by John M. Frame
Professor of Systematic Theology and Philosophy
Reformed Theological Seminary, Orlando, FL
My thanks to Don Collett for his careful thinking on the important issue of transcendental argument. He has stated my position accurately and has presented some criticisms of my argument that are well worth further reflection. I’m also grateful to him for defending me against certain points made by Bahnsen and Craig.
The formal analysis of presupposition by Strawson and Van Fraassen is a helpful addition to our discussion of these matters. Certainly I agree that Strawson’s formulation expresses accurately what Van Til usually meant by presupposition. So, as Collett puts it, if (say) causality presupposes God, then either the affirmation or the denial of causality implies God’s existence. This is the analogue to modus ponens. And, in the analogy to modus tollens, if God does not exist, then the existence of causality can neither be affirmed or denied, for on that assumption causality is not an intelligible concept.
I also agree with Collett that this definition of presupposition enables apologists to construct some non-traditional argument forms. Following Van Fraassen, He proposes the following argument form (certainly in an actual discussion it would have to be filled out by additional premises and definitions):
Causality presupposes God.
There is no causality.
Therefore God exists.
This is not the traditional modus ponens, since the second premise denies the antecedent of the first, though it may be described as an “analogue” of modus ponens. But given the definition of presupposes it is a valid argument. Similarly with Collett’s analogue of modus tollens:
Causality presupposes God.
There is no God.
Therefore, causality is unintelligible.
It will be interesting to see how Collett and others make use of these argument forms, developing formulations of them for practical debate.
I will, therefore, no longer claim that presuppositional argument is the same thing as traditional implication. I will, however, continue to claim that one may reach presuppositional conclusions by traditional argument forms, as well as the Collett-Van Fraassen form.
Presuppositional apologists have regularly used these traditional forms to establish the presupposition of Christian theism. In his taped debate with Gordon Stein, for example, Greg Bahnsen (whom Collett quotes as agreeing with him on the distinctiveness of presuppositional argumentation) argued that those who deny Christian theism can give no adequate account of logic, natural law, or morality. That is to say, he argued “logic, natural law, and morality, therefore God.” Van Til himself and other disciples including myself have argued in the same way. This is a straight modus ponens argument, not essentially different in this respect from arguments used by Thomas Aquinas and other traditional apologists.
Now, to those of us Van Tillians who use such arguments, the relation between (say) logic and God is more than mere implication. We believe not only that logic implies God, but that logic presupposes God in the Strawsonian sense. How then can we move beyond mere implication, to argue that God is the presupposition of logic? One way is simply to draw out further implications. Start with Bahnsen’s argument that logic implies God’s existence. Then argue that without logic, no predication is possible. Then we can use something like this syllogism: If predication is possible, then logic is reliable. If logic is reliable, then God exists. Therefore, if predication is possible, God exists. This syllogism shows (in very summary fashion, of course) that without God neither logic nor anything else is intelligible, a transcendental conclusion.
From that conclusion we may further deduce that God is the presupposition of logic in the Strawsonian sense. For if the intelligibility of logic depends on God, then either the affirmation or the (intelligible) denial of the reliability of logic1 entails God. And (as in Collett’s modus tollens analogue) if God doesn’t exist, then logic is not intelligible; so neither its reliability nor its non-reliability may be affirmed.
This reasoning can be summarized in a modus ponens argument: If predication, then God; predication; therefore God. The syllogisms in #3 and #4 above are also in traditional argument forms. So this argument does not require a distinctive argument form. It uses common argument forms that have often been used by traditional apologists. So it is possible to deduce a transcendental conclusion by means of traditional argument forms.
I would suggest that this is a general pattern in the apologetic tradition. When Thomas Aquinas argues that God is the first cause of everything, “everything” certainly includes the intelligibility of the world, the possibility of predication. Similarly, many apologists have argued from traditional arguments to transcendental conclusions.
At this point, someone will object that no, Aquinas’s argument is not transcendental, because he begins by assuming that causality (say) is intelligible apart from God. But how do we know that that is what he assumes? Certainly he doesn’t say that.2 Why should we not give him the benefit of the doubt, namely that his argument expresses his conviction that without God nothing is intelligible? When Bahnsen argues “logic, therefore God” as above, we give him that benefit of the doubt. Why should we not also give it to Aquinas?
We find ourselves at this point trying to read Aquinas’s mind and heart. This is the source of my phrase “presuppositionalism of the heart.” The same argument (such as Aquinas’s causal argument) can be used by someone who believes, and by someone who does not believe, that the intelligibility of causality presupposes God. Let’s say that apologist A thinks that causality is intelligible without God, but that it can be a means of proving God’s existence. Apologist B, however, thinks that causality is not intelligible without God, and he seeks to show that by a causal argument. Apologist A and apologist B, however, may use precisely the same argument.3 How, then, do we know when an apologist is or is not reasoning transcendentally? Sometimes (as with Bahnsen) through an apologist’s own testimony. Other times (as with Aquinas) we just have to guess. My only plea is that when we are guessing, we should give to the apologist the benefit of the doubt.
Nothing in Collett’s paper persuades me that what I’ve done above is illegitimate, i.e. using traditional argumentation to reach a transcendental conclusion. Collett, indeed, may well agree with me.4 His point is not that traditional argument forms are incapable of reaching transcendental conclusions, but rather that in addition to these we may also use the Van Fraassen forms. I welcome this addition to our apologetic arsenal. I still maintain, however, that when an apologist uses traditional modus ponens or modus tollens it is not always possible to know whether he is a presuppositionalist or not. If he uses the Van Fraassen form, then he is a presuppositionalist. If he uses only the traditional arguments, then he may or may not be a presuppositionalist.
The concern of my earlier writings was that in seeking to “sharpen the antithesis” presuppositional apologists have sometimes been too harsh in evaluating the apologetic tradition and contemporary apologetic movements. When we recognize the continuities (along with the discontinuities Collett brings out) between traditional and presuppositional argumentation, we discover that presuppositionalists have more in common with the tradition than they have sometimes thought. And, given these continuities, presuppositionalists should be more open to learning from the tradition than they have sometimes been. No one should suppose that Collett’s paper negates or diminishes that sort of concern.
1 I doubt, of course, whether there is any such thing as an intelligible denial of the reliability of logic. I’m speaking theoretically and hypothetically here.
2 He does distinguish natural knowledge from faith by saying that the latter depends on revelation while the former does not. I think that distinction is wrong, and I think it has serious adverse consequences for Aquinas’s system. This distinction exposes Aquinas as an advocate of “neutral” reasoning in the sphere of natural reason. But this error is not relevant to the question discussed above, namely whether Aquinas thought the existence of God to be necessary for intelligible predication.
3 The argument itself entails the transcendental conclusion. But apologist A does not intend to use it for that purpose, and he may even be ignorant of that entailment. Apologist B does intend to use it for that purpose, i.e. transcendentally.
4 I’m emboldened to say this by recent email correspondence with him.