See Persig Zen and the Art of Motorcycle Maintenance on Quality
I believe that the real source of ideas about Quality in this popular book is not Plato but really . . .
PEPPER (Stephen). Concept and Quality. La Salle, Ill., Open Court, 1966.
See Stephen C. Pepper and Chinese Philosophy of Art http://www.thomehfang.com/suncrates6/Stephen%20C.%20Pepper%20and%20Chinese%20Philosophy%20of%20Art2.htm