Two things fill the mind with ever-increasing wonder and awe, the more often and the more intensely the mind of thought is drawn to them: the starry heavens above me and the moral law within me... Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.

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?

I assert that, in any particular natural science, one encounters genuine scientific substance only to the extent that mathematics is present.

It is never too late to become reasonable and wise.

God put a secret art into the forces of Nature so as to enable it to fashion itself out of chaos into a perfect world system.

All our knowledge begins with the senses...

Freedom is the alone unoriginated birthright of man, and belongs to him by force of his humanity; and is independence on the will and co-action of every other in so far as this consists with every other person's freedom.