We must always change, renew, rejuvenate ourselves; otherwise, we harden.

One should not search for anything behind the phenomena. They themselves are the message.

Nature has neither core nor skin: she’s both at once outside and in.

A man's foibles are what makes him lovable.

It has been said that figures rule the world. Maybe. But I am sure that figures show us whether it is being ruled well or badly.

It is easier to perceive error than to find truth, for the former lies on the surface and is easily seen, while the latter lies in the depth, where few are willing to search for it.

Nature is, after all, the only book that offers important content on every page.