Hey Doug
I would agree it can't be taught or learned.
As far as teaching i don't think it can be taught, it can be learned it is just very difficult like you said hour's and hour's of training.
I think the reactions can become instinctual after hours and hours of training,
Once you do something once it is no longer instinctual, It then become's a learned response, because if something doesn't work once we change(learn) what we did wrong and attempt to do it again the right way so we use our brain and remember how to do/not do it, and it become's a quicker response as we are able to recall it faster through repetition.
i.e. muscle memory
I am not a believer in "muscle memory" your brain remember's and transmit's it to the muscle, so if you are incapable of thinking and seeing what is happening your in trouble.
I think of a batter "deciding" to swing or not against a 90mph fastball.
That is pretty much it he "decide's" whether he will be able to hit the ball or not, it is a concious response to the stiminlus recieved by the brain in a split second.
the goal for a martial artist is to recognize success at moving Indes when it does naturally happen and hopefully it begins to occur more frequently.
We have to think about what is going on in our drills and sparring and start to
concentrate on the timing and distance and the phyiscal movement.
Therer is nothing mystical about any of this it is as simple as good concentration in drill's and sparring to accustom ourselve's to as many situation's as we can and learn to learn how to respond in/to those and similar situation, that is what the principle's/technique's do is give us solution's for alot of situation's we have to learn to apply them correctly at the right time i.e. Indes.
Jeff