Apologetics to the Glory of God

A Brief Word On The Transcendental Argument For The Existence Of God

Immanuel Kant is known for having coined a term and utilized an argument which is now referred to as transcendental, though it may be traced back even further, having been used in some sense by Aristotle (as one example). Cornelius Van Til, writing from the Continental Tradition in Philosophy, wrote extensively concerning a transcendental argument which is utilized to prove Christianity. Greg L. Bahnsen, a student of Van Til, is best known for having brought the argument, or at least something very much like the argument, into the realm of public debate and for having attempted to clarify it a bit further. Philosophers in the Analytic Tradition in Philosophy have also picked up upon the use of transcendental arguments, though many years after Van Til. Some philosophers and apologists who are generally sympathetic to Van Til and Bahnsen’s overall program but are nevertheless critical of even the more fundamental aspects of the method and argument have developed their own take on presuppositional apologetics and what is now traditionally referred to as the Transcendental Argument for the Existence of God or “TAG”. From this group have come both the “Modal TAG” and its alleged refutation, or at any rate the claim that it does not prove what it claims to prove.

My opinion on the matter will remain hidden for now other than to state those in the latter group I mentioned have done much more, in some respects, than the more purely Van Tillian apologists have in explaining, clarifying, and even using the style of argumentation they might still dub “presuppositional” or even “transcendental”. In actual practice there is sometimes no way to actually tell which of the (at least two) styles of argumentation is being employed. Given the contexts I have used apologetics in during the last several years; I have had little worry about whether or not I used pure Van Tillian rhetoric or even argumentation in the narrow sense. There is, however, a huge difference between the positions that is noteworthy especially when offering a critique of one of them.

In his article on The Transcendental Argument for the Existence of God Mitch Leblanc relied heavily upon a strong Modal TAG and arguments that have been brought against it.1 In subsequent discussion about the article he claimed, repeatedly, that this was only a formal representation of what Bahnsen offered in his debate with Gordon Stein. Mitch has a great deal of people on his side in claiming that the deductive formulation of TAG he offered in his article is the only valid formulation of TAG, but of course this does not mean that he is right. This post is not about sparking another debate with Mitch on the topic, but for the sake of clarity I would like to offer this bit of information.

The transcendental argument as Van Til and Bahnsen put it starts with the question, “What are the preconditions for the intelligibility of reality?” The argument was considered by these men to be both indirect and unique. Indirect means that the apologist using the argument would not be using either “evidence” or “arguments” directly as they are used in the traditional and evidential theistic proofs such as those presented by Thomas Aquinas. The “facts” and “laws” are both of God, and hence even an argument like the deductive Modal TAG already presupposes the existence of God. This allegedly takes into account the character of God in a way that the traditional arguments do not in that God is necessary, absolute, and incomprehensible, etc. God is thus to be argued for in such a way that his logical primacy is taken for granted rather than rejected with the result, through inductive or deductive arguments, that God is logically derivative. Neither inductive nor deductive arguments as a whole provide certainty and instead are probabilistic such that it may only be said that God “probably exists”; but if God probably exists, then He probably does not exist as well, howbeit the probability that he does not exist may be considered smaller than the probability that he does contingent upon the “evidence”. This leads into why the argument was taken to be not only indirect, but unique as well; it is supposedly neither inductive nor deductive, but rather transcendental. The transcendental argument involves the claim that the very notions of possibility, probability, deduction and induction presuppose the Christian worldview; so that it is impossible to ever intelligibly do anything other than presuppose that Christianity is true, regardless of whether or not one argues for or against Christianity.

It is problematic then, to formulate an argument in an inductive or deductive manner and then attribute this argument to the likes of Van Til or Bahnsen, who were both philosophically able men. It may be the case in the end that transcendental arguments are, as I think Mitch would say, “invalid”, but with the claim there would need to be an argument, and once the argument was established one might reasonably say that Van Til and Bahnsen failed. One may ask what is meant by “invalid” here though, for this often involves the assumption of deductive standards of argumentation, and both Van Til and Bahnsen rejected the claim that their method was either inductive or deductive. (This may be analogous to the complaint made in literature on inductive reasoning that philosophers have been much too hasty, and are incorrect, in criticizing induction based upon the standards utilized for deduction, since the two methods of reasoning are both clearly methods of reasoning and yet are distinct from one another.) This is likewise problematic when it comes to the formulation of TAG as Van Til and Bahnsen would have it, for when the formalization is requested it is usually expected to be produced in accordance with deduction. If it turns out that the argument cannot be stated except as an inductive or deductive argument, can it really even be called an argument? To answer in the affirmative would be to beg the question against transcendental arguments, but then, there does appear to be a need for some kind of clear statement of the argument.

One way in which to state the TAG is as follows:

C presupposes G        (premise 1)

C                                       (premise 2)

Therefore G                 (conclusion)

Stating the argument in this way would result in both an indirect and unique application of argumentation to the apologetic endeavor.2 During our discussion, Mitch denied this, stating “the form of TAG is not unique/indirect, it’s simply modus tollens”.

Modus Tollens is a valid form in classical logic which looks like this:

If P, then Q


Therefore, ~P


It is difficult to see how this might be used as descriptive of the TAG as offered above, for the two are not the same. Deductive arguments are in fact, not transcendental arguments, and we may illustrate this as follows:



Logic presupposes Christianity


Not Logic


Therefore, Christianity


Modus Tollens


If Logic, then Christianity


Not Christianity


Therefore, Not Logic


In the first argument, the denial of logic implies Christianity, while in the second argument, the rejection of Christianity results in the rejection of logic. The arguments are not the same. We may even switch the second argument around and still have very different results than what the TA yields.

Modus Tollens


If Christianity, then Logic


Not Logic


Therefore, Not Christianity


Arguing against, for example, the strong Modal TAG as though it is the same thing as TAG the way it was understood by those who are known best for developing it can have devastating effects upon the critique, and this is just one example. It is important to briefly describe one more example.

The TAG is not set forth as utilizing some sort of inductively proven deductive premise like Mitch presented in his article. To clarify, the “impossibility of the contrary” utilized in transcendental arguments is not taken to mean the impossibility of infinite or even indefinite possible worldviews which are allegedly shown to be impossible inductively (though I have seen no argument as of yet that this is impossible to accomplish), but rather that the autonomous and univocal negation of Christianity is false which is shown through a reductio ad absurdum applied to the worldview.

What has been offered is not to be taken as a clear statement concerning my own view on the matter nor a defense of either my view or of the “TAG” formulas, but it is clear that in cases like the article written by Mitch (and there are many, many other examples), we should at least be clear about what we are doing. As I already mentioned, it may be the case that Van Til and Bahnsen have a shoddy argument (so far as the subject of this post is concerned), but if this is the case it is much easier and I dare say much more honest to just say so and show it rather than offering something in the argument’s place and calling it the same thing!






1To be fair, Mitch opens with:

(1) P

(2) If not-Q then not-P

(3) Therefore, Q

Where P is Logic and Q is the Christian God

This may be restated:

(1) If Not-Christian God then Not-Logic

(2) Logic

(3) Therefore, Christian God

The reason the premises might be presented in a different order is so that one might “start with logic” in one’s argumentation. Mitch writes that this argument is an instance of Modus Tollens and I think that he is right to do so.


2Another way of stating it would be to replace “C” in premise 2 with “~C”. This is done in the illustration which follows the initial statement of the argument.


8 responses to “A Brief Word On The Transcendental Argument For The Existence Of God”

  1. ZaoThanatoo Avatar

    I think under your second TAG section, you mean for the second premise to be “Logic” (not “Not Logic”), that is, if it’s going to be consistent with the first example (“C presupposes G…”).

  2. C.L. Bolt Avatar

    The premise “Not Logic” is intentional and not necessarily consistent with the first example.

  3. ZaoThanatoo Avatar

    Okey dokey.

  4. Mitchell LeBlanc Avatar

    What about the form I’ve offered in my paper?

    (1) P

    (2) If not-Q then not-P

    (3) Therefore, Q

    Where P is Logic and Q is the Christian God this seems to me to grasp the essence of what you intend to show.

  5. chrisbolt Avatar

    I stuck in a few footnotes, thanks for the comments.

  6. ZaoThanatoo Avatar

    Oh, I think I see…
    You’re using the non-traditional Don Collett-style (influenced by Strawson/VanFraasen) formulation of the TAG? (Have you been reading Oliphint? 😉 )

    But isn’t this really just an analog of modus ponens (resting on the definition of “presupposes” in the first premise) in this formulation?

    Nothing like mistaking a rather incisive argument for a type-o… Shame on me…

  7. […] wrote a “question” in response to this post regarding the self-evident nature of the basic laws of logic being “enough” to show that TAG is […]

  8. […] “No Place to Stand, Part II” (8/Dec/09), “Lost in a Sea of Subjectivism” (8/Dec/09), and “A Brief Word on the Transcendental Argument for the Existence of God” […]

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