A positive attitude is something everyone can work on, and everyone can learn how to employ it.

Perfection is not attainable, but if we chase perfection we can catch excellence.

We are going to have peace even if we have to fight for it.

To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.

Genius always finds itself a century too early.

Human behavior flows from three main sources: desire, emotion, and knowledge.

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

Success is never final, failure is never fatal. It's courage that counts.

The true sign of intelligence is not knowledge but imagination.