The Kalam Cosmological Argument is, essentially, the Argument from First Cause dressed up in new clothes. This isn’t really a bad thing. Of all the apologia that I encountered, my own personal opinion is that the two arguments which make the best case are the Argument from First Cause and the Argument from Design. Unfortunately, I believe that they also both partake of the same error, which Richard Dawkins has termed the Argument from Personal Incredulity. An Argument from Personal Incredulity is one where one attempts to make a case from a proposition on the basis of our inability to fathom or to explain a certain phenomenon or set of phenomena. In the case of the Argument from Design, the central proposition was that we have no means of explain complex "design" in biology, therefore we must assume the existence of a designer. The theory of evolution has since done a fair job of knocking out the pins from this argument, but, and this is an important point, even before we had a theory of evolution, the Argument from Design was still flawed. When one has a dearth of information on a subject, the best answer that one can give is to simply say, "I do not know the answer". Any attempt to fathom an answer from a lack of information is going to be epistemologically empty. It is my contention that the KCA suffers from precisely this sort of emptiness.
It rather mystifies me that Craig spends so much time offering a metaphysical argument for the fact that the universe has existed for a finite amount of time. The Big Bang model has been the accepted model for the formation and evolution of the universe for several decades now, and there isn’t anything approaching serious opposition to it anymore (there are numerous interesting refinements, but that’s another matter). It seems rather like using a deep and abstract philosophical argument to demonstrate that the earth must be round: a pointless exercise. Even so, given its prominence in the KCA, it behooves us to examine it. Alas, there is little to examine. When faced with the prospect of trying to imagine real infinities, Craig offers a number of thought experiments (i.e. Hilbert’s Hotel) in order to attempt to convince us that such infinities are impossible. Unfortunately he doesn’t offer us any logical inconsistency in the notion of real infinities, but rather simply declares that certain consequences of having real infinities are "absurd". Rarely does one see the Argument from Personal Incredulity so blatantly presented. I will grant that the guest shuffling of Hilbert’s Hotel is odd, and contra-intuitive, but that doesn’t invalidate its potential. Indeed, given that this weird shuffling is consistent with the very logic of transfinite sets, one would hope that anyone arguing from Craig’s position could offer us something stronger than a denial based on the intuition that things just can’t behave that way. It seems naive that Craig would expect infinite sets to conform to our expectations given that our expectations are derived from our experiences of living in a distinctly finite world. Science (especially 20th century science) has shown us that our intuitions are often grossly misleading. It doesn’t seem reasonable that something could simultaneously be a particle and a wave, and yet we have wave/particle duality. It doesn’t seem reasonable that time moves at different rates depending on your acceleration, and yet careful measures with atomic clocks have shown this to be true. It doesn’t seem reasonable that a single electron could interfere with itself, but all evidence to date indicates that this is exactly the case. In short, intuition is not a good guide. Sometimes nature behaves in ways that seem to us to be inherently absurd, but that is probably because our "ordinary" experiences represent a small slice of reality and that, outside of that slice, we must be willing to abandon our preconceptions even if the results do appear to be absurd.
Of course, I cannot help but to note that it is probably to the good that Craig’s arguments regarding "real" infinities (including temporal infinities) are so unconvincing, for if we were to accept them at face value, they would do away with the entire notion of an eternal creator. Craig’s arguments, after all, don’t simply posit that our universe is finite, but that it must, at a metaphysical level, be finite in duration, because real eternities can’t exist. It is perplexing, then, that Craig later introduces an eternal and uncreated Creator without so much as sparing a single sentence to explain this contradiction in reasoning. After all, if a man counting backwards from infinity and arbitrarily reaching zero as we meet him is "absurd", then what about a god counting backwards in like manner? If a hotel with an infinite number of rooms is impossible, then what of a god who is infinite in any dimension (even the dimension of time)? What sort of ontological distinction can we make that would allow room for the one but not the other? Craig doesn’t answer that, but I will hazard to guess that the likeliest answer would be one of special pleading: that God is an exception and that he doesn’t need to follow the rules (just as, somehow, we are expected to accept that all things need to be created... except God). To put it bluntly, if I allow Craig to convince me that the universe cannot be infinite in age, even in principal, then there is no room to put an eternal god. Craig cannot have his epistemological cake and eat it too.
Craig spends the second half of point 2 using cosmology to demonstrate the limited age of the universe. Here he is on solid ground. All evidence available does, indeed, indicate that the observable universe has only existed for several giga-years (the exact number, of which, is still in doubt). It is a non-controversial position, and he would have spared himself much effort (and dialectic inconsistency) if he had simply left it at that, rather than trying to form some ad hoc reason that the universe must be temporally finite. It is this tendency in the KCA that, I believe, Lusion refers to when he accuses Craig of indulging in "head speak".
