Patience is the strength of the weak, impatience is the weakness of the strong.
Enlightenment is man's emergence from his self-incurred immaturity.
Act only according to that maxim whereby you can at the same time will that it should become a universal law.
Only the descent into the hell of self-knowledge can pave the way to godliness.
An action, to have moral worth, must be done from duty.
Thoughts without content are empty, intuitions without concepts are blind.