But I was new at all this and I was curious to see how effectively he could defend his god-belief. So I asked him to identify the first premise of his argument for God’s existence.
He replied: “Premise one: God exists.”
I then asked him how he established the truth of this initial premise.
He replied: “I presuppose its truth.”
I then explained that this does not move us from any perceptually self-evident fact to the conclusion that a god exists.
He replied: “God IS because he is presupposed...period.”
It was clear by this point that the person I was dealing with had some kind of psychological condition rather than a soberly considered philosophical viewpoint. By essentially saying “I presuppose it, therefore it’s true,” this fellow was signaling that he simply had a puffed-up estimation of his own cognitive faculties, perhaps deluded that they had been fortified by supernatural enhancement to conform reality to his wishes. I knew enough then not to expect honest debate with someone so afflicted with such a distorted sense of self. But given that this was one of my first impressions of presuppositional apologetics, I never forgot it.
Several years later I had occasion to discuss this with another apologist of the presuppositional persuasion. I explained that it remained stubbornly unclear just how the presuppositional argument, or “TAG,” was structured, beginning with its initial premise and proceeding to support its intended conclusion. I made sure to clarify that its intent is to conclude that the Christian god exists, and the apologist confirmed this. I then told him about the flamboyant fellow who insisted that “God exists” was his first premise and explained that this is not a logical way to support the conclusion, “Therefore, God exists.” The apologist did not express agreement with my contention, but offered the following by way of reply:
That God's existence is an inescapable presupposition does not mean that God's existence must be the premise. You could state the argument in two steps. One step would have God's existence as the premise, and then show that human knowledge is possible on that basis. The other step would be to begin with the negation of God's existence, and then show that human knowledge is not possible on that basis. But Van Til said that you can begin with any fact in the universe, such as "there is a tree in the yard" or "murder is wrong," and then show that such a statement is intelligible only if God exists.
Now, if you are wondering what exactly is the difference between a presupposition on the one hand, and a premise on the other, in terms of framing the structure of an argument, I’m right there with you. Perhaps by “presupposition” the apologist means an assumption that one takes for granted while a premise is that assumption made explicit. Or, perhaps “presupposition” is just another term for precondition. But presuppositions are epistemological while preconditions may be entirely metaphysical. For example, my heart beating is certainly a precondition of my ability to think, talk and act, but any my thinking does not per se presuppose my heartbeat as an epistemological premise. And your thinking and speaking does not presuppose my heartbeat either. You might not even know I exist! In other words, logically speaking, the truth of my statements does not depend in any noetically structural manner on the beating of my heart. If my statements are true, they are true regardless of whether or not my heart is beating. So I would exercise caution against confusing an epistemological premise with a metaphysical precondition. Yet I suspect it is the latter that the apologist had in mind here.
The first step described here is to start with “God’s existence as the premise, and then show that human knowledge is possible on that basis.” Presumably all parties already acknowledge that human knowledge is possible, but the way this step is stated seems to pin two burdens on the apologist: not only does he now have to show that a god exists (simply starting with that does not meet this burden), he now also needs to show that human knowledge is possible “on that basis.” Why not just focus on establishing the truth of the claim that there’s a god in the first place and worry about whether or not human knowledge is possible “on that basis” once the initial burden has been satisfied? It seems that this step is geared towards changing the subject, for now the focus will be on the nature of knowledge and its basis and not on how one can infer the existence of a god. The nature and basis of knowledge were not the original topics of inquiry.
Also, I suspect that whatever reasons the apologist might provide for supposing that knowledge is possible on the basis of his god’s existence, could be repackaged in terms of a rival belief, one which assumes the existence of something known to be imaginary, and have no less weight as a defense for that rival belief. The so-called “Fristianity” foil debated by some Vantillians as a possible counterexample to Christianity (Fristianity being similar to Christianity but with a four-headed god in place of Christianity’s triune god) is but one of possibly dozens of alternatives purporting to address fundamental questions about the nature of basis of knowledge. The point here is that once one opens the door to supernaturalism in order to explain some actual phenomenon in reality, we are limited not by facts but by whatever the imagination might invent. But knowledge is not imaginary, so neither can its basis be imaginary.
The alternative step – namely “to begin with the negation of God’s existence, and then show that human knowledge is not possible on that basis” – is no more promising than the first. Where the first step fails outright to establish the existence of said god and seeks to redirect our attention elsewhere, the second step misconstrues the nature of human cognition entirely. We do not begin by negating anything, but by perceiving and identifying what we perceive. Moreover, knowledge is not secured by rejecting arbitrary constructs and then affirming the validity of those constructs when we still find ourselves puzzled to explain something. Rather, we secure knowledge by discovering facts, identifying them by means of concepts and integrating them without contradiction into the rest of the sum of our knowledge.
This second step, if conducted by the apologist, will no doubt involve a string of pronouncements saying “this wouldn’t be possible” and “that wouldn’t be possible” all because his god is not “presupposed” at the head of the table, as it were. But such pronouncements would essentially assume the truth of what the apologist has been called to defend in the first place, namely the truth of his belief that his god is real. What he cannot show is that something we cannot perceive or verify by any objective means is preconditional to fundamental truths which are informed by facts which we can perceive. Moreover, what he cannot show is how one can draw the conclusion “God exists” from the objective starting point represented by the axiom ‘existence exists’. Indeed, if we begin with existence as our primary, what function would the god part perform? Blank out.
Which takes us to the apologist’s final statement: “Van Til said that you can begin with any fact in the universe… and then show that such a statement is intelligible only if God exists.”
So again, there is no actual argument here because what is presented is not a series of steps of an inference from something known to some new knowledge to which it logically leads, but rather a paradigm by which various aspects of the knowing process would be deliberately characterized in such a way as to compel an outcome of the god-of-the-gaps variety. From what I have seen, this is typically accomplished by asking a series of questions which are intended to evoke admissions of “I don’t know” from non-believers (“How do you know X?”), thus exposing some area of ignorance into which the believer can shoehorn his god-belief as the goo plugging the hole in the non-believer’s knowledge. The dirty little secret here, however, is that this magic goo is really nothing more than something we must imagine. The confirmation of this analysis would be secured by using the believer’s own “How do you know?” interrogation techniques against the paradigm itself. For the believer will only be able to give vague reasons purportedly necessitating aspects of the paradigm rather than step us through the epistemological stages of an objectively informed inference detailing an actual knowledge process which has rooted contact with reality from beginning to end.
I suspect, quite strongly in fact, that the typical believer going to prefer some apologetic route which keeps his own reasons for believing shrouded in mystery, not only from onlookers, but also from himself. He certainly would not want his own reasons for believing to be scrutinized, so we can expect him to keep them hidden from view. Also, it may very well be the case that he adopted his god-belief when he was a child, long before he ever learned about syllogisms, logic, fallacies, preconditions of knowledge, and any skills under the rubric of critical thinking. Admitting the fact that he’s been believing all these years essentially because it is a psychological habit which he has never allowed himself to examine critically, correct and outgrow, would only jeopardize his apologetic intentions. Presuppositionalism is ideally suited in this way to enable the believer to protect a philosophically indefensible commitment while conducting a pretentious offensive against outsiders who can, in the believer’s mind, never deserve straight answers about his faith.
by Dawson Bethrick