A professor can never better distinguish himself in his work than by encouraging a clever pupil, for the true discovers are among them, as comets amongst the stars.

Nature does not proceed by leaps.

Nature's economy shall be the base for our own, for it is immutable, but ours is secondary. An economist without knowledge of nature is therefore like a physicist without knowledge of mathematics.

If you do not know the names of things, the knowledge of them is lost, too.

I demand of you, and of the whole world, that you show me a generic character... by which to distinguish between Man and Ape. I myself most assuredly know of none.

A professor can never better distinguish himself in his work than by encouraging a clever pupil, for the true discovers are among them, as comets amongst the stars.

In natural science the principles of truth ought to be confirmed by observation.