Plato

“Civilization is a race between disaster and education.”
― H.G. Wells

“Upon this first, and in one sense this sole, rule of reason, that in order to learn you must desire to learn, and in so desiring not be satisfied with what you already incline to think, there follows one corollary which itself deserves to be inscribed upon every wall of the city of philosophy: Do not block the way of inquiry.”
― Charles S. Peirce

“Against the disease of writing one must take special precautions, since it is a dangerous and contagious disease.”
― Pierre Abélard, The Letters of Abélard and Héloïse

“Dwell on the beauty of life. Watch the stars, and see yourself running with them.”
― Marcus Aurelius, Meditations