Wisdom is the ability to see the long-run consequences of current actions, the willingness to sacrifice short-run gains for larger long-run benefits, and the ability to control what is controllable and not to fret over what is not. Therefore the essence of wisdom is concern with the future. It is not the type of concern with the future that the fortune teller has; he only tries to predict it. The wise man tries to control it.
- From A Concept of Corporate Planning by Russell L. Ackoff