“The strong current of abstraction in modern mathematics is in danger of degenerating into sterile dogmatism if it is not revivified from time to time by contact with the reality of applications.”— Richard Courant
“Knowing is not enough; we must apply. Willing is not enough; we must do.”— Johann Wolfgang von Goethe
“The beauty of a theory is that it can be applied to a wide range of phenomena.”— Rudolph A. Marcus
“There is no less invention in aptly applying a thought found in a book, than in being the first author of the thought.”— Robert Boyle
“I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do.”— Leonardo da Vinci
“For to what purpose should a man be a great master of numbers, if he knows not how to apply them to his use?”— William Emerson