The only objects of practical reason are therefore those of good and evil. For by the former is meant an object necessarily desired according to a principle of reason; by the latter one necessarily shunned, also according to a principle of reason.

The more we come in contact with animals and observe their behaviour, the more we love them, for we see how great is their care of the young.

Sincerity is the indispensable ground of all conscientiousness, and by consequence of all heartfelt religion.

But although all our knowledge begins with experience, it does not follow that it arises from experience.

A man who has tasted with profound enjoyment the pleasure of agreeable society will eat with a greater appetite than he who rode horseback for two hours. An amusing lecture is as useful for health as the exercise of the body.

Often war is waged only in order to show valor; thus an inner dignity is ascribed to war itself, and even some philosophers have praised it as an ennoblement of humanity, forgetting the pronouncement of the Greek who said, 'War is an evil in as much as it produces more wicked men than it takes away.'

Act so as to use humanity, yourself and others, always as an end and never as a means to an end.