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

Experiment is fundamentally only induced observation.

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.

In the patient who succumbed, the cause of death was evidently something which was not found in the patient who recovered; this something we must determine, and then we can act on the phenomena or recognize and foresee them accurately. But not by statistics shall we succeed in this; never have statistics taught anything, and never can they teach anything about the nature of the phenomenon.

It is what we know already that often prevents us from learning.

The true worth of an experimenter consists in his pursuing not only what he seeks in his experiment, but also what he did not seek.

We must keep our freedom of mind, ... and must believe that in nature what is absurd, according to our theories, is not always impossible.