 First, if a (conjunctive) proposition’s seeming, after careful and repeated scrutiny, to be or entail an explicit logical contradiction is not sufficient, or at least good enough, evidence of its being a contradiction, what would be? To put it another way, one’s inability to explain how it could be true both that p and that q does seem to be pretty good (non-demonstrative) evidence that p and q are not both true. Now it was noted above that the actual is possible whether or not one can explain how it is possible.  Granted, but if one cannot explain the ‘how,’ doubt is cast on the actuality. The tables can be turned. How adjudicate between these opposing lines of argument: A: Because X is actual, X is possible, whether or not anyone can explain how it is possible! B: Because no one can explain how it is possible, it is not possible, and therefore not actual!