Felix Adler American educator and social reformer, was one of the creators of the Society for Ethical Culture, a liberal religious movement in the United States and Europe. The motto of the society was "Deed not creed."

Felix Adler was born on Aug. 13, 1851, at Alzey in the Rhineland, Germany. He was the son of a rabbi. The family emigrated to the United States when Felix was 6. Adler graduated from Columbia College, New York, with highest honors in 1870. He prepared for the rabbinate in Berlin and Heidelberg, receiving a doctorate summa cum laude from the latter university in 1873. His exposure to biblical criticism, however, and growing concern with earthly human problems led him to renounce his rabbinical office upon his return to America. He soon became affiliated with the Free Religious Association, a group whose transcendentalist leanings had attracted the aging Ralph Waldo Emerson, and ultimately Adler succeeded the association's founder, Octavius Frothingham, as president. But in 1876 Adler and his friends formed a new group, the Society for Ethical Culture.

The Ethical Culture movement, which eventually spread abroad to London, Berlin, and Vienna, became Adler's main enthusiasm. His major writings expressed the society's philosophy: Creed and Deed (1877), The Religion of Duty (1905), An Ethical Philosophy of Life Presented in Its Main Outlines (1918), and The Reconstruction of the Spiritual Ideal (1924). Drawing upon Immanuel Kant's moral imperative (which stated that a man must treat his fellowmen as ends in themselves, not means), Adler contended that each man achieves individual excellency only through involvement in experiences which develop the excellencies of other men. Adler believed that a man's deeds, rather than his religious creed, are the essence of the religious life. The philosophy of Ethical Culture drew upon Judaism, Christianity, Emersonian transcendentalism, and socialism