Having established a relatively concrete fact (the universe has existed for a finite time), Craig attempts to extract a metaphysical truth (a god must have made the universe) from this. His arguments are interesting but, once again, have more sound and fury than substance. Craig’s central assumption is that whatever begins to exist must have a cause for its existence. Alas, Dr. Craig spends precious little time explaining why we must accept this axiom, stating that "it is based on the metaphysical intuition that something cannot come out of nothing". As I have already noted, intuition is not a firm foundation upon which to derive universal truths.
Strictly speaking, the issue of first causes deals with two separate issues: the issue of causation, and the issue of creation ex nihilo. The pure randomness and intrinsic uncertainty of quantum phenomena should be sufficient to banish the first claim. When one speaks of quantum uncertainty, one is not merely describing an observational limit to the universe, one is expressing a fundamental breakdown of our macroscopic expectations. Why does an electron appear in place X (more or less, given the uncertainty of position)? The only answer is that there was a certain probability that it would. There is no thing that caused it to be in X (more or less) than Y (more or less). It is the summation of these probabilities that lead to the statistical observation that A leads to B. At the quantum level, the best we can say is "If A, then maybe B, or possibly B’, or B’’, or B’’’..., to varying degrees of probability). So what about creation ex nihilo? Well, as John Gribbin notes in The Edge of Time the vacuum itself is subject to quantum uncertainty. If the energy of the vacuum were precisely zero, then there would be no uncertainty. The coscensus of Quantum physicists is that this manifests itself as a basic "frothiness" in the actual fabric of space-time. Since gravity counts as a negative in the equations, there is, literally, nothing in the laws of physics to prevent a vacuum from spontaneously "degenerating", nor any necessary upper bounds that such degradation can manifest. As one physicist put it, "Universes may be one of those things that happen, from time to time". I wish to emphasize that such degeneration is entirely consistent with our understanding of physics and that it provides some interesting possibilities when it comes to cosmogenesis.
Currently one of the hot topics in cosmology is the notion of inflation. Inflation is a model whereby a quantum fluctuation can be spontaneously blown up by quite a few orders of magnitude in a fractional amount of time. The details of it are too far to go into here [see The Inflationary Universe by Alan Guth], but it does provide one realistic model to account for Creation ex Nihilo, without the need to invoke a creator. I hasten to add that it is not the only model. Other models include such exotica as fractal scalar fields, baby universes born of black holes, Stephen Hawkings finite but unbounded view of time, and others. However, rather than get into detailed discussions regarding the pros and cons of these theories, I am simply listing them to note that there ARE theories out there which provide a potential framework for cosmogenesis that do not require anything like a "necessary being" (at one point in _A Brief History of Time, Hawkings wonders whether there is "any room for a Creator"). But rather than dwelling on these alternatives, let us return to the KCA and see what Craig provides by way of substantiating his claim that there is a creator.
In a word: nothing. When you boil the verbiage away from the KCA, you are left with precious little. Craig’s assertion that there must be a "necessary being" is firmly rooted in the notion that nothing else can account for the universe. As a pre-Darwinian atheist may have replied to the Argument from Design, I reply, "How do you know that this is the only alternative?"
This is especially pertinent given that Craig does not provide us with positive evidence for his Necessary Being. At most, he proclaims that the existence of the universe is a mystery that must be accounted for. However, when one is confronted by a mystery, and one cannot confidently demonstrate a solution to the mystery, the best possible answer that one can give is "I do not know."
Instead of this, Craig seems to be saying, "You don’t know, therefore I must be right -- it’s God."
It would seem that Craig has found a place to put God that is unassailable by science. The unassailability of that position is, even now, crumbling, and we have a number of alternatives with at least as much explanatory power as the deific hypothesis, but, even before the cracks started to appear in Craig’s Cosmological Conundrum, the argument was still faulty. Indeed, it was, as I said at the beginning, epistemologically empty. Given the framework of the KCA, until and unless Craig can provide us with a compelling positive reason to a) discard all of the competing cosmological hypothesis, and b) gives us a compelling reason to believe that no alternative hypothesis, conceived or otherwise, is viable, the KCA will be little more than a philosophical curiosity. As such, I don’t see much point to addressing the "beard" that Craig has put on his deity. The simple fact of the matter is that when one uses God as a placeholder for the unknown, one makes God into nothing more than a synonym for our personal ignorance.
 This is further muddled by it being in both
X and Y (aka in a "superposition of states") up to the point that
someone actual performs a measurement to determine its location.