The Categorical Imperative: A Test for Maxims

The categorical imperative is not so much a rule about what to do but a rule about how to do it.  In other words, the categorical imperative provides us the form, or structure, of moral judgments.  According to Kant, an action is only good if the personal rule according to which you perform that action can be make a universal law.  In other words, you should only act in a way such that your personal maxim can become a universal law.

The categorical imperative is categorical insofar as it is how we should act at all times.  Contrast this with a hypothetical duty, which we only have if we have some other goal.  Kant thinks that the categorical imperative shows that we have a perfect duty to keep promises and to preserve our own lives.  In other words, you always have a duty not to break promises and not to kill yourself.  Let's see how the categorical imperative shows that we have a perfect duty to do these things.

In order to see if we have a perfect duty to preserve our own lives, we can ask if we could ever universalize a rule according to which we would kill ourselves.  For example, "It is ok to kill myself because it is good for me."  Kant says that it is contradictory to make such a law universal.  If I kill myself, then there is NO good for me.  There can be nothing good for me when I am dead because I am no longer alive to have things be good or bad for me.  Likewise, if everyone were allowed to kill themselves because it is 'good for them', then we would have a similar problem.  There could be no 'good' for anyone if there is nobody to have things be good for them!  Since we cannot universalize a law that condones suicide, then we have a perfect duty to avoid doing that thing.

The same can be said for promise-breaking.  To make a promise is to commit to do something.  You make this commitment to another person, who accepts your promise as evidence of your commitment.  Now if we tried to universalize "It is ok to break promises", then this would mean that nobody must follow through with their commitments.  If people felt like they could break commitments whenever they wanted, then nobody would believe anybody when they make promises.  So making a promise becomes impossible in itself, since making a promise requires that somebody believes my promise and takes my promise as evidence of my commitment.

In the case of breaking promises and committing suicide, rules that support this behavior become logically impossible if the law is universalized.  In the case of benefiting others and cultivating talents, the case is different.  Laws such as "I will not help other people" or "I will not cultivate my own talents" can be followed universally.  The universal application of the law does not preclude the possibility of its fulfillment.  So it passes the first test of the categorical imperative.  We can universalize the rule.  But would a rational person want to live in such a world?  It seems like so long as a  person wants, say either good things for himself or wants to be benefited by the skills and kindness of others, that it is rationally consistent to also do such things himself.  So while we do not have a perfect duty to help others and cultivate our own talent, we have an imperfect duty to cultivate our own talents and to help others.  In other words, there is a hypothetical imperative to perform these actions insofar as we should do these things to meet some goal we have (e.g., happiness).
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