Quote Originally Posted by DuncanONeil View Post
I think you have a misunderstanding of discipline.
I doubt that. There are many definitions. Please pay attention to the context of the sentence.

Definition #5c (if that helps.)

Quote Originally Posted by merriam webster
Main Entry: 1dis·ci·pline
Pronunciation: \ˈdi-sə-plən\
Function: noun
Etymology: Middle English, from Anglo-French & Latin; Anglo-French, from Latin disciplina teaching, learning, from discipulus pupil
Date: 13th century
1 : punishment
2 obsolete : instruction
3 : a field of study
4 : training that corrects, molds, or perfects the mental faculties or moral character
5 a : control gained by enforcing obedience or order b : orderly or prescribed conduct or pattern of behavior c : self-control
6 : a rule or system of rules governing conduct or activity