“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
“The beauty of a theory is that it can be applied to a wide range of phenomena.”— Rudolph A. Marcus
“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
“Knowing is not enough; we must apply. Willing is not enough; we must do.”— Johann Wolfgang von Goethe