Until philosophers are kings, or the kings and princes of this world have the spirit and power of philosophy, and political greatness and wisdom meet in one, and those commoner natures who pursue either to the exclusion of the other are compelled to stand aside, cities will never have rest from their evils - no, nor the human race, as I believe - and then only will this our State have a possibility of life and behold the light of day.

Republic. Timaeus. Critias (ed. 1892)