Everyone is all in favor of scientific explanation, so with whom is he disagreeing? It seems that he wants to carve out a position that is opposite to mathematical Finitism and Logical positivism. He also dislikes the Copenhagen interpretation of quantum mechanics.
I defend logical positivism and Copenhagen. I should defend finitism also, as most math can be done from a finitary viewpoint.
Jared Diamond got famous for giving grand explanations for the history of civilization, but, as Deutsch points out, the evidence for those explanations is very weak.
Deutsch's book is interesting for his view of the world. However his specific arguments are not substantiated well enough to take seriously.