All thought must, directly or indirectly, by way of certain characters, relate ultimately to intuitions, and therefore, with us, to sensibility, because in no other way can an object be given to us.
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.
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.
No state at war with another state should engage in hostilities of such a kind as to render mutual confidence impossible when peace will have been made.
Enlightenment is man's emergence from his self-imposed immaturity...No thing is required for this enlightenment.. .except freedom; and the freedom in question is the least harmful of all, namely, the freedom to use reason publicly in all matters.
Man desired concord; but nature knows better what is good for his species; she desires discord. Man wants to live easy and content; but nature compels him to leave ease... and throw himself into roils and labors.