"There is not one single instance of any civilization being spontaneous. There was not a race in the world which became civilised unless another civilised race came and mingled with that race. The origin of civilization must have belonged, so to say, to one or two races who went abroad, spread their ideas, and intermingled with other races and thus civilization spread."

- Swami Vivekananda, "Hints on Practical Spirituality" (Spiritual Breathing, Dec 29, 1899, Los Angeles Home of Truth), Complete Works: Vol 2