What is the categorical imperative

The categorical imperative is the bedrock of Kant's ethics, and is key to understanding what the basis of deontological duty is. Kant describes - or formulates - the categorical imperative in a number of ways, though it is important to remember that these formulations are for Kant sides of the same coin. The simplest formulation is the 'means-end' formulation, which claims that since all humans are ontologically distinct rational beings, there is a basic duty to treat them as ends in their own right, not as means to an end. To articulate this ethical position in relation to lying, the telling of a lie is forbidden by Kant's deontology because it treats the lied-to person as a means to your own ends. The more complete formulation, the so-called 'maxim of universalizability' is the imperative to only do those things which you would will to be a 'universal law' - that you would want everyone to do at all times. To return to the example of lying, the maxim of universalizability forbids lying not merely because we would not desire everyone to lie at all times, but because - Kant claims - the very notion implies a logical contradiction. Lying for Kant is an act defined by its non-universality, in order for a lie to be a lie it must be disguised as the sincere truth. The categorical imperative states that since you could not will your lying to be a universal law, since that law implies a contradiction in terms, you have a duty not to lie.