What is "begs the question"

Usage examples of "begs the question".

Which begs the question, Why didn't I fuck off back to London with him?

But it still begs the question on certain aspects of vampiric lore.

Of course, that begs the question of who's the subordinate in this case.

If one begs the question of where all this world of material substance has come from, or how it is being continuously maintained in existence, then one has eliminated all higher or more inward possibilities.

But, you know, that just begs the question-what role can I really play in all this?