non-rational forces acting without any purpose.
If we are the result of nonrational forces, there is no reason to think that they would produce humans with an ability to use reliable reason.
Therefore, we have no reason to trust our own reasoning, and so we can't trust the reasoning that led us to naturalism.
A common counterargument to this is to point to evolution.
Evolution, the defender of natural logic will say, favors humans who can correctly reason over those they cannot! Therefore there is a reason to think mindless forces produced reliable reason in us! It is at this point the proponent of the argument from reason will usually smirk, and say, "Oh? And how exactly do you know evolution is true? Did you use reason to conclude that? Hohohoho!", pushing up their glasses as they gently stroke their signed copy of Mere Christianity.
The apologist's defense here is simple but quite impenetrable. Any counterargument you present to defend your naturally-created reason will be based on, you guessed it, reason. So any counterargument you make will be circular! You cannot use unreliable reason to show that same reason to be reliable!
The apologist's defense here is simple but quite impenetrable. Any counterargument you present to defend your naturally-created reason will be based on, you guessed it, reason. So any counterargument you make will be circular! You cannot use unreliable reason to show that same reason to be reliable!
But they forget that in a naturalistic worldview, everything is the result of matter acting in accordance with the physical laws. Not the laws of logic. So, when the atheist cites "reason" or a "reasonable conclusion", it really just the result of an unintelligent, mindless, material process that follows the physical laws, not logic/reason.
But what of the Theist? She is not bound by the natural or by the physical laws. Thus, that which constrains the atheist/naturalist brain does not do so to the Theist. The Theist is free from the bounds of the physical and can engage in critical thinking as governed by the laws of logic. - From my post on the Argument From Reason
So, what are we to do? Do we give up and convert to theism post-haste? Instead, let's take a trip - in our favorite rocket ship - to visit Planet Populon.
Planet Populon
Planet Populon is a distant planet not so different from Earth. On it live a race on beings called the Popularians, who are little purple creatures with four arms and six toes on each foot. They are very similar to humans, save for one important difference: they are incapable of understanding the logical fallacy of appeal to popularity.
The appeal to popularity is a simple logical fallacy that says "because an idea is popular, it must be true." To us humans, it's easy to see why this is false. For example, it was once popular to think the earth was flat! In some places, it's popular to think that pineapple tastes good on pizza! And yet those things are obviously false.
But the Popularians are different from us. They are incapable of recognizing this as a fallacy. Whenever one of them begins to think about the problems or contradictions that arise from an appeal to popularity, a special gland in their brains immediately floods their minds with thoughts of the last sports-ball match they watched, and they stop thinking about logical fallacies. Thus, the Popularians never realize that an appeal to popularity is fallacious - they are convinced that it's a valid form of reasoning.
The Popularians, too, believe in God. In fact, they have a logical proof of God's existence, known as the populogical argument. It goes a little something like this: most Popularians believe God exists – therefore, God exists. It's a flawless argument, beautiful in its simplicity, so elegant and minimal that there's no room for logical errors to possibly slip in. Furthermore, for those crazies that question whether reason itself is valid, the Popularians have an answer! It's popular to think that if God exists, he would create the Popularians with reliable reason. And since it's popular, it must be true! So the Popularians' reason must be reliable.
But we, from the side, know there is an error in the populogical argument. The argument commits a logical fallacy - an appeal to popularity. This means the Popularians' reason is not reliable, God or no. But the very fact that their reasoning is unreliable makes them unable to find the flaws in their proofs of their reasoning being reliable!
The Point
So what's the point of our visit to Planet Populon? It's simple. How do we know we are not like the Popularians?
If our reason was unreliable, and there was some fallacy we were incapable of noticing or some rule of logic we were missing, then all of our arguments would be moot. No matter how hard we worked to prove that the sky is blue, or that God exists, or that our reasoning was reliable, it would be pointless, because the very reason we used to tell the good arguments from the bad would be misfiring. And there's no way to prove we'd know if this was the case - after all, to prove that, we need to assume reason is reliable in our proof! It is impossible to prove that reason is reliable, because you need to use reason to do so.
So what does this have to do with the argument from reason? Well remember, the argument from reason was an argument targeted at naturalism. It said that naturalism must be false, because it implies our reason can't be trusted. But the Popularians don't believe in naturalism, and their reasoning still can't be trusted! It turns out, you can never prove your reason is trustworthy. No matter your worldview, you must assume your reason is reliable in order to make any argument at all.
Planet Populon
Planet Populon is a distant planet not so different from Earth. On it live a race on beings called the Popularians, who are little purple creatures with four arms and six toes on each foot. They are very similar to humans, save for one important difference: they are incapable of understanding the logical fallacy of appeal to popularity.
