Philosophical knowledge is knowledge which reason gains from concepts; mathematical knowledge is knowledge which reason gains from the construction o… - Immanuel Kant

Handle so, daß du die Menschheit, sowol in deiner Person, als in der Person eines jeden andern, jederzeit zugleich als Zweck, niemals bloß als Mittel brauchest.

The public use of a man's reason must be free at all times, and this alone can bring enlightenment among men...

...Ethical laws cannot be thought of as emanating originally merely from the will of this superior being as statutes, which, had he not first commanded them, would perhaps not be binding, for then they would not be ethical laws and the duty proper to them would not be the free duty of virtue but the coercive duty of law.