And he means "not a complete discipline' by the fact that no one is supposed to define it
I totally disgaree with that. David Also does gymnastics, acrobatics, and martial arts (I'm sure among other things).
By "not a complete discipline" I think he means "not a complete discipline". In that if all you did was practice movement from A to B, then all you would be good at is getting somewhere fast. That's not nearly complete, look at methode naturalle, look at reading, at life safety skills, at emt and first responder skills, look at olympic weightlifting, grappling, negotiation. I've said many times before, what good is getting somewhere fast if you're not prepared to be useful when you get there?
What's really disturing to me is all the hypocrites clilngin tightly to David's words and saying that you should be out practicing, not clinging tightly to David's words. Yes, there are things we can learn from him, he is a great and accomplished human being in certain aspects, in others there are people far more accomplished, this is natural, especially when one is a pioneer in a certain field. Gymnasts are way better at gymnastics. I'm guessing a dedicated 10 years martial artist is generally more skilled and knowledgable in martial arts than he is. A doctor is better trained in paramedic skills than he is. And That's all OK.
In my opinion, it is best not to try to become like David, or to "follow" David, but instead try to use what he has learrned to lead your own direction, your own path.