"Nature isn't classical, dammit, and if you want to make a simulation of nature, you'd better make it quantum mechanical, and by golly it's a wonderful problem, because it doesn't look so easy." -- Richard Feynman

"Simulating Physics with Computers", International Journal of Theoretical Physics, volume 21, 1982, p. 467-488, at p. 486 (final words) [0]

[0] https://en.wikiquote.org/wiki/Richard_Feynman#Quotes