Keep the ass to the chair. Everything has been thought before, but the problem is to think of it again. Mathematics has no symbols for confused ideas.
All models are wrong but some are useful.
The paradox is now fully established that the utmost abstractions are the true weapons with which to control our thought of concrete fact. Lerner Life can only be understood backwards, but it must be lived forwards. Krugman Theories are testable where they are least needed, and are not testable where they are most needed. If you torture the data long enough, Nature will confess. Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes.