Man must be disciplined, for he is by nature raw and wild.

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

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

There can be no doubt that all our knowledge begins with experience.

The light dove, in free flight cutting through the air the resistance of which it feels, could get the idea that it could do even better in airless space. Likewise, Plato abandoned the world of the senses because it posed so many hindrances for the understanding, and dared to go beyond it on the wings of the ideas, in the empty space of pure understanding.

If I am to constrain you by any law, it must be one by which I am also bound.

[A ruler is merely] the trustee of the rights of other men and he must always stand in dread of having in some way violated these rights.