When I come upon anything-in Logic or in any other hard subject-that entirely puzzles me, I find it a capital plan to talk it over, aloud, even when I am all alone. One can explain things so clearly to one's self! And then, you know, one is so patient with one's self: one never gets irritated at one's own stupidity!
They're talking about things of which they don't have the slightest understanding, anyway. It's only because of their stupidity that they're able to be so sure of themselves.