They tell us what we ought to do. They are, 'The Universal Law', 'Treat humans as ends in themselves' and 'Act as if you live in a Kingdom of Ends'.
'The formula of the Law of Nature' outlines that moral laws must be applied in all situations and all rational beings universally, without exception. If an action is right/wrong for me then it's right/wrong for all other people. .
Secondly, 'Act that you treat humanity, both in your own person and in the person of every other human being, never merely as a means, but always at the same time as an end.' You can never use human beings for another purpose, to exploit or enslave them. Humans are rational and the highest point of creation, and so demand unique treatment. For example, you are standing by train track points. If you do nothing the train will go straight on and will run over a baby who has crawled onto the line. If you alter the points, the train will be diverted because Kant believed that you can never treat people as a means to an end.
Lastly, we should "Act as if you were through your maxim a law-making member of a Kingdom of Ends. You are a law making member of the Kingdom of Ends and so, everyone should act as if they are a law making member.".
Therefore, by acting as a law making member of a Kingdom of Ends we cannot lie. You cannot create a maxim "I may lie as all others lie." Every individual needs to appreciate how significant a part they have to play in establishing moral guidelines and rules.
W.D.Ross revived duty based ethics in his book "The Right and the Good". Ross looks at situations where there maybe two conflicting duties; he states that the most important duty will override the other duty concerned. Ross recognises that when we reflect on our moral convictions they reveal the following called 'Prima Facie' duties. They are fidelity, reparation, gratitude, justice, beneficence, self-improvement and non-maleficence.
