Notes from Summary of Transcendental Arguments lecture from Greg Bahnsen:
Take p (feature of human experience) and show q is the precondition of p. Q is necessary to explain the possibility of P. Not that Q is deduced or induced from P , but Q is the necessary presupposition of P. Q is the Christian worldview. Take any aspect of human experience and show that if Christianity is not true, you wouldn’t be able to show that P is possible. How do we demonstrate that?
Not Q (Christian Worldview) implies an absurdity or renders the operational feature impossible. If you deny the Christian worldview, it would imply an absurdity or contradict P which is undoubted. When we argue, we start with something that is not doubted. When we argue with someone, we start with something that he doesn’t doubt. Take what is some undoubted operational feature and show that if you deny the Christian worldview, you either have an absurdity or you are led to contradict the P which you didn’t have any doubt about or you render the operational feature that you’re talking about (scientific methodology, abstract objects), you render that feature impossible. Ask the unbeliever what are they willing to assert, from that show that the Christian worldview if denied, that operational feature is either impossible or the P that you’ve taken for granted is in fact false. You take the opposite position and show that it creates this intellectual difficulty.
Take P and show that it implies Q and show that the denial of P implies Q as well. We can take the opposite of P and show that it shows that God exists too. What if P is “God exist?” and not-P is “God doesn’t exist?” If God exists then that implies that God exists. If you argue that God does not exist that also implies that God exists. Take any experience and any point of view, even the atheistic point of view, to argue that point you have presupposed the existence of God.
The transcendental method is useful on either interpretation of transcendental argument:
Conceptually, if you wish to argue at all, then you must presuppose the existence of the Christian worldview to make sense of your own argument. The “must” is a psychological interpretation. If you want to make sense of your reason you must psychologically presuppose the Christian worldview.
The Existential interpretation says if you want to give an account of your ability to know anything, then your explanation must presuppose truth of the Christian worldview. The “must” here isn’t psychological (you can’t escape thinking about the Christian God when you argue). The explanation must include a reference to the Christian worldview.