Therefore, to escape these "irrational and emotional" inclinations, human beings should duty bound to behave morally according to certain rules (Thiroux, 2001). .
Two of the most important principles of Kant's theory are the Categorical Imperative and the Practical Imperative. The Categorical Imperative asserts that in order for a rule to be moral, it must be universalizable; that is, the rule must be applicable to all people, not just to one person in a particular situation. The Practical Imperative states that no human being can ever be used as a means to an end. Each person is considered an end into himself (Thiroux, 2001) and the rights of every human are acknowledged and inviolable (Wofford College online, 1997). The Practical Imperative is one of deontology's greatest strengths. It would be very difficult to argue that indeed, human beings can and should be used as means to another's happiness or success. .
The third and final theory that will discussed here is Ross's theory of Prima Facie Duties. Prima Facie duties are duties which must be "obeyed in a general way before any other considerations enter into the picture" (Thiroux, 2001). Ross gave examples of these duties such as: fidelity, justice, beneficence and nonmaleficence, but did not give all of the prima facie duties, nor did he rank them. Instead, he believed that human beings would know intuitively which duties were prima facie and which prima facie duties should be first taken into consideration when making our ethical choices. Therefore, in making an ethical decision in which two prima facie duties conflict, one would be required to act based on the strongest, or most important duty. However, from person to person, these rankings could be entirely different. How then, do we judge which decisions are right and which are wrong? This is one of the greatest weaknesses of the theory. In fact, The Internet Encyclopedia of Philosophy (2001) states that deontological ethics in general, and this author feels that Ross's theory in particular, rests too heavily on "spontaneous moral intuition".