In every department of physical science there is only so much science, properly so-called, as there is mathematics.

An action is essentially good if the motive of the agent be good, regardless of the consequences.

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?

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?

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

From such crooked wood as that which man is made of, nothing straight can be fashioned.

There is something splendid about innocence; but what is bad about it, in turn, is that it cannot protect itself very well and is easily seduced.