The ideal of the supreme being is nothing but a regulative principle of reason which directs us to look upon all connection in the world as if it originated from an all-sufficient necessary cause.

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?

Nature does nothing in vain, and in the use of means to her goals she is not prodigal.

Always treat people as ends in themselves, never as means to an end.

Upon the solution of this problem, or upon sufficient proof of the impossibility of synthetical knowledge a priori, depends the existence or downfall of metaphysics.

The business of philosophy is not to give rules, but to analyze the private judgments of common reason.

Human beings are never to be treated as a means but always as ends.