The Metaphysics of Morals by Immanuel Kant Chapter 2 Page 83

Reason then refers every maxim of the will, regarding it as legislating universally, to every other will and also to every action towards oneself; and this not on account of any other practical motive or any future advantage, but from the idea of the dignity of a rational being, obeying no law but that which he himself also gives.

In the kingdom of ends everything has either value or dignity. Whatever has a value can be replaced by something else which is equivalent; whatever, on the other hand, is above all value, and therefore admits of no equivalent, has a dignity.

Whatever has reference to the general inclinations and wants of mankind has a market value; whatever, without presupposing a want, corresponds to a certain taste, that is to a satisfaction in the mere purposeless play of our