Are Multiple Logical Systems a Problem for TAG?

One of the things I love about doing online apologetics—whether on YouTube, in debates, or right here on this blog—is interacting with the wide range of objections people bring to the Christian worldview. Some are surface-level and easy to spot. Others are more technical and require careful thought.

Recently, I came across a particular challenge to presuppositional apologetics, specifically the transcendental argument for God’s existence (TAG). If you’ve followed my work, you know TAG is central to the presuppositional method. It argues that God is the necessary precondition for intelligibility—that logic, morality, science, and reason itself are only possible if the Triune God of Scripture exists.

This particular objection took aim at the claim that logic is absolute, universal, and immaterial, and that these features only make sense in a Christian worldview. But the critic I encountered had a different take—and I think it would be helpful to offer a response.

What the Critic Was Trying to Say

The objection had two main parts.

First, the critic claimed that using logic to critique logic isn’t necessarily self-refuting. The idea was that there’s a difference between using logic inside a system and analyzing logic from outside it. Philosophers call this meta-logic. So if someone says, “Logic is flawed,” they’re not necessarily contradicting themselves—they might just be examining logic as a subject from a higher level.

To use his own framing, it’s like talking about grammar in English—you’re using the language to critique the rules of the language. According to this line of thought, doing meta-logic isn’t self-defeating; it’s analytical.

Second, he argued that logic isn’t really absolute or fixed in the first place. He pointed to the wide variety of logical systems out there: classical logic, modal logic, fuzzy logic, relevance logic, paraconsistent logic, and so on. Each one defines key terms like identity, contradiction, and truth differently.

So the conclusion was: logic isn’t universal. It’s contextual. It’s just a toolset that humans create depending on the problems they want to solve. And if that’s the case, then it certainly isn’t grounded in the unchanging nature of God (This objection came from a professing Christian who disagrees with me on logic, presuppositionalism, and the transcendental argument for the existence of God).

A Closer Look at the Foundation

Now, I’ll be honest—this isn’t your typical "hating on presup" objection "Bro! So, you're saying the Bible is true because the bible is true!"

It's obviously a more thoughtful objection, and I appreciate that. Nevertheless, I do not think the objection lands.

Let’s start with the idea that using logic to critique logic is not self-defeating. That sounds clever, but it misses the bigger point. Even if you’re “stepping outside” one logical system to evaluate it, you’re still using logic to do the evaluating. You’re still assuming that propositions mean something, that contradictions matter, and that conclusions can follow from premises.

You can’t actually escape logic—you just shift the lens.

From a presuppositional standpoint, this is exactly the issue. It’s not about which logical system you’re using—it’s about the preconditions that make logic possible at all. Whether you’re reasoning within classical logic or doing meta-logic from above, you’re relying on order, coherence, and rationality. And none of those things can be grounded in a materialistic or relativistic worldview.

Different Logics Still Depend on Logic

Now, what about the second claim—that the existence of different logical systems shows logic is relative?

Again, at first glance, this seems compelling. But once you take a step back, it actually confirms the presuppositional point.

Yes, there are different logical systems. But all of them share certain foundational assumptions.

You simply can’t function logically—no matter the system—without basic categories like:

• Identity – A thing has to be what it is. Even fuzzy or modal logic assumes that a proposition has a stable referent.

• Non-contradiction – Even in paraconsistent logic, where some contradictions are allowed, those contradictions are carefully regulated. The system still draws lines.

• Inference – All logic depends on moving from one thought to another in a meaningful, non-arbitrary way.

• Distinction – If you’re going to define an alternative logic, you still need to distinguish terms, functions, and outcomes.

Let’s take a few quick examples.

• Classical logic says a proposition is either true or false—no middle ground.

• Modal logic deals with necessity and possibility (e.g., “It’s possible that A is true”).

• Fuzzy logic allows degrees of truth (e.g., “A is 0.6 true”).

• Paraconsistent logic tries to contain contradiction so it doesn’t explode into incoherence.

• Intuitionistic logic won’t let you say “A or not-A” unless you can actually prove one.

Yes, these systems handle things differently. But all of them assume that thinking means something. You still have propositions. You still have rules. You still have a framework of intelligibility. You still need logic to talk about logic.

And that’s the key. You can’t even describe or evaluate an alternative logic unless logic already exists.

Why the Christian Worldview Still Matters

Here’s why this matters for TAG and for presuppositional apologetics.

We’re not saying classical logic is “God’s logic” and everything else is false. That’s not the point. What we are saying is this: whatever logic you use—whatever system you adopt—you are still relying on principles that only make sense if the Christian worldview is true.

In other words:

• Logic is immaterial because God is spirit.

• Logic is unchanging because God is immutable.

• Logic is universal because God is sovereign over all minds and all creation.

The unbeliever wants to use logic without God. But the moment they make an argument, they’re assuming meaning, consistency, and rationality. They’re standing on the foundation they claim doesn’t exist.

Cornelius Van Til used to say, “The unbeliever has to sit in God’s lap to slap Him in the face.” And that’s exactly what’s happening here. The tools they’re using to critique the absoluteness of logic belong to the God they’re denying.

What This Looks Like in Real Conversations

Let’s bring this down to street-level apologetics.

You’re talking to someone online or in person, and they say, “Logic isn’t absolute. There are different logical systems.” You don’t have to launch into a lecture on Aristotle or modal operators. Just say something like:

“Okay, but aren’t you using logic to make that claim? How do you account for the fact that we’re even having a meaningful conversation right now—where terms have meaning, arguments have structure, and conclusions follow from premises?”

You don’t need to be an expert in symbolic logic. You just need to recognize when someone is borrowing capital from your worldview. They’re using tools that only make sense if Christianity is true—while trying to deny the very foundation that gives those tools their power.

And when you press these foundational questions—about the very possibility of logic, meaning, and truth—you’re not just poking holes in someone’s system. You’re calling them to recognize that they’re living in God’s world, using God’s gifts, while trying to explain everything apart from Him.

Conclusion

At the end of the day, logic is not an arbitrary convention, or relegated to non-transcendent conceptual schemes. It’s a reflection of the mind of God. The Logos—the divine Word through whom all things were made and by whom all things hold together (John 1:1–3).

When unbelievers reason, they testify to the God they suppress. Every argument they form, every conclusion they defend, is done using laws of thought that point to the character of the God who made them.

So the next time someone denies the transcendent and absolute nature of logic by appealing to multiple systems of logic, just ask the deeper question: What has to be true for any of this to make sense? And let that lead right back to the One who gives meaning to all things—our Lord Jesus Christ.

—Eli AyalaRevealed Apologetics

Disclaimer: This article was written using AI-assisted dictation. The content reflects my thoughts and voice as I dictated the material, and AI (ChatGPT) was used to transcribe and structure it for publication.