If an offender has committed murder, he must die. In this case, no possible substitute can satisfy justice. For there is no parallel between death and even the most miserable life, so that there is no equality of crime and retribution unless the perpetrator is judicially put to death.

An action is essentially good if the motive of the agent be good, regardless of the consequences.

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.

Every human being should always be treated as an end and never as a mere instrument.

In all judgements by which we describe anything as beautiful, we allow no one to be of another opinion.

I feel a complete thirst for knowledge and an eager unrest to go further in it as well as satisfaction at every acquisition. There was a time when I believed that this alone could constitute the honor of mankind, and I had contempt for the ignorant rabble who know nothing.

With men, the state of nature is not a state of peace, but war.