Leonardo Da Vinci
"All our knowledge has its origins in our perceptions.""It had long since come to my attention that people of accomplishment rarely sat back and let things happen to them. They went out and happened to things.""Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.""Nothing strengthens authority so much as silence.""He who is fixed to a star does not change his mind.""Learning never exhausts the mind.""It's easier to resist at the beginning than at the end.""In rivers, the water that you touch is the last of what has passed and the first of that which comes; so with present time.""Time stays long enough for anyone who will use it.""I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do.""Who sows virtue reaps honor."