The schematicism by which our understanding deals with the phenomenal world ... is a skill so deeply hidden in the human soul that we shall hardly guess the secret trick that Nature here employs.

Reason must approach nature with the view, indeed, of receiving information from it, not, however, in the character of a pupil, who listens to all that his master chooses to tell him, but in that of a judge, who compels the witnesses to reply to those questions which he himself thinks fit to propose. To this single idea must the revolution be ascribed, by which, after groping in the dark for so many centuries, natural science was at length conducted into the path of certain progress.

The function of the true state is to impose the minimum restrictions and safeguard the maximum liberties of the people, and it never regards the person as a thing.

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

Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.

Act only according to that maxim whereby you can at the same time will that it should become a universal law.

The science of mathematics presents the most brilliant example of how pure reason may successfully enlarge its domain without the aid of experience