What Is TAG, the Transcendental Argument for God? (Advanced Guide)

By Joel Settecase / June 8, 2023

The following article is adapted from my book, The Doctrine Shapes the Defense: The Importance of the Trinity in John Frame’s Apologetics. If you want to read this book, you can find it on Amazon for a few dollars.

The Transcendental Argument for God was first developed by Cornelius Van Til, the godfather of Presuppositional Apologetics. Since Van Til first articulated it, it has been picked up and worked on by subsequent theologians and apologists. Prominent among them has been John M. Frame. 

Frame’s apologetics is shaped by trinitarian theology. His approach involves Transcendental argumentation for God (TAG), as well as the use of evidences and psychological appeals. 

How Does the Transcendental Argument for God Work?

TAG proves God’s truth by assembling Biblical presuppositions and reasoning, in order to demonstrate the impossibility of the contrary. Such argumentation is three-fold, or to use Frame’s own term, triperspectival. 

Appeal to law and scripture (the first, or “normative” perspective, cf. Jesus’ own apologetic reasoning with the Scribes and Pharisees and the Apostle Paul in Acts 17). Argue from the facts about the world (the second, or “situational,” perspective). And appeal to the whole person (the third, or “existential” perspective). Just as it is impossible for anything to make sense without God (theism), it is likewise impossible to make sense of the world without the biblical God (Trinity). 

TAG involves two steps, followed by a third step. 

  • STEP 1: Both parties assume the unbeliever’s point of view for the sake of argument. Do a reductio to demonstrate the absurdity of the unbelief. Really you’re just telling the unbeliever how his views look to you as a Christian (John Frame, Doctrine of the Knowledge of God, Phillipsburg: P&R Publishing, 1987, 359). 

  • STEP 2: Ask the unbeliever to assume your position for the sake of argument. Attempt a reductio, which is impossible. Demonstrate that the Christian worldview is the only one that makes sense. In this process, do not pretend that there is any “neutral ground” between the Christian and non-Christian positions, because there isn’t. The unbelieving position is absurd, so trying to bring Christianity over to the unbelieving side in any way—perhaps in an appeal to “bare facts”—would make Christianity similarly absurd. 

This becomes difficult because of the desire to be accepted. This feeling can tempt the apologist to desire to give up too much. In fact, apologists have historically gone too far. John Frame cites Justin Martyr as an example from the ancient world, but there are plenty of examples today (Frame, A History of Western Philosophy and Theology, Phillipsburg: P&R, 2015), 90–91).  

It is important for the apologist to present the truth uncompromisingly, in order that the non-Christian may, by God’s grace, realize it and repent. Thus the apologist moves to the third step: 

  • STEP 3: Plead with the unbeliever to accept Christ as Savior from the sin of autonomy. 

TAG and the Impossibility of Non-Christian Positions

TAG takes seriously the biblical obligation to presuppose revelation and address unbelieving suppression of the truth (Romans 1:18–22). The apologist uses indirect (or direct, says Frame) argumentation to show that the non-Christian alternative is impossible. The apologist, arguing transcendentally, understands that the goal of apologetics is to convince people that the triune God’s revelation is true, and the criterion for truth. 

God is not just the conclusion of the argument but the one who makes the argument possible.

The way that Frame uses TAG is triperspectival. It and defends the truth of the triune God (the normative perspective), undercuts and disproves all unbelieving worldviews (the situational perspective), and invites the unbeliever to repent and trust in Jesus (the existential perspective), appealing in a compelling way to the unbeliever’s reason, experience and emotions. 

The apologist is to build on the strengths of his opponent’s views and show how only the correct view will satisfy the unbeliever’s desire. 

Unbelief As a Religious Choice

According to the Bible the unbeliever, after all, is suppressing the truth. He is presupposing both God and not-God. They know God, and they do not know God (DKG, 50). 

Unbelievers make a religious choice to deny God. For instance, presupposing naturalistic evolution, because the only alternative is Biblical creationism, is a religious choice (DKG, 186).

So how does the unbeliever both know and not know God?  Everyone knows God in one of two ways. For the unbeliever, there are certain truths about God that are self-evident from God’s revelation. For the Christian, however, knowledge of God is “servant-knowledge,” that is, knowledge about God as Lord and a knowledge that is subject to God as Lord. 

The unbeliever has enough God-knowledge to be without excuse. Many Christians today talk about Christianity as being about a relationship with God, but Christians are not the only ones who have a relationship with God. Unbelievers lack love for God, yet they are involved with Him (they have a “relationship” with Him) as an enemy. Their response is irrational. Their disobedience is tantamount to lying. They fight against the truth. They affirm falsehoods, living as practical atheists. Their unbelief leads to holding conflicting beliefs. Their epistemology is affected—they cannot reason correctly. Therefore lies often dominate over truth (which must be the opposite of the case for the Christian). Their efforts are self-frustrating, because it’s impossible to destroy truth and establish a false god (DKG, 59). 

Attempting to avoid a crazy state of affairs—a nonsensical world of facts—the unbeliever steals from the Christian worldview. Without acknowledging the triune God, they trust that unity and diversity, laws and facts, etc., obtain and are intelligible. Yet while stealing from Christianity, they reject the true God and pursue impossible autonomy. TAG reveals this.

TAG As An Evangelistic Tool

The Christian is in a unique position to help the unbeliever, because unbelieving thought systems always point away from the biblical truth of God that is behind all reality. Something vital is always left out in the unbeliever’s concept of God, making his concept of God an idol. Idols cannot satisfy or give eternal life; only God can. Christians know the God who is truth, viz. Jesus Christ (Jn 14:6). By utilizing the Transcendental Argument and process detailed above, we are able to see—and point out—what is missing from other worldviews. Using TAG, the Christian apologist conveys nothing less than God himself to the unbeliever and offers God’s own wholeness and new life. 


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