All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

Time is not an empirical concept. For neither co-existence nor succession would be perceived by us, if the representation of time did not exist as a foundation a priori.

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

Among all nations, through the darkest polytheism glimmer some faint sparks of monotheism.

Always regard every man as an end in himself, and never use him merely as a means to your ends [i.e., respect that each person has a life and purpose that is their own; do not treat people as objects to be exploited].

It is never too late to become reasonable and wise.

Parents usually educate their children merely in such a manner than however bad the world may be, they may adapt themselves to its present conditions. But they ought to give them an education so much better than this, that a better condition of things may thereby be brought about by the future.