Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.

Necessity is the theme and the inventress, the eternal curb and law of nature.

Nature appears to have been the cruel stepmother rather than the mother of many animals.

The body of the earth is of the nature of a fish, a grampus or sperm whale, because it draws water as its breath instead of air.

There is no result in nature without a cause; understand the cause and you will have no need of the experiment.

O mighty and once living instrument of formative nature. Incapable of availing thyself of thy vast strength thou hast to abandon a life of stillness and to obey the law which God and time gave to procreative nature.