The Categorical Imperative

There is therefore but one categorical imperative, namely, this: Act only on that maxim whereby thou canst at the same time will that it should be a universal law.
- Immanuel Kant, Fundamental Principles of the Metaphysics of Morals , translation 1873)

Is there one rule that sums up morality?

Kant expressed his central moral principle in two main ways: l) Treat others as ends always, never as means only; and 2) Always act in such a way that the maxim of your action can be willed by you to be a universal law.

Kant was the first philosopher to understand what a person really is. A person, a self, is part phenomenal (physical, visible, an object of experience) and part noumenal (a self as it is in itself, the true self, a subject of experience). The phenomenal self must obey the natural law of cause- and effect and is therefore not free; the noumenal self we can know nothing about, for it is transcendental-but we must believe it is free, otherwise our moral judgments would be nonsensical.

So we must believe the self is free--free not only in oneself, but also in others. If I believed no other person to be free, I couldn't believe it about myself, either. And so I must treat others as if they are beings with free will and purposes of their own, not as just things-as ends, not means.

To Kant, immorality is illogical-- if I treat others as means only, I cannot logically, consistently, expect to be treated any better myself. And this is why I must be able to "will the maxim of my action to be a universal law": whatever I do, I must ask, should everyone do the same thing in similar circumstances?

For example, if you borrow $5 from me with no intention of paying it back, you are treating me purely as a means of getting $5. You are using me. You should ask, what if everyone did that? That is, what if everyone, when he or she needed money, just made a lying promise to pay it back? In that case there would soon be no lending, no trust, no believing of promises. So there could be no such rule. Such a rule would be logically self-defeating, even self- contradictory.

There are other ways to put Kant's categorical imperative: Treat others as you wish to be treated (that is, as a person, not a thing); and, Don't make an exception of yourself. If you think lying is wrong (and especially for others to lie to you) then you shouldn't lie yourself. But can you think of some action which would clearly be wrong, but not wrong according to Kant's categorical imperative? What if a madman burst into the room with a loaded gun and asked me where you were? Should I tell him the truth, or not?

Bibliography

Kant, Immanuel Critique of Practical Reason, The Liberal Arts Press, Inc., New York, 1962.

Kant, Immanuel. Fundamental Principles of the Metaphsics of Morals, T.K. Abbott translation, The Liberal Arts Press. New York,1949.