TAG: Why You Can’t Think Without God
Most arguments for God try to slowly work their way up to Him. TAG does the opposite. It shows that you can’t even start thinking unless God already exists. Logic? You got it from God. Morals? From God. Science? Also from God. Even the atheist who argues against God has to borrow from Him just to make the argument.
Once you see this, you can’t unsee it.
In parts one and two of this series we discussed TAG in passing but let us now take a deeper look.
1. What Is TAG? (Simple Version)
TAG stands for the Transcendental Argument for God.
That sounds complicated, but here’s all it means:
Without God, nothing else makes sense.
Not logic.
Not science.
Not morality.
Not knowledge.
Not truth.
Not even arguments.
Everything you use to think, learn, or make decisions needs God behind it to make sense of it.
2. A Little Background (No Philosophy Degree Needed)
Cornelius Van Til
He’s the guy who summarized TAG with this mic-drop line:
“Atheism presupposes theism.”
Translation: the atheist needs God just to argue against God.
Greg Bahnsen
He explained TAG in debates and showed how every non-Christian worldview eventually collapses.
Immanuel Kant
Not a Christian, but he pointed out that you can’t have knowledge unless certain things are already true.
Van Til said: “Exactly — and God is the ultimate thing that must be true.”
3. The Bible Actually Teaches This
TAG is not just philosophy — it’s biblical.
Colossians 2:3 — In Christ are hidden all treasures of wisdom and knowledge.
Proverbs 1:7 — The fear of the Lord is the beginning of knowledge.
Romans 1:18–21 — Everyone already knows God exists, but unbelievers suppress the truth.
So Scripture says:
You start with God,
not try to reason to God.
4. God and Logic (Why Math and Arguments Need God)
Lots of people think logic is something humans created. Not true.
TAG says:
God didn’t invent logic as a tool.
Logic reflects the mind of God.
God is perfectly rational, consistent, and truthful.
So when people use logic, they’re actually using something grounded in God’s nature.
5. How We Know Anything (Revelational Epistemology)
Fancy phrase, simple meaning:
We can know things because God reveals truth.
Without God:
How would you know your mind is reliable?
Why would logic work?
Why would nature act the same tomorrow as today?
Why would “right” and “wrong” mean anything?
Atheism can’t explain any of these.
Christianity explains all of them.
6. The Problem with Unbelief
The Bible calls the unbeliever a “fool.” Not an insult — it means:
Someone who can think, but can’t justify their thinking. Someone who can see the evidence for God everywhere but still do not believe.
They know things.
But they can’t explain how knowledge is possible in their worldview.
It’s like having WiFi but no router. You are getting internet access but cannot explain why or where it comes from.
They use logic, science, and morality, but their worldview provides no foundation for those things.
7. “Atheism Presupposes Christian Theism”
This means:
The atheist uses logic → which only works because the God of the bible exists.
The atheist trusts science → which only works because the God of the bible makes nature orderly.
The atheist makes moral claims → which only work because the God of the bible is holy.
Every worldview except Christianity eventually breaks apart.
Christianity alone can explain:
why reality is rational,
why truth exists,
why logic doesn’t change,
why science works,
why morality is real.
8. The Slap Analogy
Van Til gave this legendary illustration:
A child sits on her father’s lap so she can slap him.
She can only slap him because he’s supporting her.
Same with atheism:
They sit on God’s lap (using logic, order, morality)
Then use those things to argue against the God who gave them.
They have to borrow from Christianity just to reject Christianity.
9. Why TAG Is So Strong
TAG isn’t powerful because Christians are smart.
It’s powerful because the Bible is true.
Once someone ditches Scripture as the final authority, everything starts falling apart — miracles, the resurrection, the atonement, all of it.
TAG protects the foundation.
10. The Impossibility of the Contrary
TAG doesn’t say:
“God is probably real,”
or“God is the best explanation.”
It says something way stronger:
Without the Christian God, nothing can be explained at all.
No God → no logic, no knowledge, no truth, no science, no morality.
Christianity is true because everything else fails if you try to remove God.
This is TAG in one sentence: