This is number 4 in the new series on presuppositionalism. Both the old series and the new are collected under the rubric Van Til and Presuppositionalism. The old series consists of five entries written between January 17th and February 9th, 2019. 

Today's entry examines a passage from Cornelius Van Til's The Defense of the Faith, 4th ed., P & R Publishing, 2008, p. 294. I have intercalated numerals in brackets so that I can refer to the sentences seriatim for purposes of commentary and critique.

The main question I want to raise is whether Van Til and such of his followers as Greg L. Bahnsen conflate epistemic modality with real (ontic) modality.  See the Internet Encyclopedia of Philosophy for an introduction to the distinction. Here is the Van Til passage for analysis:

[1] One’s conception of reality is one’s conception of the foundation of the laws of logic. [2] If men are 'neutral' in their methodology, they say in effect, that as far as the possibilities involved in their investigations are concerned, God may or may not exist. [3] The facts and the laws of this universe may or may not  be sustained by God. [4] The law of contradiction does not necessarily have its foundation in God. [5] A may be A tomorrow or it may be not A tomorrow.

Ad [1] So far, so good.

Ad [2] It seems to me that Van Til is here confusing epistemic with real (ontic) possibility.  We are told that for the neutralist, God may or may not exist. But "God may  or may not exist" is susceptible of two very different readings, one epistemic, the other real, the first arguably true, the second arguably false.

Read in terms of epistemic possibility, the sentence says that both the existence of God and the nonexistence of God are consistent with what we know. It says that neither state of affairs is ruled out by what we know.  For all we know, God might exist, but then again, he might not. By 'know,' I mean what we humans actually know 'here below,' in our present state, i.e., this side of the grave.

As I have made clear in earlier entries, my position is that both the existence of God and the nonexistence of God are epistemic possibilities. Both are possible for all we (can legitimately claim to) know. It follows that both theism and atheism are rationally acceptable. To whom? To us, not to God obviously.  (If God exists, you can be sure that he is a theist!) There are rationally acceptable arguments on both sides of the God question, but on neither side are there rationally compelling arguments. It is reasonable to be a theist, but it is also reasonable to be an atheist. This is my 'signature thesis.' The thesis could also be put as follows: the existence of God is epistemically contingent, which implies that it is not epistemically necessary, and therefore not objectively certain, however subjectively certain it may appear to Van Til or anyone else. 

My 'signature thesis'  will be strenuously resisted both by dogmatic theists and by dogmatic atheists.  These dogmatists think that they can prove, i.e., establish with objective certainty, that either God exists or that God does not exist. I take an anti-dogmatic line, a critical line. 

My anti-dogmatism, however, does not make me a skeptic about the existence of God.   I neither doubt nor deny the existence of God. I doubt that the existence of God can be proven, just as I doubt that the nonexistence of God can be proven.  It must remain an open question on the theoretical plane in this life.  My stance is critical and thus neither dogmatic nor skeptical. It could be called zetetic to avoid the unfortunate connotations of 'skeptical.' My critical stance, while zetetic, is consistent with taking a position on the God question: it is consistent with affirming the existence of God.  It is just that this affirmation is pistic (by faith) rather than epistemic (by knowledge). I am not a Pyrrhonian skeptic who suspends belief, retreats to the quotidian, forgets about God and the Last Things, and lives the life of the practical atheist. I live the life, or try to live the life, of the practical theist: I live on the assumption that God exists, but without the conceit that I can prove that God exists, thereby resolving the issue on the theoretical plane.  But a question that cannot be resolved impersonally on the theoretical plane can be decided personally on the practical plane.

Read in terms of real (non-epistemic or ontic) possibility, "God may or may not exist" says that God is a contingent being. It is however false that God is a contingent being as I am sure Van Til would agree: nothing could count as God that either merely happens to exist in the manner of a brute fact, or is caused to exist by another.  

One who fails to make the distinction between epistemic and real possibility might think that the falsity of the second reading entails the falsity of the first. But that would be a mistake.  I suspect that it is precisely this mistake that Van Til is making. He incorrectly thinks that because the existence of God is not ontically contingent, but is ontically necessary, the existence of God is epistemically necessary, i.e., ruled in by what we know and thus objectively certain.  

