“Hang on to your youthful enthusiasms -- you’ll be able to use them better when you’re older.”

“Putting things off is the biggest waste of life: it snatches away each day as it comes, and denies us the present by promising the future. The greatest obstacle to living is expectancy, which hangs upon tomorrow, and loses today. You are arranging what lies in Fortune's control, and abandoning what lies in yours. What are you looking at? To what goal are you straining? The whole future lies in uncertainty: live immediately.”

“Religion is regarded by the ignorant as true, by the wise as false, and by the rulers as useful.”

“Are you surprised, as if it were a novelty, that after such long travel and so many changes of scene you have not been able to shake off the gloom and heaviness of your mind? You need a change of soul rather than a change of climate. [...] Do you ask why such flight does not help you? It is because you flee along with yourself. You must lay aside the burdens of the mind; until you do this, no place will satisfy you.”

“Religion is regarded by the common people as true, by the wise as false, and by rulers as useful.”

“The time will come when diligent research over long periods will bring to light things which now lie hidden. A single lifetime, even though entirely devoted to the sky, would not be enough for the investigation of so vast a subject... And so this knowledge will be unfolded only through long successive ages. There will come a time when our descendants will be amazed that we did not know things that are so plain to them... Many discoveries are reserved for ages still to come, when memory of us will have been effaced.”

“The willing, Destiny guides them. The unwilling, Destiny drags them.”