> he presented his answer in the form of a set of partial differential equations. To a physicist this may seem natural, but to a computer designer, treating a set of boolean circuits as a continuous, differentiable system is a bit strange. Feynman's router equations were in terms of variables representing continuous quantities such as "the average number of 1 bits in a message address." I was much more accustomed to seeing analysis in terms of inductive proof and case analysis than taking the derivative of "the number of 1's" with respect to time. Our discrete analysis said we needed seven buffers per chip; Feynman's equations suggested that we only needed five. We decided to play it safe and ignore Feynman.

I always felt it strange that people discount the value of calculus, but maybe it is just that most professionals really don't understand calculus that well? It is really useful for so many things, and if you are good at understanding data and how to properly approximate things then you come up with magical solutions to otherwise intractable problems with it.