How strongly did Van Til feel about using TAG when arguing for God?
Now the only argument for an absolute God that holds water is a transcendental argument.
Quite strongly. It’s not that there aren’t other arguments – they just don’t hold any water when arguing for the kind of God revealed in the Bible – an absolute God. If we are totally dependent upon God (as is the case if God is absolute), then we are necessarily dependent upon God as our starting point in reasoning. If we aim to show that this kind of God exists, we must necessarily begin with this God (else he would not be the starting point in reasoning). But if we begin with this God, we must argue transcendentally for him, as any other method of argumentation will either never lead to him, or will be guilty of viciously circular reasoning.
But if it be said to such opponents of Christianity that unless there were an absolute God their own questions and doubts would have no meaning at all, there is no argument in return.
In other words, anti-theism presupposes theism. (For Van Til, “anti-theism” is any form of unbelief).
If God is our starting point in reasoning, then even the unbeliever must start with God if their argument were to operate from a consistent foundation. The unbeliever does not (vocally) start with God, and thus their inconsistency.
There lie the issues.
In other words, this is the issue with unbelieving thought. This is what we should be pressing in apologetics – that since God is the starting point in reasoning, then saying we don’t believe in him ultimately makes no sense. It is inconsistent with what must be the case in order for any activity (thinking, reasoning, predication, communicating, you name it) to ultimately have meaning.
It is the firm conviction of every epistemologically self-conscious Christian that no human being can utter a single syllable, whether in negation or in affirmation, unless it were for God’s existence.
Any argument of any form or purpose, even those which intend on showing God does not exist, must first presuppose that he does in order to be intelligible. This is exactly why the existence of the Christian God is a transcendental (a precondition). It is, in fact, why the existence of God is THE transcendental (the necessary precondition for the intelligibility of all human experience).
Furthermore, our job in Christian apologetics is to be “epistemologically self-conscious”, just because the unbeliever is not. It is our role to point out the inconsistencies between where the unbeliever “stands” (their unbelieving presuppositions), and everything they claim to know, every assertion they make, and every moral and aesthetic judgement they render, whether explicit or implicit.
Just as important as showing inconsistency is to show the arbitrariness of those unbelieving presuppositions. That is – even if those presuppositions were true, there were be no reason to believe they were true.
Finally, it is also crucial to show the consistency between where we stand (our Christian presuppositions), and what we claim to know, assert, and judge, as well as the non-arbitrariness of our beliefs. In other words, if the Christian worldview were true, then (and only then) there is reason to believe it is true.
When we do both of these things through a transcendental analysis, we have shown that God exists – we have used TAG.
Thus the transcendental argument seeks to discover what sort of foundations the house of human knowledge must have, in order to be what it is. It does not seek to find whether the house has a foundation, but it presupposes that it has one.
This is the reason to use TAG.
If your argumentation does not eventually lead back to God as the “transcendental” (that which makes any argumentation possible in the first place), then you have failed to establish the very foundation for your own argument that you claim is necessary for your opponent’s. While you may be operating from the true foundation of God’s word, you haven’t demonstrated that your foundation is any more solid than that of your opponent’s. While some (or many) opponents may be so taken aback by the strength of your internal critique of their worldview that they don’t get around to challenging yours, not every opponent will let you off the hook in this way.
If your argumentation does lead there, then you have argued TAG whether you know it or not.
All quotes from “A Survey of Christian Epistemology”
 – I use the qualifier “viciously” here for all reasoning about ultimate authorities/starting points is necessarily circular.
 – I use the qualifier “ultimately” here to for all experience must eventually be grounded in true, foundational presuppositions in order to make sense. While the assertion “All men are mortal” has “proximate” meaning (that is, we can understand what it means regardless of our basic presuppositions), it could not in principle make any sense unless the Christian’s presuppositions are true.