True art and true science possess two unmistakable marks: the first, an inward mark, which is this, that the servitor of art and science will fulfil his vocation, not for profit but with self- sacrifice; and the second, an external sign, his productions will be intelligible to all the people whose welfare he has in view.
Leo Tolstoy (2010). “On the Significance of Science and Art”, p.65, The Floating Press
