My finest student? A young man, physically perfect. To look upon him was to see a duellist by any other measure. His discipline was a source of awe; his form was elegance personified. He could snuff a dozen candles in successive lunges, each lunge identical to the one preceeding it. He could spear a buzzing fly. Within two years I could do nothing more for him for he had passed my own skill.
I was, alas, not there to witness his first duel, but it was described to me in detail. For all his talent, his perfection of form, for all his precision, his muscle memory, he revealed one and only one flaw.
He was incapable of fighting a real person. A foe of middling skill can be profoundly dangerous, in that clumsiness can surprise, ill-preparation can confound brilliant skills of defence. The very unprdictability of a real opponent in a life and death struggle served my finest student with a final lesson.
It is said the duel lasted a dozen heartbeats. From that day foreward, my philosophy of instruction changed. Form is all very well, repetition ever essential, but actual blood-touch practice must begin within the first week of instruction. To be a duellist, one must duel. The hardest thing to teach is how to survive.
– A beautiful passage by Steven Erikson.

“Learn by doing” I say.