Marriage...is the union of two people of different sexes with a view to the mutual possession of each other's sexual attributes for the duration of their lives.
Reason in a creature is a faculty of widening the rules and purposes of the use of all its powers far beyond natural instinct; it acknowledges no limits to its projects. Reason itself does not work instinctively, but requires trial, practice, and instruction in order gradually to progress from one level of insight to another.
Aus so krummen Holze, als woraus der Mensch gemacht ist, kann nichts ganz Gerades gezimmert werden. Out of the crooked timber of humanity, no straight thing can ever be made.
Human reason has this peculiar fate that in one species of its knowledge it is burdened by questions which, as prescribed by the very nature of reason itself, it is not able to ignore, but which, as transcending all its powers, it is also not able to answer.
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.
Beneficence is a duty; and he who frequently practices it, and sees his benevolent intentions realized comes, at length, really to love him to whom he has done good.
Freedom is independence of the compulsory will of another, and in so far as it tends to exist with the freedom of all according to a universal law, it is the one sole original inborn right belonging to every man in virtue of his humanity.
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.