Fear is the parent of cruelty.

Where nature is sovereign, there is no need of austerity and self-denial.

Sacrifice is the first element of religion, and resolves itself in theological language into the love of God.

Science rests on reason and experiment, and can meet an opponent with calmness; [but] a creed is always sensitive.

The moral system of the universe is like a document written in alternate ciphers, which change from line to line.

Wild animals never kill for sport. Man is the only one to whom the torture and death of his fellow creatures is amusing in itself.

There is always a part of our being into which those who are dearer to us far than our own lives are yet unable to enter.