Dr William Lane Craig offers a brief response to the challenge often posited by atheist Christopher Hitchens, and others: “Name a moral action that a religious person can do, that a non-religious person cannot.”

Mitchell LeBlanc, owner of UrbanPhilosophy.net and Philosophy of Religion student at University of Toronto, has recently proposed “A Possible Disproof of God’s Existence,” which is basically a slight reformulation of an argument presented by Michael Martin about twenty years ago, [1] wherein LeBlanc simply replaces all instances of “omniscient” with “triune” instead. In this argument he attempts to prove that God does not exist—indeed cannot exist—by reason of a logical contradiction. Whether or not his argument achieves its aim shall be the subject of this brief article.

Although I will not be analyzing Martin’s argument directly here, I will be doing so indirectly since LeBlanc’s argument is essentially identical to it; therefore, any criticism that applies to one will apply to the other. The argument LeBlanc constructs is as follows:

(1) If God exists, then God is necessarily omnipotent and necessarily triune.

(2) If God is necessarily omnipotent, then God necessarily can bring about any logically possible state of affairs.

(3) If God necessarily can bring about any logically possible state of affairs, then God necessarily can bring about a state of affairs that is brought about by a being that is not necessarily triune.

(4) If God necessarily can bring about a state of affairs that is brought about by a being that is not necessarily triune, then God is not necessarily triune.

(5) Therefore, God does not and cannot exist

What LeBlanc is attempting to argue for here is that God possesses attributes which logically contradict each other. To fashion an argument which proves that God cannot exist is something of a Holy Grail to many atheists, and continues to be every bit as elusive as that mysterious chalice. In this argument LeBlanc reaches out to grasp it but finds only air, for his argument commits a substantial error in reasoning.

Given the first two premises (which must be given, as we are confronting orthodox Christian theism), his third premise ought never obtain; i.e., in order to obtain (3) LeBlanc is forced to contradict (1) and (2)!

How so? Consider what it is that (3) asserts: that God necessarily can bring about some X such that it was brought about by a being that is not necessarily triune. But given (2) which defines omnipotence as being able to “bring about any logically possible state of affairs,” and given (1) which defines God as “necessarily triune” (it is not logically possible for God to not be triune), we therefore observe that (3) contradicts these very premises—so that it is not God who vanishes in a puff of contradiction but rather LeBlanc’s argument.

[1] Martin, Michael. Atheism: A philosophical justification (1990), pg. 310, as cited by LeBlanc.

LAST UPDATED: 7 September 2009

PREFACE: The following article was originally published in three different places, two which died internet deaths and one that still exists as an inactive blog. [1] Shortly after publication it caught the attention of Austin Reed Cline, a Regional Director for the Council for Secular Humanism and editor of the Atheism section of the About.com site, who published an excoriating and profoundly inaccurate review thereof. [2]

I invited Cline to interact with me on the subject because I intended to compose a rebuttal and wanted his input before publication; I also asked if he would be willing to provide a link to my rebuttal. On both counts he refused, and with some rather insulting remarks. So I had to complete my rebuttal without any input from Cline. Unfortunately that rebuttal was published at one of those now-dead locations, a web site that died when my hosting company went out of business.

I am republishing the original article here along with a new rebuttal against Cline (which I will finish by this weekend) for the thoughtful consideration of our readers and members. Please feel free to weigh in with your thoughts on my original point, on Cline’s review, and on my rebuttal.

Original Article (27/Jan/2005):

The really frustrating thing about most atheists, at least those who enjoy debating against Christian theism, is that they presuppose the truth of their system of belief and then tacitly insist their Christian opponent work within the framework of that system. In other words, the Christian is expected to provide arguments in defense of Christian theism which accord with the atheist’s epistemology in particular and world view in general. This is implicitly demonstrated in challenges such as, "Provide evidence that God exists." The relevance of evidence, and even what constitutes evidence, are defined by his system of thought.

However, if it is permissible for the atheist to presuppose the truth of his system of thought and expect the Christian to work within the framework of that system, then it is also permissible for the inverse of that situation. Otherwise, the atheist would shoulder the epistemic responsibility for explaining why the only presuppositions permitted in the field of debate are his own—and I would not anticipate a rational argument for that.

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