An imperative is the form that a command takes. Imperatives are a grammatical category of statements. Examples of imperatives include, "Please don't smoke here.", "Stop being racist.", and "Always act in such a way that your personal rule can be made a universal law." This last imperative is the categorical imperative. To say it is categorical just means to say that it is necessary and universal. We can contrast categorical imperatives with hypothetical imperatives. A hypothetical imperative is one that we need not follow necessarily and universally. We only have a hypothetical duty if there is some other goal we have in mind. For example, if a rational person wants to be happy, then they probably like being benefited by others (rather than have people interrupt their way of life or be harmful towards them). Kant thinks there is an imperfect duty to benefit others if we want to be happy. There is not a categorical imperative to perform this action because it pasts the test of the categorical imperative (it is logically possible to universalize a law that says not to benefit other people). But if we want to be happy, then it seems like the same reasons that we are made happy will also apply to other people. It is rationally consistent to benefit others if you like to be benefited by others.
is also a hypothetical imperative to cultivate your own talents and
skills. Hypothetical imperatives lead to imperfect duties. To say that
we have a hypothetical imperative to cultivate our talents just means
that we have an imperfect duty to cultivate our talents. Imperfect
duties are neither necessary nor universal. Perfect duties, however,
are necessary and universal.
Just as there are two
imperfect duties that Kant talks about, there are also two perfect
duties that Kant talks about. First, there is a perfect duty to
preserve your life. In other words, the categorical imperative would
forbid suicide. If you want to kill yourself because you think it is
good for you, then your will is self-contradictory because if you are
dead, NOTHING is good for you. In order for something to be good for
you, then you must be alive. Second, there is a perfect duty to keep
promises/never to lie.