If we do discover a complete theory, it should in time be understandable in broad principle by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason - for then we would truly know the mind of God.
The Mind of God is written to be a "scientific search for the meaning of the universe." Davies spends a fair amount of time talking about religion; as would be expected from the title; he is not particularly critical or uncritical of it, merely interested; religion is after all very important, historically at least, in the search for meaning in the universe. He would be described as pantheistic or deistic; so basically he is sympathetic to religious ideas so long as they are kept abstract and un-dogmatic.
I found Davies' writing strange; it seems paradoxically personal and impersonal. He lays out certain ideas, makes most of them seem plausible, and then, if he has one, tells you what his opinion is without ever justifying why that opinion is better than the alternatives. Hence it is a tentative book - which was what I expected.
Ultimately, there's one argument Davies is making: his final sentence is "We are truly meant to be here. I don't think he's argued very strongly for it; all he has done throughout the book is taken a look at certain aspects of science and carved a very rough path towards this conclusion. He provides no compulsion for why one should actually follow such a path - all he has said is that it seems to be there.
According to the blurb, he is "seeking to provide a glimpse at the meaning of it all." I don't believe he comes close to achieving this. The core argument is more that such a meaning exists at all, rather than that is is X or Y or whatever; the most that could be said is that he speculates a little on where one might look to "glimpse at the meaning of it all."
Look, it's an interesting read. There's some quality writing in here, and the ideas presented are interesting. I enjoyed it; but I would say that one definitely should not expect too much out of it. There's little real substance to it; it is a collection of interesting ideas lightly strung together (with the occasional bit of solid science) into a plausible but not overly convincing argument for an abstract philosophical idea. That is all, really. Three stars, perhaps.