"first, he wrote down the question, then he thought very hard, then he wrote down the answer." this is like: Step 1: Start Step 2: ??? Step 3: PROFIT! " he

"first, he wrote down the question, then he thought very hard, then he wrote down the answer." this is like: Step 1: Start Step 2: ??? Step 3: PROFIT! " he didn't place any special importance on his own internal "sketching" models when describing things to others." So the answer was more like: Feynman's priority was to show the most concise derivation, not to show the path he stumbled around to arrive at a result. Indeed I believe most people once they have a rough path to a result, immediately try to simplify it to the crux of the argument before presentation, all the unnecessary assumptions are trimmed off, just like a mathematician tries to find a proof that relies on the least axioms. Sometimes I see people explain how they came up with their result, but I suspect even these detours are often substantially cleaned up before presentation. Others simply no longer remember the original thought process, due to time passing, or because while working out the longwinded original path the simpler shortcut simply hits them. That instant high of a realization also tends to pollute your memory of stumbling towards it. Another problem is that big problems were often in the back of a persons mind for a long time, and before a solution materializes, small insights or even vague associations -that may be seperated by years- ultimately combine, so a sudden insight is often just the last piece, with some of the supporting lemmas never disclosed before (as of seemingly no value when the smaller supporting insights were conceived) Perhaps there is a text somewhere, where Feynman explains how he originally arrived at it, but if so I haven't seen it. I too would like to see it if it is known or ever turns up...