What are the key features of Kantian deontology and what problems do they pose?

Deontological ethical theories are rule based with strict ideas of right and wrong. Kant considered humans to be autonomous beings, capable of reason and thereby able to construct and impose their own ethical theory without any appeal to God. This essay will discuss three main characteristics of Kant's ethical theory - namely, the universal maxim, the categorical imperative and the importance of a good will. Firstly, Kant's deontology is a non-consequentialist ethical theory; by that, it is the motive behind an action, not the outcome, that determines whether it is good or bad. Kant points out that we are incapable of knowing the outcome of all of our decisions and acknowledges that there is a lot beyond our control - as such, we must construct an ethics that judges actions by the intention behind it. The main problem with non-consequentialist moral theories ,however, is the fact that we have no means of ensuring whether an individual's intention - making any justice system very challenging. Secondly, Kant insists that we must only have moral laws that can have a universal application. This is presented in the form of the categorical imperative that instructs to,"Act only in accordance with that maxim through which you can at the same time will that it become a universal law." Once again, this feature is to ensure the practicality of Kantian ethics - take for example the maxim of lying: if everyone was to lie, there would be no basis for truth. Similarly, the possible maxim "kill everyone" would result in there being no society. Nonetheless the categorical imperative is limited by its very arbitrariness: there are plenty of things we could will universally without contradiction, but this doesn't mean we ought to make them moral laws. For example we could universally will that everyone should wear yellow on Wednesdays, but that doesn't make it morally binding.