Yes, Jackie. 3b covers part 1a of my challenge. 1b is to give me another instance of its being used with that meaning. I liked Dr Bill's Quinion link in terms of its comment on the translation of petitio principii.

And, dody, beg the question is the standard form. The phrase is often used to mean "raise the question" or "leave the question unasked." This is the usage shanks was objecting to.