This is why I and many are skeptical about his claims. It may indeed be in the Q's nature to "seem" vulnerable, such as getting punched by Sisko, while being in complete control of every situation that could ever possibly exist. But how do we measure this? By what laws of logic does the Continuum operate? Simply saying that it's beyond our "puny" minds is a cop-out.
How so? That precludes the possibility that there are things that Humans simply aren't smart enough to understand, a rather arrogant belief. As for how we "measure" the Q, we can't. That's the whole point.