I misunderstood you earlier, yes.

However, I think Guns, Germs, and Steel might be about as rigorous as that era of history can ever get. I've never encountered any historical arguments which cover such an unknown time period with such breadth and depth. If he were to increase the rigor of his arguments, we'd lose any chance at an overall picture.

Just because the books are accessible to the masses doesn't mean that the books aren't rigorous, which is what you almost seem to be implying with your above comment. Certainly, they're not perfectly scientific and can't be readily tested. But that can never happen in these fields, and the goal is only to move towards science as an ideal. You say that they weren't intended to be peer reviewed, but I guess I'm sort of confused as to why you believe that. There's nothing precluding experts from reviewing Diamond's findings, as far as I can see.

Regardless, there are some really really really bad social science arguments out there. If the average social science argument, or even some of the best social science arguments, reached a level of rigor and excellence comparable to Guns, Germs, and Steel then the field would be improved a hundred fold. Maybe this means that I've got pathetic standards for what constitutes rigor, but I prefer to think that I'm being realistic, as I think improving IR and economics to even this level of rigor is already a near impossible task.