This will be just a brief note on part of the Stephen Law’s presentation on the strengths and weaknesses of The God Delusion, which, since it is related to remarks made by Peter Williams considered earlier, is worth while inserting here. First the six and a half-minute clip where he discusses Alvin Plantinga’s response to the central argument of The God Delusion.
I disagree with Law’s assessment of Plantinga as a very very good philosopher. But, having said that, notice that this is a bit like Williams’ argument about artifacts and artisans and then following up with necessary or impossible gods. How convincing is it? Stephen Law calls this the heavyweight argument, having already disposed of Swinburne and Craig. But how compelling is it? It may be true that explanations come to an end, but what Law does not seem to see is that if the argument is valid, it is an explanation for life on earth. In other words, Plantinga is presenting us with Intelligent Design theory. Does Law want to follow him along this particular train of argument?
For we already know, independently, that life on earth gives the appearance of design, and that there is no reason to think that it is actually designed by a designer. It is reasonable, based on what we know, to infer, from the existence of tractor-like machines on an alien planet, the existence of intelligent beings who designed and manufactured them. That is merely an inference based on experience. But, even if we are only trying to explain the complexity of life on earth — and Law is unclear as to what we are trying to explain here – there is no reason, based on our experience, to make the inference to the existence of a non-physical, purely spiritual, or mental, supernatural, designer.
Now, we have to remember what the God Hypothesis (the GH of that last screen) is. Here is Dawkins’ formulation:
… there exists a super-human, supernatural intelligence who deliberately designed and created the universe and everything in it, including us. 
So the God Hypothesis, for Dawkins, is, in fact, an ultimate explanation of organised complexity, not just for the existence of terrestrial life. It is not like coming upon something which appears to be designed and manufactured in ways familiar to us. Recall that in his Natural Theology, William Paley encouraged us to look at living things and manufactured things as being similar in precisely the way that Plantinga is suggesting. And so long as he keeps the description vague, he can almost get away with it, for, as we know, until Darwin, as the example of Hume makes clear, it was not easy to see the distinction, although it was obvious that Hume felt that there was a significant distinction to be made. Darwin’s theory made it clear what the distinction was, and why it was so important to make it.
Seeing that there is a distinction to be made between designed things (like watches), and things which appear to be designed (like animals and plants), but are instead the outcome of mindless physical processes, is vital to Dawkins’ argument. If the inference in the first case, say, to Williams’ artifacts from the second century BC[E], or Plantinga’s tractor-like objects, is reasonable, that is, if it is reasonable to infer an intelligent designer, it does not follow that it is reasonable in the second, for we now know that living things are not designed, but are the result of random variation and environmental selection. And talking about the necessity or the impossibility of gods, or about the fact that explanations must come to an end, does nothing to change this. That is just so much hand waving, once we see the trick that Plantinga is trying to play on us.
I conclude, therefore, that Law has not shown that there is a serious flaw in Dawkins’ central argument. It may be flawed in other respects, of course, but not in this one.