The appeal to popularity is a simple logical fallacy that says "because an idea is popular, it must be true." To us humans, it's easy to see why this is false. For example, it was once popular to think the earth was flat! In some places, it's popular to think that pineapple tastes good on pizza! And yet those things are obviously false.
But the Popularians are different from us. They are incapable of recognizing this as a fallacy. Whenever one of them begins to think about the problems or contradictions that arise from an appeal to popularity, a special gland in their brains immediately floods their minds with thoughts of the last sports-ball match they watched, and they stop thinking about logical fallacies. Thus, the Popularians never realize that an appeal to popularity is fallacious - they are convinced that it's a valid form of reasoning.
The Popularians, too, believe in God. In fact, they have a logical proof of God's existence, known as the populogical argument. It goes a little something like this: most Popularians believe God exists – therefore, God exists. It's a flawless argument, beautiful in its simplicity, so elegant and minimal that there's no room for logical errors to possibly slip in. Furthermore, for those crazies that question whether reason itself is valid, the Popularians have an answer! It's popular to think that if God exists, he would create the Popularians with reliable reason. And since it's popular, it must be true! So the Popularians' reason must be reliable.
But we, from the side, know there is an error in the populogical argument. The argument commits a logical fallacy - an appeal to popularity. This means the Popularians' reason is not reliable, God or no. But the very fact that their reasoning is unreliable makes them unable to find the flaws in their proofs of their reasoning being reliable!
The Point
So what's the point of our visit to Planet Populon? It's simple. How do we know we are not like the Popularians?
If our reason was unreliable, and there was some fallacy we were incapable of noticing or some rule of logic we were missing, then all of our arguments would be moot. No matter how hard we worked to prove that the sky is blue, or that God exists, or that our reasoning was reliable, it would be pointless, because the very reason we used to tell the good arguments from the bad would be misfiring. And there's no way to prove we'd know if this was the case - after all, to prove that, we need to assume reason is reliable in our proof! It is impossible to prove that reason is reliable, because you need to use reason to do so.
So what does this have to do with the argument from reason? Well remember, the argument from reason was an argument targeted at naturalism. It said that naturalism must be false, because it implies our reason can't be trusted. But the Popularians don't believe in naturalism, and their reasoning still can't be trusted! It turns out, you can never prove your reason is trustworthy. No matter your worldview, you must assume your reason is reliable in order to make any argument at all.
This is the flaw! The argument from reason doesn't say that "reason is unreliable", it states that "reason is unreliable under a naturalistic worldview". And that's because a naturalistic brain is constrained by the physical laws. Every human action, including thoughts, is the result of the physical laws. The laws of logic play zero part in the thinking process.
This means that the argument from reason succeeds not just against naturalism, but against any worldview! For example, here's the argument again, but directed at theism this time.
If we claim theism is true, then we and everything we are is the result of supernatural, mindful, rational forces acting without any purpose.
This means that the argument from reason succeeds not just against naturalism, but against any worldview! For example, here's the argument again, but directed at theism this time.
If we claim theism is true, then we and everything we are is the result of supernatural, mindful, rational forces acting without any purpose.
Strawman argument - a logical fallacy where someone misrepresents, exaggerates, or distorts an opponent's actual argument to make it easier to attack, creating a weak "straw man" version to knock down instead of the real, stronger position, thereby appearing to win the debate without addressing the core issue. It's a deceptive tactic in debates, often involving oversimplification or taking words out of context, to make one's own stance seem superior.
I do not argue, nor do I know of any Christian who argues for a "supernatural, mindful, rational forces acting without any purpose"
If we are the result of rational forces, there is no reason to think that they would produce humans with an ability to use reliable reason.
Therefore, we have no reason to trust our own reasoning, and so we can't trust the reasoning that led us to theism.
If we are the result of rational forces, there is no reason to think that they would produce humans with an ability to use reliable reason.
Therefore, we have no reason to trust our own reasoning, and so we can't trust the reasoning that led us to theism.
A theist might object and say, "of course we have reason to think rational forces would produce rational minds!" But this time we can smirk, push up our glasses, and say, "Oh? And how exactly do you know rational forces would produce rational minds? Did you use reason to conclude that?" Once again, any argument you use to show that human reason is reliable under theism is itself based on that same reason
A theist might object and say, "of course we have reason to think rational forces would produce rational minds!" But this time we can smirk, push up our glasses, and say, "Oh? And how exactly do you know rational forces would produce rational minds? Did you use reason to conclude that?" Once again, any argument you use to show that human reason is reliable under theism is itself based on that same reason.
