And one more reason why the phrase "Those who can, do. Those who can't teach." is so wildly off base. The multiplicative impact of an effective teacher is incredible.

Just think of the number of people who who have learned from his videos and have used it gain a deeper understanding, been inspired to learn more, or used it to go and do to exciting things.

The amount of impact he has had by effective and concisely explaining complex topics is incredible.