categorical imperative

a command which expresses a general, unavoidable requirement of the moral law. Its three forms express the requirements of universalizability, respect and autonomy. Together they establish that an action is properly called 'morally good' only if (1) we can will all persons to do it, (2) it enables us to treat other persons as ends and not merely as the means to our own selfish ends, and (3) it allows us to see other persons as mutual law-makers in an ideal 'realm of ends'.