Notice a parallel here. It's quite reasonable to think that we can trust our reason under theism - after all, we can propose a simple mechanism for it (God made it that way). Just as before, it was quite reasonable to think that we can trust our reason under naturalism - after all, we can propose a simple mechanism for it (evolution made it that way). But in both cases, establishing these mechanisms relies on our reason, so ends up being circular.
Notice a parallel here. It's quite reasonable to think that we can trust our reason under theism - after all, we can propose a simple mechanism for it (God made it that way). Just as before, it was quite reasonable to think that we can trust our reason under naturalism - after all, we can propose a simple mechanism for it (evolution made it that way). But in both cases, establishing these mechanisms relies on our reason, so ends up being circular.
Under a theistic worldview, human reasoning is not viewed as a mere evolutionary byproduct for survival but as a reflection of a divine mind.
In this framework, the ability to think logically is often treated as a "gift" or an "imprint" of the Creator, ensuring that the human mind is attuned to the structure of the universe. This perspective changes why we trust our thoughts and how we use them.
The central premise of theistic reasoning (particularly in the Abrahamic traditions) is the concept of Imago Dei—that humans are created in the "image of God."
Since God is viewed as the ultimate rational being (the Logos), creating humans in His image implies endowing them with a "spark" of that rationality. This gives humans the unique ability to step beyond instinct (like animals) and engage in abstract thought, mathematics, and moral judgment. We reason because we are "mini-reasoners" modeled after the "Great Reasoner."
In a theistic worldview, the laws of logic (like A cannot be non-A) are not arbitrary rules invented by humans, nor are they rules that God simply "decided" to create. Instead, they are believed to be reflections of God's own nature.
Because God is consistent and cannot lie or contradict Himself, the universe He created operates on consistent, non-contradictory laws. When humans use logic, they are not inventing a tool; they are discovering the fabric of reality. To reason correctly is to think God's thoughts after Him.
Since a rational God designed the human mind specifically to know and understand the world, then we have a valid reason to trust our cognitive faculties. We can assume that our logic maps onto reality because both were made by the same Author.
Contrary to the popular cultural idea that faith and reason are opposites, the classical theistic view (championed by figures like Thomas Aquinas and Augustine) sees them as partners. It's actually atheism/naturalism v reason that are opposites, or incompatible.
"Faith Seeking Understanding": This famous Latin phrase (fides quaerens intellectum) suggests that faith is the starting point that orients the mind, while reason is the tool used to explore and understand that faith.
Theists often describe two sources of knowledge:
The Book of Scripture: Specific revelation (moral laws, nature of God).
The Book of Nature: General revelation (science, physics, logic). Since both books have the same Author, theists believe they cannot ultimately contradict each other. If they seem to, it is presumed that our human interpretation of one (or both) is wrong.
Theistic worldviews also offer an explanation for why human reasoning fails (bias, error, delusion). This is often called the "noetic effect of sin" or human finitude.
While the capacity for reason is divine, the execution is flawed because humans are imperfect/fallen.
Summary: The Difference
| Feature | Naturalistic View | Theistic View |
| Origin of Reason | Evolutionary adaptation for survival. | Imprint of the Divine Mind (Imago Dei). |
| Basis of Logic | None.Thoughts are the result of physical laws not logical laws.. | Reflection of God's internal consistency. |
| Why Trust It? | Can't as it works for survival, not truth seeking | It was designed to find Truth. |
| Goal | To adapt and survive. Logic/truth not relevant | To know God and understand His creation/reality. |
Only axiom is Reason is the basis for knowledge
Conclusion
The argument from reason is too successful. It's an example of a class of arguments I've witnessed more and more in recent years, that I call "sinking canoe" arguments. The name comes from the following story:
The argument from reason is too successful vs atheism/natursalism, not Christain theism.
Two men are sitting in a canoe. Suddenly, a leak springs in the bottom of the canoe, and it begins to fill with water. The man in the back stands up, walks to the front, carefully examines the other man's seat, and declares: "Yep! Your half is sinking!"
The format of the fallacy is much like the argument from reason. Let's say you believe in idea A, and want to refute some competing idea B. Take a general issue that plagues both A and B, change up some wording and introduce some terminology to make it seem specific to B, and then present it as a refutation of B. These arguments are so very effective because to refute the specific argument against B usually seems impossible, because it's not an argument against B at all. What really must be done is to see the argument for what it is: a general issue that rests on a deeper level than the contest between A and B, and that supports them both – an issue that must be resolved before either A or B can succeed, or must refute them both, but that offers no insight into which of A or B is the better idea. The canoe sinks for us both, and we must either patch it together, or both go down with the ship.
Sorry to tell you, but we are not sitting in the same boat. Since your naturalism cannot account for or give grounding to reason, critical thinking, or logic. However God can.
So yes, your boat is sunk, not the Christian's!
The Argument from Reason
