KANT'S ARGUMENT FOR THE CATEGORICAL IMPERATIVE
Hypothetical imperative: If you want X, then you must do Y. (Conditional
command)
Categorical imperative: You must do Z. (Unconditional command)
I.
1. A moral law is universal, and it sometimes conflicts with self-interest.
2. Hypothetical imperatives are not universal, nor do they conflict with self-
interest.
3. Therefore, the moral law must be a categorical imperative.
II.
1. Because it does not aim at the satisfaction of a particular desire, the
categorical imperative has no particular content, but only the form of law.
2. The form of law is universal obligation.
3. Therefore, an action that obeys the categorical imperative is one that is
commanded by a universal law.
4. Therefore, the categorical imperative commands this: Act in such a way that
you would want there to be a universal law that commands everyone to act in
just that way.
III.
1. A person who gives herself a practical rule to follow must have a purpose in
doing so.
2. The purpose or end toward which the categorical imperative aims must be an
ultimate end, not something that is a means to another end.
3. Everything in the world that has a purpose has its purpose given to it by
humans. Only one thing gives itself its own purpose: human (rational) being.
4. Therefore, a human being is an end in itself, something self-determining,
not a mere means to another end. This is the ultimate end toward which the
categorical imperative aims.
5. Therefore, the categorical imperative commands this: treat all humanity,
including yourself, as an end in itself, never as a means only.