"If you treat an individual as he is, he will remain as he is. But if you treat him as if he were what he ought to be and could be, he will become what he ought to be and could be."

"All theory, dear friend, is gray, but the golden tree of life springs ever green."

"Every day we should hear at least one little song, read one good poem, see one exquisite picture, and, if possible, speak a few sensible words."

"The beautiful is a manifestation of secret laws of nature, which, but for this appearance, would have remained hidden from us."

"Man sieht nur, was man weiß."