Abstract

Kant’s Formula of Humanity (FH) is considered by many, Kant included, to be the most intuitively appealing formulation of the categorical imperative. FH tells us that to treat persons with dignity and respect we must always treat them as ends in themselves and never as mere means. One set of issues raised by FH revolves around how FH is to be justified or grounded and how it relates to the other formulations of the categorical imperative. This set of issues, though important, is not our focus here. Instead, we shall focus on a different set of issues: how do we apply or use this formula in practice, that is, how does this principle work as a moral guide to what duties and obligations we have in particular cases? This paper will seek to answer that question by defending an interpretation and rational reconstruction of FH in terms of two subsidiary principles, the Mere Means Principle (MMP), which grounds perfect duties, and the Ends in Themselves Principle (ETP), which grounds imperfect duties. These two principles will then be applied to a number of examples to illustrate how they work.