"Human beings, who are not gods, often fail to imagine all the facts they would need to distort to tell a truly plausible lie."

One of my pet hobbies is constructing metaphors for reality which are blatantly, factually wrong, but which share enough of the deep structure of reality to be internally consistent. Suppose that you have good evidence for facts A, B, and C. If you think about A, B, and C, you can deduce facts D, E, F, and so forth. But given how tangled reality is, it's effectively impossible to come up with a complete list of humanly-deducible facts in advance; there's always going to be some fact, Q, which you just didn't think of. Hence, if you map A, B, and C to A', B', and C', use A', B', and C' to deduce Q', and map Q' back to Q, how accurate Q is is a good check for how well you understand A, B, and C.