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

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

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.

Time is the great workman of Nature.

Those who write as they speak, even though they speak well, write badly.

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.