i feel like this is still very true today, esp. in large projects or after a ~week of changes i have to stop and make sure my mental model ("theory of the program") still holds.
Gal Sapir
In 1985 Peter Naur argued that a program is more than just its source code. "Programming As Theory Building" explained how we build theories of the code which help us debug and refactor it but those theories rely on knowledge from outside of the code.
pages.cs.wisc.edu/~remzi/Naur....
