JB blogs quite effectively over at http://study-and-faith.blogspot.com/. Not of Mormon decent (or persuasion), JB is a seminarian with an interest in LDS-Evangelical dialogue.
One of the things JB does very well here is take me off whatever perch of self-assuredness I have regarding my own intellect. JB's brain is way above my pay grade, but I figure I'll muddle through and figure it out. Maybe you all can help me. What are your thoughts? Rebuttals? Questions? Support?
Here it is:
First, it seems to be a plausible initial premise that whatever has a beginning of its existence is caused to exist. This is actually a very weak sort of causal principle; others include statements like “whatever undergoes change, has a cause for its existence”, or “whatever exists but could have not existed, has a cause for its existence”. These, while perhaps true, are stronger than is necessary for the argument here. The weaker form can easily be defended by invoking virtually any form of the principle of sufficient reason, which itself has weak and strong variants (e.g., “Every true proposition has a reason why it is true”; “every true proposition that entails the existence of some concrete contingent object has a reason why it is true”; “there is a sufficient reason why some contingent concrete objects exist, rather than nothing at all”; “possibly, there is a sufficient reason why some contingent concrete objects exist, rather than nothing at all”).
I'm actually convinced that the strongest forms of the principle of sufficient reason are both true and defensible, based on the work of Alexander R. Pruss (see his The Principle of Sufficient Reason: A Reassessment; I need to get my hands on a copy of this again to re-review the argument); but, at the very least, it would seem vastly more plausible to accept some weaker form of the principle of sufficient reason (or of a causal principle) than not. Aside from its intuitive nature and its utility as a metaphysical first principle, the causal principle enjoys the utmost in inductive confirmation: we have extensive experience with things coming into being with a cause, and no certain experience of the contrary. Although quantum phenomena are at times suggested to be a counterexample, this is at most arguably true on some interpretations of quantum mechanics such as the Copenhagen interpretation, but is most definitely not the case (to my knowledge, at least) under, e.g., the Everett many-worlds interpretation or Bohmian interpretations of QM. Nothing in the empirical data requires us to deny causality even in the quantum realm. But even on indeterministic understandings of QM, indeterministic causation is causation nevertheless. Moreover, even on the most anti-causation construal, QM still retains a sort of 'material cause' in the energy-rich quantum vacuum itself. Hence, I don't think that quantum mechanics offers much in the way of counterevidence to what is otherwise a principle enjoying the best inductive support as well as the highest prior probability. In addition, some form of causal principle is foundational to scientific inquiry and, for that matter, practical life; were there no prohibition against utterly causeless events, why ought there be a cosmos rather than a chaos? These factors all suggest that, to draw a rather modest conclusion, the causal principle here employed enjoys considerably greater plausibility than its denial, and this is what is required for a successful philosophical argument. Furthermore, as a metaphysical rather than physical principle, this causal statement is universal in scope.
Second, it seems that our universe is a thing that had a beginning to its existence. Our universe can certainly, at least in the relevant respects needed here, be understood as a unitary thing; it exhibits distinctive properties all its own, and this is far more the case during its denser early life. Apart from the ample empirical evidence suggesting a beginning to the universe's existence, there are good reasons philosophically to regard time as finite in the past. For instance, suppose that the contrary is true: the number of physical events or set intervals that have become past is infinite. Then we might consider a thought experiment involving an immortal figure who, existing throughout the entire past, has always been writing an autobiography; stipulate also that he requires a year to record the events of a single day. When confronted with the question of the most recent day recorded, no day a finite time before the present is possible; the answer can only be a day infinitely prior to the present. This, however, is impossible, for the very same reason that counting down from infinity is impossible: infinity has no immediate precursor. The impossibility of the thought experiment cannot be attributed to any factor other than the supposition of an infinite past, which therefore cannot actually be the case. The past must be finite; that is, the temporal series of past physical events is not beginningless. But this just is to say that the universe had a beginning to its existence.
From the causal principle mentioned above (“whatever begins to exist has a cause to its existence”) and the premise that the universe had a beginning to its existence, it follows that the universe had a cause to its existence; the universe's existence is not a brute fact. Note that the argument is not circular, nor does it commit the fallacy of petitio principii, since neither of the two premises utilized so far rely on the assumption of the conclusion. One could be an atheist and accept the causal principle while (mistakenly, I think) denying that the universe had a beginning. Or, one could be an atheist and accept that the universe had a beginning while denying (very mistakenly, I think) the causal principle. Nor was theism invoked in the defenses of either premise above. So far as I can tell, the argument involves neither formal nor informal fallacies.
All that remains, then, is to investigate what could be inferred of the attributes of the cause of all space, time, matter and energy. (Even if the region we know as our cosmos were somehow spawned from a previous cosmos, as in certain controversial and highly speculative novel cosmologies, the above argument would apply just as well to any precursor cosmos; there can be no recourse to an infinite regress of cosmoi. Therefore, it is all space, time, and mass-energy that must here be accounted for.) The cause cannot, at least apart from the existence of the cosmos, be spatial, temporal, or material in character, as these are logically posterior to it. Whatever this cause is, then, it seems to be immaterial and eternal. It must also have the power to create a universe, which presumably is no simple task. Moreover, in contemporary philosophical discussion, there are only two known candidates for an immaterial and eternal entity: abstract objects, and minds. Abstract objects, by definition, are incapable of standing in causal relationships to anything; and therefore it stands to reason that, plausibly, the cause of the universe is an eternal mind (or minds, but the singular origin of the cosmos and Ockham's razor together suggest that the singular is more likely). This is further supported by noting that, of the two fundamental sorts of explanation ('scientific explanation' and 'personal explanation'), the lack of any possible (physical) laws to govern the origin of the first state of the universe indicates that the first sort of explanation is here inapplicable; the explanation must be of a personal sort, dealing in agents and volitions.
Hence, the conclusion I'd draw is that the more-plausible-than-not independent premises above lead to the conclusion that there is some cause of the first state of the space-time-matter universe; and that the most plausible characterization of such an ultimate, ultramundane cause is as an immaterial, eternal mind capable of generating the universe by an act of will. I would naturally hesitate to say that this argument proves that God exists, much less that this cause or God is adequately described by any particular religion or theological tradition. That would be overreaching the boundaries of this single argument. After all, nothing has been established about the cause possessing any other traditional divine attributes – nor, however, has the argument been intended to do that. However, it does seem to me that the conclusion drawn here renders theism of some sort more probable, in that no non-arbitrary non-theistic system tends to provide for such a mind causing the universe. A rather modest conclusion that I draw here is that the argument described above offers non-negligible rational support to theism.