Kant’s understanding of good will and duty forms the basis for his moral theory. According to Kant it is only the ‘good will’ which is relevant in moral decisions, regardless of what is desirable. The will is in our control and can exercise pure practical reason to tell us what ‘ought’ to be done. Duty is what the good will aims to fulfil. It is important that duty is done for its own sake and not to bring pleasure of happiness to yourself of others. For example, it is your duty to help those less fortunate than yourself by giving to charity, but you should not do so just to feel good about yourself. It is only moral if you act purely out of duty and are not guided only by emotions.
The categorical imperative is also a crucial part of Kant’s ethical theory. The categorical imperative differs from a hypothetical imperative in that acting according to a hypothetical imperative is only to achieve a particular goal. For example, “if I want to be liked I ought to be kind to people”. A categorical imperative, however, contains no reference to other ends; they are moral commands that do not depend on anything, therefore the statements contains no “ifs” such as “I ought to be kind to people.” These rules are applicable to everyone because they are based on a priori law of reason. An action can be tested as moral by using three basic formulations of the categorical imperative. The first is that you should act only according to a maxim whereby you can will that it should be a universal law, therefore if it would be wrong for someone else to act as you did in a certain situation, it is wrong for you also. Kant uses the example of keeping promises to demonstrate this; if a man borrows money and promises to pay it back even though he is aware that he will not be able to the maxim of his action would be “Whenever I am in need of money, I will borrow and promise to pay it back, though I know that this will not be done.” Clearly, if this was a universal principle then there would be no sense in making promises in the first place, therefore Kant would deem this action to be universally wrong.
The second fundamental principle of the categorical imperative is the formula of end in itself- to treat humanity always as an end rather than solely as a means. By this Kant means that people should not be exploited for selfish gain, as people are rational and independent beings. If we fail to do this we treat ourselves as if we are superior to others. Therefore to be moral we need to value everyone equally. The third formula, the “formula of a kingdom of ends” develops this idea to suggest that everyone should act as if every other person was an “end”, a free, self-ruling agent. We ought to act only by maxims which would harmonize with a possible kingdom of ends, as it is our duty not to act by maxims that are incoherent when we attempt to universalize them. By suggesting that individuals are independent and autonomous, however, Kant does not mean to suggest that everyone can decide on their own morality, but that everyone has the ability to use their pure practical reason to know what is right.