Vilfredo Pareto...on the lifetime of theories

The logico-experimental sciences are made up of a sum of theories which, like living creatures, are born, live, and die, the young replacing the old, the group alone enduring. As with living beings, the lifetimes of theories vary in length, and it is not always the long-lived ones that contribute most to the advancement of knowledge. Faith and metaphysics aspire to an ultimate, eternal resting place. Science knows that it can attain only provisional transitory states. Each theory fulfills its function, and there is nothing more to ask of it.

- Traite de Sociologie Generale, 1919