At high school, I had a sports teacher who was very good at teaching people how to do things. One day my sports class was in the gym and a good friend of mine, Pam, was on the big trampoline. I was standing waiting for my turn when this sports teacher came up and offered to teach Pam how to do more than simply jump up and down. And Pam enthusiastically agreed. So she stood beside the trampoline, giving Pam instructions and taking her through a series of steps that lead up to Pam being able to do a mid-air summersalt. It was really quite amazing to see how knowing the right instructions made it easily possible for Pam to progress. And then the sports teacher made the interesting comment that she had only ever learnt the theory, she had never actually done it on a trampoline. Our teacher knew the theory but only Pam knew the trampolining as only she had actually done it.