In most states of society it is the existence of great men which decides even whether there shall be any progress.
 John Stuart Mill, A System Of Logic, Ratiocinative And Inductive (1843). copy citation

Context

“and that if there had been no Christ, and no St. Paul, there would have been no Christianity. The point in which, above all, the influence of remarkable individuals is decisive, is in determining the celerity of the movement. In most states of society it is the existence of great men which decides even whether there shall be any progress. It is conceivable that Greece, or that Christian Europe, might have been progressive in certain periods of their history through general causes only: but if there had been no Mohammed, would Arabia have produced Avicenna or Averroes, or Caliphs of Bagdad or of Cordova?” source