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

Thought can be so seductive and hypnotic that it absorbs your attention totally, so you become your thoughts.

An understanding of the natural world is a source of not only great curiosity, but great fulfilment.

The greatest deception men suffer is from their own opinions.

It is the mark of an educated mind to be able to entertain a thought without accepting it.

A house is not a home unless it contains food and fire for the mind as well as the body.

It takes a great man to be a good listener.

The most courageous act is still to think for yourself. Aloud.

The secret of life, though, is to fall seven times and to get up eight times.

The greatest of wealth is the richness of the soul.

The impossible could not have happened, therefore the impossible must be possible in spite of appearances.

The greatest pride, or the greatest despondency, is the greatest ignorance of one's self.

We never see ourselves as others see us.

Courage is resistance to fear, mastery of fear - not absence of fear.

Yesterday is but today's memory and tomorrow is today's dream.

The first thing you'll have to do, is the last thing you wished.

Let him who would move the world first move himself.

Don't take tomorrow to bed with you.

Thoughts without content are empty, intuitions without concepts are blind.

A single lie destroys a whole reputation of integrity.

Do your little bit of good where you are; it's those little bits of good put together that overwhelm the world.