Omnia apud me mathematica fiunt.

Give me extension and motion and I will construct the universe.

When I consider this carefully, I find not a single property which with certainty separates the waking state from the dream. How can you be certain that your whole life is not a dream?

You just keep pushing. You just keep pushing. I made every mistake that could be made. But I just kept pushing.

The reading of all good books is indeed like a conversation with the noblest men of past centuries who were the authors of them, nay a carefully studied conversation, in which they reveal to us none but the best of their thoughts.

The first precept was never to accept a thing as true until I knew it as such without a single doubt.

The chief cause of human errors is to be found in the prejudices picked up in childhood.