We can only penetrate the rind of the earth.

To be and to think are one and the same for us.

He [man] abuses equally other animals and his own species, the rest of whom live in famine, languish in misery, and work only to satisfy the immoderate appetite and the still more insatiable vanity of this human being who, destroying others by want, destroys himself by excess.

In general, the more one augments the number of divisions of the productions of nature, the more one approaches the truth, since in nature only individuals exist, while genera, orders, and classes only exist in our imagination.

The sublime can only be found in the great subjects. Poetry, history and philosophy all have the same object, and a very great object-Man and Nature. Philosophy describes and depicts Nature. Poetry paints and embellishes it. It also paints men, it aggrandizes them, it exaggerates them, it creates heroes and gods. History only depicts man, and paints him such as he is.

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.

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.