David Reiter’s Interesting Modal TAG
David Reiter (Associate Professor of Philosophy at Erskine College) offers Don Collect’s Causality Transcendental Argument1 (see Reiter’s article for the background exposition and the previous argument forms) constructed from Strawson’s notion of Presupposition:
Transcendental Argument (2)
- C [i.e., There is causality] presupposes G [i.e., God’s existence]
So 3. G.
And TA (3):
- C presupposes G.
- ~C [i.e., There is no causality]
So 3. G.
David Reiter observes: “The central and critical point here is that we can validly derive God’s existence as long as the causality premise (there is causality) merely has truth value… This is what makes the transcendental argument (TA) such a daring move in Christian apologetics.”
Reiter argues that the above TA “only establishes the actual existence of God, it does not establish the necessity of God’s existence,” since it lacks a modal conclusion.
All the work in complete italics is mine and not Reiter’s.
I would like to explore his employment of the term actual; I maintain that when discussing God as actually existing, it seems to point toward God necessarily existing.
• God is an actual given in a possible world W if, and only if, He has complete omnipresence in W; and
• God is omnipresent if He has complete presence in every possible world.
• Omnipresence is possibly exemplified. That is, it is possible that there is a God who has omnipresence.
• Therefore, possibly it is necessarily true that an omnipresent God exists.
• Thus, it is necessarily true that an omnipresent God exists.
• Therefore, an omnipresent God exists.
When one perceives how the argument works, you might think that asserting or affirming the premise is tantamount to asserting or affirming the conclusion; the astute atheist may assert that he does not believe it is possible that there is a God. But could not a parallel criticism hold of every valid argument? Take any valid argument: after you perceive how it works, you may think that asserting or affirming the premise is tantamount to asserting or affirming the conclusion.
If there are things that transcend the material realm, including God, necessarily; a necessary entity cannot be grounded by a contingent world or series of worlds. In contrast, non-theism rests upon a contingent world or worlds. Consequently non-theism lacks the necessary endowment to underwrite necessary truths.
A second possible argument that attempts to move from God’s actuality to necessity:
• God is actual in a given possible world W if, and only if, He is necessary in W; and
• God is actual if He is necessary in every possible world.
• Actuality is possibly exemplified. That is, it is possible that there is a God who is necessary.
• Therefore, possibly it is necessarily true that God exists.
• Thus, it is necessarily true that God exists.
• Therefore, God exists.
Logically it’s more than problematic to demonstrate that a necessary being’s existence is impossible; there appears to be modal reasons to affirm that a necessary being, God, by definition, exists.
Reiter notes: “Van Til holds that predication is impossible apart from God’s existence. This predication claim amounts to the conjunction of”:
(a) There is no possible world where some proposition p is true and God does not exist.
(b) There is no possible world where some proposition p is false and God does not exist.
“More compactly, the presuppositionalist claim is as follows:”
- There is no possible world where some proposition p has a truth-value and God does not exist.
- There is some proposition p that has a truth-value in the actual world (e.g. the proposition Lincoln is the state capitol of Nebraska has the truth-value of true).
- So God exists in the actual world.
He then offers this analysis: “This is a maximally versatile argument form in the sense that the existence of God follows validly form the truth or falsity of any proposition whatsoever.”
He adds: “But it only yields the actual existence of God—it does not yield the modal claim that God exists in every possible world (i.e., that Necessarily God exists).”
Incorporating this supposition then yields the following argument form:
- There is no possible world where some proposition p has a truth-value and God does not exist. [Presuppositional Claim.]
- For any possible world W, there is some proposition p that has a truth-value in W.
- So, For any possible world W, God exists in W.
Reiter apprises: “I call this argument form the form The Transcendental Argument from Presupposition. This argument is perfectly valid, and it yields the modal conclusion that God exists in every possible world.”
Reiter then outlines Sean Choi’s reconstruction of Bahnsen’s TAG and agrees with Choi as he deems it insufficient at proving the conclusion of Christian theism since some other species of theism may be maintained in the same manner.
Reiter asserts that “if the goal is to construct an argument for the necessary truth of Christian theism … then the transcendental premise is appropriate and necessary. … let us at this point introduce the general form for a Modal Transcendental Argument, as I shall call it:”
(MTA1) It is necessary that q.
(MTA2) It is necessary that if not-p, then not-q.
So, (MTA3) It is necessary that p.
Reiter at that juncture comments: “The important revision here (relative to Choi’s analysis) is that both the granted premise and the transcendental premises are necessary propositions. … We can now express the Modal Transcendental Argument Form as follows:
MTAG1. It is necessary that there is a proposition that has a truth-value.
MTAG2. It is necessary that if God does not exist, then it is false that there is a proposition that has truth-value.
So, MTAG3. It is necessary that God exists.
Reiter completes his proposal: “The overall conclusion of our discussion is that a TA intended to establish the necessity of God’s existence must be purely transcendental—i.e., it must be composed exclusively of necessary truths.”
It is essential that the reader studies the complete article to adequately understand the scope and refinement of the author’s exposition.
Notwithstanding the philosophical specialization, Reiter’s article is worth reading. It will alert apologists to the philosophical strength of Transcendental Arguments for the Existence of God and the recent objections to them. It will also interest scholars of religion and philosophers working with modal logic. For contemporary presuppositionalists Reiter does not disappoint as he employs high levels of precision, rigor, and innovation that will benefit many readers. The author offers a quick pace sweep from Van Til, Bahnsen, Collect, and Choi. The article develops an innovative view concerning the epistemology and metaphysics of the modality of TAs—truths concerning what is actual, possible or necessary. This framework is then applied to a re-examination of the Transcendental Argument for God.
Acquire the journal The Confessional Presbyterian to see the full article inasmuch as it is carefully argued re-evaluation of the relation of necessary existence and transcendental argumentation, casting welcome new light on contemporary discussions. This is a must-read for all thoughtful apologists and theistic philosophers. Bravo David Reiter and Chris Coldwell!
Purchase this issue or subscribe to The Confessional Presbyterian at: http://www.cpjournal.com/2011/05/the-confessional-presbyterian-7-for-2011/
1. David Reiter: The Confessional Presbyterian, 7 for 2011