- The Formula of the Universal Law of Nature: "Act as if the maxim of your action were to become through your will a universal law of nature."
- The Humanity Formula: "Act in such a way that you always treat humanity, whether in your own person or in the person of any other, never simply as a means, but always at the same time as an end."
- The Autonomy Formula: "So act that your will can regard itself at the same time as making universal law through its maxims."
- The Kingdom of Ends Formula: "So act as if you were through your maxims a law-making member of a kingdom of ends."
Now, consider the first scenario--the Switch scenario--in the Trolley Problem. The maxim in that situation might be something like the following:
Whenever the lives of four people can be saved by flipping a switch and sacrificing the life of one person, I will do so in order to save the lives of the four.This maxim seems to be able to go through the Kantian decision procedure. In other words, it does not seem to imply a contradiction in conception or a contradiction in the will.
On the other hand, if we think of the Switch scenario in terms of the Humanity formula, then it seems that the maxim fails, i.e., it is not morally permissible to flip the switch, since, by doing so, we would be using one person as a means to an end, i.e, as a means to save the lives of four people.
If this is correct, then the same maxim is both morally permissible, when judged relative to the Universal Law formula, and morally impermissible, when judged relative to the Humanity formula. Does that mean that the four formulations are not equivalent after all?