The happiness and unhappiness of the rational, social animal depends not on what he feels but on what he does; just as his virtue and vice consist not in feeling but in doing.

Marcus Aurelius Antoninus (121-180 a d): Meditations. ix. 16.

  Man is a noble animal, splendid in ashes and pompous in the grave.

Sir Thomas Browne (1605-1682): Dedication to Urn-Burial. Chap. v.

  Plato having defined man to be a two-legged animal without feathers, Diogenes plucked a cock and brought it into the Academy, and said, "This is Plato's man." On which account this addition was made to the definition,—"With broad flat nails."

Diogenes Laertius (Circa 200 a d): Diogenes. vi.

  They also say that God is an animal immortal, rational, perfect, and intellectual in his happiness, unsusceptible of any kind of evil, having a foreknowledge of the universe and of all that is in the universe; however, that he has not the figure of a man; and that he is the creator of the universe, and as it were the Father of all things in common, and that a portion of him pervades everything.

Diogenes Laertius (Circa 200 a d): Zeno. lxxii.