“The form follows the function.”

It is not always the magnitude of the differences observed between species that must determine specific distinctions, but the constant preservation of those differences in reproduction.

It is not enough to discover and prove a useful truth previously unknown, but that it is necessary also to be able to propagate it and get it recognized.

All knowledge that is not the real product of observation, or of consequences deduced from observation, is entirely groundless and illusory.

Habits form a second nature.

What nature does in the course of long periods we do every day when we suddenly change the environment in which some species of living plant is situated.

All known living bodies are sharply divided into two special kingdoms, based upon the essential differences which distinguish animals from plants, and in spite of what has been said, I am convinced that these two kingdoms do not really merge into one another at any point.

It is not the organs-that is, the character and form of the animal’s bodily parts-that have given rise to its habits and particular structures. It is the habits and manner of life and the conditions in which its ancestors lived that have in the course of time fashioned its bodily form, its organs and qualities.

Pedantry in learning is like hypocrisy inn religion–a form of knowledge without the power of it.

My best stories come out of nowhere, with no concern for form at all.

Prejudice is a great time saver. You can form opinions without having to get the facts.

I take a cliche and try to organize its forms to make it monumental. The difference is often not great, but it is crucial.

I must always have a clear image of the form of a work before I begin. Otherwise there is no impulse to create.

I have confidence that we can form this kind of national community.

Advice is a form of nostalgia.

Don’t try so much to form your character – it’s like trying to pull open a tight, tender young rose.