Quote by Isaac Newton
"To doubt is to think; to think is to grow."
More from Isaac Newton
"If I have seen further, it is by standing on the shoulders of giants."
"The greatest force in the universe is not gravity, but human potential."
"I can calculate the motion of heavenly bodies, but not the madness of people."
"Nature and nature's laws lay hid in night; God said, Let Newton be! and all was light."