This paper discusses four main theories; the Aristotelian virtue theory, natural law theory, Kantianism theory and the utilitarianism theory. All the four theories are based on the basic rules of living as human beings. The Aristotelian virtue theory states that as long as someone lives, he/she is obliged to live their life well. It explains that everyone is supposed a virtues life. However, this law is limited in that virtues acts vary from one place to another. The natural law is looked at in three precepts: anything good is that which preserves life while which does not is considered bad, procreating and raising children and pursuing truth and knowledge and preserving and maintaining society. This law also occurs on a double effect principal. Nevertheless, it is complicated to apply the whole natural law compressively since different parts of the law favor different cases and occurrences.
This paper also looks at the Kantianism theory that argues ethics is acting out of sense of responsibility without engaging to any selfish desire but exercising what reason prescribes as the duty. This is a good theory since everyone has a level of reasoning that guides and leads us in doing what we ought to do. According to Kant, that which one will not allow everyone else to engage into is selfish and it should therefore not be done. Finally, the paper looks at the utilitarian theory that explains the acceptable doings in the society is that which has positive effects. Anyone acting according to this theory is supposed to aim at bringing out the best outcome. However, this theory is limited in that whatever that would be considered as a good outcome of an act by one group of people can also be considered wrong by another group of people.