It is in the nature of things that joy arises in a person free from remorse.

Look deep into nature, and then you will understand everything better.

Nature knows no indecencies; man invents them.

Sex is part of nature. I go along with nature.

To get the full value of a joy you must have somebody to divide it with.

He who is not content to look, like a savage, at the phenomena of nature as disconnected, cannot any longer believe that man is the work of a separate act of creation ... Man is the co-descendant with other mammals of a common progenitor.