But surely the existence of God is not ruled in, or entailed, by anything we can legitimately claim to know. If Van Til or his acolytes were to respond: "But we do know that God exists because his existence is attested by the Word of God, the Bible," then he or they would be arguing in a circle. But as I took pains to show in earlier posts, no circular argument is probative.  A tenable presuppositionalism must somehow avoid circular reasoning. "Presuppers" are, I take it, aware of this requirement which is presumably why they  present their position in transcendental form.

A transcendental argument is one that starts from some actual fact and then regresses to the necessary condition or conditions of the possibility of our knowledge of that fact. Such an argument does not move in a circle.  To keep with the geometrical metaphor, a transcendental argument moves linearly and 'vertically' if you will from the plane of the actual to a dimension orthogonal to that plane, the 'transcendental dimension' wherein are to be found the necessary epistemic conditions of the possibility of our knowledge of the the items on the plane of the actual.  The problem, of course, is to prove and not merely presuppose that God inhabits that dimension. The problem is to show that God and only God could be the ultimate transcendental condition of possibility.  And please bear in mind that the God in question is the God of the Christian Bible interpreted along Calvinistic lines. 

Ad [3] Van Til thinks that if God may or may not exist, then "The facts and the laws of this universe may or may not  be sustained by God." Here again is the same epistemic-ontic confusion. What Van Til says is true only if God is ontically contingent. For if God is ontically contingent, then it will be possible for the facts and laws to exist and be what they are if not sustained by God. But if God is ontically necessary, as both Van Til and I believe, then, given that God is the creator and sustainer of everything distinct from himself,  it will not be possible that there be uncreated and unsustained facts and laws.

Epistemically, however, it is possible both that the  facts and laws are sustained by God and also that the facts and the laws need no divine sustenance.   For example, David Armstrong's naturalistic but non-regularity theory of laws as relations between immanent universals is epistemically possible but has no need for God as sustainer of laws.  (See D. M. Armstrong, What is a Law of Nature? Cambridge UP, 1983) Of course, if God exists, then he is the sustainer of natural laws. But whether God exists is precisely the question. (It is an elementary point of logic that when one affirms a conditional proposition such as the one two sentences up, one is not affirming the antecedent of the conditional.) 

In sum, Van Til is on solid ground  in holding that God is an ontically necessary being.  But this gives him no good reason to think that God is epistemically necessary.  By my lights, Van Til is conflating ontic and epistemic modality.

Ad [4].  Here we are being told that on a neutral approach, "The law of contradiction [LC] does not necessarily have its foundation in God." But here again we find the epistemic-ontic confusion. On a neutral approach, it is epistemically possible that LC, a necessary truth, be grounded in God, a necessary being,  such that if God were not to exist, LC would not exist or be true.  But it is also epistemically possible that LC, a necessary truth, subsist as a proposition and be true even if there is no God. Neither epistemic possibility can be ruled out by what we can legitimately claim to know. It is therefore epistemically contingent whether LC has a divine ground. This is why it is a question whether LC requires a divine ground, an open question not to be begged.  If a Van Tilian replies that we do know that God exists because the Bible says so, then he moves in a circle of embarrassingly short diameter. Obviously, one cannot prove a proposition by presupposing it.  If, on the other hand, one argues along the lines of the Anderson-Welty argument from the laws of logic to the existence of God, one will at most succeed in showing that the existence of God is rationally acceptable, but will not succeed in proving  the existence of God, and this for the reason that one or more of the premises may be reasonably doubted as I point out in the linked article.  It is because one cannot compellingly or coercively demonstrate the existence of God by either a circular argument or a non-transcendental argument such as the Anderson-Welty argument that the presuppositionalist tries for a transcendental argument.  My point, however, is that such an argument may conduct us to a transcendental condition of intelligible predication, but cannot demonstrate that God and God alone is (identically) that  transcendental condition. 

Ad [5]. We are here being told that on the neutrality approach, "A may be A tomorrow or it may be not A tomorrow." I take it that 'A' names a proposition.  The claim seems to be that the very identity of a proposition cannot be secured unless the laws of logic have a divine foundation. But why? Let 'A' name the Law of Contradiction (as Van Til calls it.)  The law in question is necessarily true and necessarily existent.  This is the case whether or not God exists. If it could be proven that LC could only exist as a divine thought-content, then it would be proven that the laws of logic must have a divine foundation.

But how prove that? I have shown that circular arguments and transcendental arguments and non-transcendental arguments such as the Anderson-Welty argument are all unavailing.