“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.”

The form follows the function.

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.

Hatchery fish have the same colours, but they always seem muted like bad reproductions of great art.

Human reproduction can be a sticky subject ewww! Groaned a chorus of students

The fate of nations is intimately bound up with their powers of reproduction. All nations and all empires first felt decadence gnawing at them when their birth rate fell off.

The social relations which are the basis of the reproduction of the species are founded upon the continuous union of parents in marriage.

The very definition of the real becomes: that of which it is possible to give an equivalent reproduction.

All their reproduction will simply mirror this misapprehension.

The haiku reproduces the designating gesture of the child pointing at whatever it is (the haiku shows no partiality for the subject), merely saying: that!

You’re basically the sum of all the experiences you’ve ever had, and they’re sort of shaken up in you and reproduced in the things you create, and that includes seeing movies.