As I contemplated Libet’s results, it struck me forcefully, this is exactly what the dualist-interactionist would expect. The soul (or mind) does not act independently of the brain; rather, as the Nobel Prize-winning neurologist Sir John Eccles put it, the mind uses the brain as an instrument to think. So, of course, the soul’s decisions are not simultaneous with the conscious awareness of them. How could they be? Given the soul’s reliance upon the brain as an instrument of thought and the finite velocity of the transmission of neural signals, of course there is a time lag between the mind’s decisions and the awareness of them
HHhhhwwwwhhat? Okay, let's say the soul acts on the brain like software on hardware. Why couldn't decisions be simultaneous with conscious awareness, since the soul is (presumably) responsible for conscious awareness as well? Why would there be any lag at all? Why would the "lag" be 550 milliseconds instead of 140 (or whatever)? Remember, in Libet's experiments the signal occurred before conscious awareness. Craig seems to be inadvertently suggesting that the soul is subconscious, since that is what he claims triggers the neural signals. I don't think ol' Bill thought about this one too hard.
Interestingly enough though, if this weren't the comical post hoc rationalization it obviously is, it actually would have made a valid falsifiable claim for the theory of substance dualism. Dualists could have predicted that the soul produces a "lag" on the brain within an estimated time frame, and bam, Libet's experiments would have provided real theoretical evidence for dualism instead of the usual philosophical bullshit.
Why didn't they do that? Well, because there's exactly zero independent evidence that "souls" actually exist (much less how they interact with matter), and everything we've learned about neurology overwhelmingly supports the materialist paradigm – that the mind is what the brain does. Neuroscientist Steve Novella expounds:
In science theories are judged not only by how well they fit the data, but by how useful they are as predictive models – and the materialist position that brain function is the mind has been fantastically successful.
There does not appear to be any intrinsic limit to our ability to map and alter anything considered to be part of our subjective experience. Damage or alteration to the brain can change your sexual identity, your moral decision making, your personality, your ability to even think about the world. Patients with non-dominant hemisphere strokes, for example, often have what is called neglect – they do not know that the left half of the world even exists. There is no model inside their brain for the left half of their body or the world, so they cannot even think about it.
Non-materialists often dismiss this as mere correlation, but that is not fair, in my opinion. The correlation is incredible, and predictive. To give just one more example, synaesthesia is the phenomenon of different sensory modalities mixing together, so synaesthetes will smell color or perhaps perceive numbers as having a physical texture. There is evidence for more robust neural connections and activity between the relevant brain areas in synaesthetes. That is a pretty compelling neural correlate.
Further still, the arrow of temporal correlation, which should go from cause to effect, seems to go from brain activity to subjective experience. Studies so far show brain firing happening prior to awareness of the subjective state.
This is the part where Bill Craig would say something like, "This doesn't show that a non-physical substance isn't acting on the brain!" and you deliver yourself a Class 4 facepalm.