The minds that rise and become really great are never self-satisfied, but still continue to strive.

First causes are outside the realm of science.

Mediocre men often have the most acquired knowledge. It is in the darker. It is in the darker regions of science that great men are recognized; they are marked by ideas which light up phenomena hitherto obscure and carry science forward.

The first requirement in using statistics is that the facts treated shall be reduced to comparable units.

A great discovery is a fact whose appearance in science gives rise to shining ideas, whose light dispels many obscurities and shows us new paths.

Effects vary with the conditions which bring them to pass, but laws do not vary. Physiological and pathological states are ruled by the same forces; they differ only because of the special conditions under which the vital laws manifest themselves.

Priestley [said] that each discovery we make shows us many others that should be made.