Curi,

"Some first chapter assumptions are incorrect or unargued. It begins with an example with a policeman, and says his conclusion is not a logical deduction because the evidence is logically consistent with his conclusion being false."

Popper's epistemology doesn't explain that the conclusion of the argument has no validty, in the sense of being certainly false. In fact, it requires that the conclusion is not certainly false. No conjecture is certainly false.

Perhaps you meant he shows that the argument is invalid in the sense of being a non sequitur. (A non sequitur can still have a plausible or true conclusion). Of course it is not valid in the sense of traditional, necessitarian deduction. The whole point is that it is something different. And the argument that this non-traditional, plausibility based deduction works is just the informal observation that we use it all the time and it seems to work. What else could it be? If were valid by taditional deduction it would BE traditional deduction.

" Later when he gets into more mathematical stuff which doesn't (directly) rest on appeals to intution, it does rest on the ideas he (supposedly) established early on with his appeals to intuition."

The Popperian argument against probablistic reasoning is that it can't be shown how it works. If Jaynes maths shows how it works, that objection is removed.

"This is pure fiction. Popper is a fallibilist and said (repeatedly) that theories cannot be proved false (or anything else)."

Of course he has to believe in some FAPP refutation. or he ends up saying nothing at all.