The Formula of Humanity and Respect for Persons

Kant introduces the second major formulation of the categorical imperative, the Formula of Humanity, at Academy edition page 4:429 of the Groundwork: "act in such a way that you treat humanity, whether in your own person or in the person of any other, always at the same time as an end and never merely as a means." Here "humanity" (Menschheit) denotes not the biological human species but rational nature as such — the capacity for autonomous, rational self-legislation that Kant takes to be the distinguishing feature of persons as opposed to mere things. Because rational beings can set and pursue their own ends according to principles they give themselves, Kant argues they possess a special, non-instrumental status that mere objects lack: a hammer or a sum of money has value only relative to some further purpose, but a rational agent has value simply in being the kind of being capable of purposive, self-directed action.