"Begging the question" is a debating fallacy, where you make a statement that has some assumptions in it. The assumptions are easy to miss and if you don't call the person on it the debate (or chain of logic) will go to a nice, logical conclusion...and be entirely based on a false premise. What this means in the world of self-defense is that it is easy to teach things that make sense, but don't work.
In "Meditations on Violence" I mentioned instructors who extolled the 'eyes of the tiger' basically saying that you would do very well in a fight if you could get into the predator mindset. That's a perfect example of begging the question. That mindset works very well... provided you can get there. How?
Practicing in any given mindset is not the skill (and as far as I can tell doesn't even help you) of getting to that mindset, especially under assault. Going full-bore offensive works tactically very often... but getting someone to do it for the first time as a conscious decision is like pulling teeth.
This goes on constantly, especially in a field with so many experts and so little field experience like self-defense. Watch for the word 'just': "If you get attacked from behind, just turn around." Could that little bit of wisdom have come from the mouth of anyone who has been attacked from behind? Even (one I am guilty of) "Just get off line". It is logical. It works. It is easy. There are techniques for it. And yet too many people, people who know better, can't ditch their social programming and wind up fighting eye-to-eye. Just because it is logical and it works, doesn't meant there isn't a deeper question being ignored.
An online VPPG challenge:
In a seminar setting, you don't know what levels of skills you will be dealing with and often (especially at mine) the floors are concrete. You don't know who knows how to breakfall, who doesn't and who thinks they know how to breakfall. Given that environment, can anybody come up with a safe way to practice takedowns, especially the momentum throws?