To know, is to know that you know nothing. That is the meaning of true knowledge.

The true mystery of the world is the visible, not the invisible.

A thing is not necessarily true because a man dies for it.

The function of education is to teach one to think intensively and to think critically. Intelligence plus character - that is the goal of true education.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.

True terror is to wake up one morning and discover that your high school class is running the country.

Everything is true and not true about everything. That’s one thing I’ve learned.

It's true that nothing in this world makes us so necessary to others as the affection we have for them.

I am persuaded, you will permit me to observe, that the path of true piety is so plain as to require but little political direction.

A slender acquaintance with the world must convince every man that actions, not words, are the true criterion of the attachment of friends.

True friendship is a plant of slow growth, and must undergo and withstand the shocks of adversity, before it is entitled to the appellation.

Not to expose your true feelings to an adult seems to be instinctive from the age of seven or eight onwards.

All sciences are now under the obligation to prepare the ground for the future task of the philosopher, which is to solve the problem of value, to determine the true hierarchy of values.