Natural science physics contains in itself synthetical judgments a priori, as principles. ... Space then is a necessary representation a priori, which serves for the foundation of all external intuitions.
Immanuel KantNo 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.
Immanuel KantExperience without theory is blind, but theory without experience is mere intellectual play.
Immanuel KantThere will always be some people who think for themselves, even among the self-appointed guardians of the great mass who, after having thrown off the yoke of immaturity themselves, will spread about them the spirit of a reasonable estimate of their own value and of the need for every man to think for himself.
Immanuel Kant