Autores:
  • El que puede, hace. El que no puede, enseña.

    Man and Superman "Maxims for Revolutionists" (1903). A further extension appears in Jacob M. Braude, Speaker's Encyclopedia of Stories, Quotations, and Anecdotes (1955): "Those who can, do; those who can't teach; and those who can't do anything at all, teach the teachers."