The categorical imperative (German: kategorischer Imperativ) is the central philosophical concept in the deontological moral philosophy of Immanuel Kant. Introduced in Kant's 1785 Groundwork of the Metaphysics of Morals, it may be defined as a way of evaluating motivations for action.
According to Kant, human beings occupy a special place in creation, and morality can be summed up in an imperative, or ultimate commandment of reason, from which all duties and obligations derive. He defined an imperative as any proposition declaring a certain action (or inaction) to be necessary.Kant, unlike for example Mill, believed that certain types of actions (including lying) were absolutely prohibited, even in cases where the action would bring about more happiness than the alternative.
I bet you anything you like that Immanuel Kant never, ever had a mother recovering in hospital from a hip operation and a father with Alzheimer's he had to keep reassured.
This weekend I have been channelling Fibber McGee at the expense of Kant.