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

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

In law a man is guilty when he violates the rights of others. In ethics he is guilty if he only thinks of doing so.

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?

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.

Act that your principle of action might safely be made a law for the whole world.

If, like Hume, I had all manner of adornment in my power, I would still have reservations about using them. It is true that some readers will be scared off by dryness. But isn't it necessary to scare off some if in their case the matter would end up in bad hands?