Beezle sums it up well:
Scientists generally suffer from overspecialization, but only because it’s now required due to the vast breadth of knowledge. They are generally NOT learned in philosophical issues, which is why when they are forced into a philosophical argument by a theist, they lamely fall back on sputtering something about falsifiablity, scientific method, and Popper, then promptly run out of gas.
This is true. And compounding the problem is that many scientists are so poorly learned when it comes to philosophical issues, (or most of the time, anything outside their specialty), that they don’t even realize when they are making a philosophical argument of their own volition; it’s seldom necessary for a theist or anyone else to force them into it.
It is a challenge to defeat a scientist in an argument related to his area of specialty. It is also a challenge to lose an argument to a scientist in just about any other area. For all that he comes off as an egregious buffoon most of the time, PZ Myers is strategically correct to stick to the petty name-calling that is the entirety of his method of argument relating to anything outside of his narrow field of science; attempting more would banish the illusion of his intellectual expertise and reveal the paucity of both his knowledge and his intelligence.