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.

• Experience without theory is blind, but theory without experience is mere intellectual play.
• It is beyond a doubt that all our knowledge that begins with experience.
• But although all our knowledge begins with experience, it does not follow that it arises from experience.
• It is not God's will merely that we should be happy, but that we should make ourselves happy.
• It is not God's will merely that we should be happy, but that we should make ourselves happy.
• Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.
• Happiness is not an ideal of reason, but of imagination.
• All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?
• What can I know? What ought I to do? What can I hope?
• Happiness is not an ideal of reason, but of imagination.