Nothing is done. Everything in the world remains to be done or done over. The greatest picture is not yet painted, the greatest play isn't written, the greatest poem is unsung. There isn't in all the world a perfect railroad, nor a good government, nor a sound law. Physics, mathematics, and especially the most advanced and exact of the sciences are being fundamentally revised. . . Psychology, economics, and sociology are awaiting a Darwin, whose work in turn is awaiting an Einstein.