Dr Frank Salmon! Is that you? My professor at University Of Manchester in the mid 1990's who's lectures were both sublime and legendary... I wrote furiously during your lectures...and still remember them fondly... You were a legend! (amongst us students)
20:13 - very important words. Maybe put not in the most correct way but - yes - you have to have the preemtiveness and know the evolution of some field of knowledge, which has been achieved for thousands of years