„By a tranquil mind I mean nothing else than a mind well ordered.“

— Marcus Aurelius
„nothing contributes so much to tranquilize the mind as a steady purpose“
— Mary Wollstonecraft Shelley
„[P]eace of soul implies tranquillity of order, with material things ordered to the body, the body to the soul, the personality to neighbor and to God. Peace of mind is subjective tranquillity — a narrower thing. It requires great moral effort to attain peace of soul, but even those who are indifferent to right and wrong sometimes achieve peace of mind“
— Fulton J. Sheen
„Nothing contributes so much to tranquillize the mind as a steady purpose- a point on which the soul can focus its intellectual eye“
— Mary Wollstonecraft Shelley
„It is in your power to withdraw yourself whenever you desire. Perfect tranquility within consists in the good ordering of the mind, the realm of your own.“
— Marcus Aurelius
„I mean, I have the feeling that something in my mind is poisoning everything else.“
— Vladimir Nabokov
„The only means of strengthening one's intellect is to make up one's mindabout nothing -- to let the mind be a thoroughfare for all thoughts.“
— John Keats
„I feel my heart glow with an enthusiasm which elevates me to heaven, for nothing contributes so much to tranquilize the mind as a steady purpose — a point on which the soul may fix its intellectual eye.“
— Mary Wollstonecraft Shelley