There are three versions of what Kant termed the “categorical imperative,” two of which have become familiar in moral discussions. The imperatives are “categorical” in the sense that they are binding regardless of what an agent desires. They are contrasted with “hypothetical” imperatives, which take the form of a conditional: If you desire to see a play in London, then you have a reason to head to the airport with a credit card.
The first and most commonly employed version of the categorical imperative is: persons should be treated in such a way that is not incompatible with treating them as ends in themselves (as intrinsically valuable). So, you may “use” a person – as when you use a computer specialist to fix your computer – as long as you are not treating the person with disrespect or as valueless.
According to a second version of the imperative, when you act, you act in accordance with a maxim. For example, in walking across the grass on campus, I am operating on the maxim that if I need to grab lunch before class and the easiest route to do this is to walk on the grass, then I can walk on the grass. In a Kantian framework, we should then ask, ” can one will that this maxim be a universal law?” In other words, would it be ok if everyone walked across the grass if it is the quickest way to get lunch? One should only act on these universalizable maxims. Intuitively, this second version of the categorical imperative raises the question: what if everyone operated with your moral compass?