He who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals.

Look closely. The beautiful may be small.

Every man is to be respected as an absolute end in himself; and it is a crime against the dignity that belongs to him as a human being, to use him as a mere means for some external purpose.

Nature even in chaos cannot proceed otherwise than regularly and according to order.

Genius is the ability to independently arrive at and understand concepts that would normally have to be taught by another person.

There will always be some people who think for themselves, even among the self-appointed guardians of the great mass who, after having thrown off the yoke of immaturity themselves, will spread about them the spirit of a reasonable estimate of their own value and of the need for every man to think for himself.

Notion without intuition is empty, intuition without notion is blind.