Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at… - Immanuel Kant

Human beings are never to be treated as a means but always as ends.

Act so as to treat humanity, whether in your own person or in that of another, at all times also as an end, and not only as a means.

From this it follows incontestably, that pure concepts of the understanding never admit of a transcendental, but only of an empirical use, and that the principles of the pure understanding can only be referred, as general conditions of a possible experience, to objects of the senses, never to things in themselves…

If the intuition must conform to the nature of the objects, I do not see how we can know anything of them a priori. If, on the other hand, the object conforms to the nature of our faculty of intuition, I can then easily conceive the possibility of such an a priori knowledge.

What can I know? What ought I to do? What can I hope?