We must never make experiments to confirm our ideas, but simply to control them.

Man can learn nothing unless he proceeds from the known to the unknown.

But while I accept specialization in the practice, I reject it utterly in the theory of science.

A man of science rises ever, in seeking truth; and if he never finds it in its wholeness, he discovers nevertheless very significant fragments; and these fragments of universal truth are precisely what constitutes science.

The eloquence of a scientist is clarity; scientific truth is always more luminous when its beauty is unadorned than when it is tricked out in the embellishments with which our imagination would seek to clothe it.

The investigator should have a robust faith - and yet not believe.

First causes are outside the realm of science.