Only well-written works will descend to posterity. Fulness of knowledge, interesting facts, even useful inventions, are no pledge of immortality, for they may be employed by more skilful hands; they are outside the man; the style is the man himself.

One can descend by imperceptible degree from the most perfect creature to the most shapeless matter, from the best-organised animal to the roughest mineral.

The style is the man himself.

The discoveries that one can make with the microscope amount to very little, for one sees with the mind's eye and without the microscope the real existence of all these little beings.

The human mind cannot create anything. It produces nothing until having been fertilized by experience and meditation; its acquisitions are the germs of its production.

Nature is the system of laws established by the Creator for the existence of things and for the succession of creatures. Nature is not a thing, because this thing would be everything. Nature is not a creature, because this creature would be God. But one can consider it as an immense vital power, which encompasses all, which animates all, and which, subordinated to the power of the first Being, has begun to act only by his order, and still acts only by his concourse or consent ... Time, space and matter are its means, the universe its object, motion and life its goal.

To write well is to think well, to feel well, and to render well; it is to possess at once intellect, soul, and taste.