"Self-discipline begins with the mastery of your thoughts. If you don't control what you think, you can't control what you do. Simply, self-discipline enables you to think first and act afterwards." Napoleon Hill

A disciplined mind is a sound mind and vice versa. The mind is disciplined because it has been subjected to sound principles and judgement over a period of time and so thinks differently from many others. Regarding issues of common concern and interest, many people, between 85 and over 95% tilt towards one point of view and the remainder 15% and less are often hounded.