The more the division of labor and the application of machinery extend, the more does competition extend among the workers, the more do their wages shrink together.

出自北齐·颜之推《颜氏家训·省事》。很多的事情一起做，可能做好的却很少，还不如专心致志的做一件事情。

Internal mental events are irrelevant to the scientific study of behavior.

You can't change the past, but you can ruin the present by worrying about the future.