I know this thead has been sleeping since mid-July, but I have only just found it.
I have spent a lifetime working with Chemistry, Maths and Physics experts. Many of them PhDs and some professors in their subject. All regarded by us erks as clever clogs.Mostly they can spout the theories and then back it up with practical examples, oftern on the lab. bench.
However Feynmans' knowledge was exceptional. I recall a television program about him, I think in the late 70s where he explained in fairly simple words a particular piece of work he was pursuing and made it clear and enjoyable. He went on to show the maths on the blackboard, his speed of writing was phenomenal, but he went back through it with an explanation of the steps.
When I got to work next morning several of my colleagues had watched, but none would discuss the maths (that included the mathematicians, one of whom was working on high energy physics) and they all agreed that their maths would not take them that far. I felt that most of them were disappointed about their own level of expertise.
I might add that my maths is in a different league altogether; once I get beyond simple Trig. I am totally lost. Algebra is a closed book to me.
Altogether a loss when he died.
Jerry