William Lane Craig has a standard set of responses to the line of thought I've laid out over the last couple of posts. His first has already been alluded to. He argues that his claims rest on metaphysical assumptions and can't be challenged empirically. This is just false. I've already explained why he makes empirically testable predictions. Now, let's look at the rest of his arguments:
On virtual particles:
But there is much debate over the actual existence of virtual particles. Also, virtual particles pop into existence 'uncaused' only given indeterministic interpretations of quantum mechanics like the Copenhagen interpretation, but that may be the wrong interpretation, and most interpretations of quantum mechanics are deterministic, and would not suppose that virtual particles come into existence uncaused. Thirdly and most importantly, even on indeterministic interpretations, virtual particles do not come into being out of nothing. They arise from fluctuations of energy contained in the subatomic vacuum. [Craig & Sinclair, 2009]
First, virtual particles exist. They've been empirically demonstrated.
Second, my entire last post dealt with interpretations of quantum mechanics. I've already explained why Craig has no justification for denying Copenhagen or picking one other interpretation over another. For Craig to get what he wants here, he either needs for there to be time travel or many worlds. He conveniently fails to mention that in his above paragraph, because he has no reason to believe the first is the case and he would abhor the implications of the second.
Third, Craig argues that quantum fluctuations don't undermine his argument because they don't come from nothing. This is just willfully missing the point of the argument. I don't care if they come from nothing. If they are uncaused, whether it came from nothing or not is a moot point. You can go down the rabbit hole of discussing whether or not the multi-verse creates problems for atheists, but better people than I have explained why Craig's arguments fail in this regard. What matters here is that Craig's first premise is false because that premise holds implied premises we can't justify. If Craig isn't going to defend his notion of causality, then he has no justification for all of the arguments he makes based on that notion.
Every single time this is brought to his attention, he makes hand-waving arguments about metaphysical truths. That's code word for unjustifiable presuppositions. You can get away with that with regards to subjects like objective reality and consistent laws of the universe, because we don't have good empirical reasons for calling those into question and all of the evidence to date supports them. We have damn fine empirical reasons for calling our notion of causality into question, and all of the talk about metaphysics and vague references to possible future discoveries in physics isn't going to change the fact that our best current understanding of the universe shows Craig's presupposition to be very questionable.