Ethical relativism is the position that there are no moral absolutes, no moral right and wrongs. Instead, right and wrong are based on social norms. Such could be the case with "situational ethics," which is a category of ethical relativism. At any rate, ethical relativism would mean that our morals have evolved, that they have changed over time, and that they are not absolute.
One advantage of ethical relativism is that it allows for a wide variety of cultures and practices. It also allows people to adapt ethically as the culture, knowledge, and technology change in society. This is a good and valid form of relativism.
The disadvantage of ethical relativism is that truth, right and wrong, and justice are all relative. Just because a group of people think that something is right does not make it so. Slavery is a good example of this. Two hundred years ago in America, slavery was the norm and morally acceptable. Now it is not.
Relativism also does not allow for the existence of an absolute set of ethics. Logically, if there are no absolute ethics, then there can be no Divine Absolute Ethics Giver. Requiring an absolute set of ethics implies an Absolute Ethics Giver, which can easily be extrapolated as being God. This would be opposed to ethical relativism. Therefore, ethical relativism would not support the idea of an absolute God, and it would exclude religious systems based upon absolute morals; that is, it would be absolute in its condemnation of absolute ethics. In this, relativism would be inconsistent, since it would deny beliefs of absolute values.
Furthermore, if ethics have changed over time, there is the problem of self-contradiction within the relativistic perspective. 200 years ago slavery was socially acceptable and correct. Now it is not. There has been a change in social ethics in America regarding this issue. The problem is that if slavery becomes acceptable again in the next 200 years, who is to say if it is right or wrong? We would have a contradictory set of right and wrong regarding the same issue. To this I ask the question, does truth contradict itself? (But this gets into the discussion of the nature of truth.)
Within ethical relativism, right and wrong are not absolute and must be determined in society by a combination of observation, logic, social preferences and patterns, experience, emotions, and "rules" that seem to bring the most benefit. Of course, it goes without saying that a society involved in constant moral conflict would not be able to survive for very long. Morality is the glue that holds a society together. There must be a consensus of right and wrong for a society to function well. Ethical relativism undermines that glue.
It seems to be universal among cultures that it is wrong to murder, to steal, and to lie. We see that when individuals practice these counterproductive ethics, they are soon in prison and/or punished. Since ethics are conceptual in nature, and there are some ethics that seem to transcend all cultures (be true for all societies), I conclude that there is a transcendent God who has authored these ethics -- but that is another discussion.
I do not believe that the best ethical patterns discovered by which societies operate (honesty, fidelity, truth, no theft, no murder, etc.) are the product of our biological makeup or trial and error. As a Christian, I see them as a reflection of God’s very character. They are a discovery of the rules God has established by which people best interact with people, because He knows how He has designed them. The 10 commandments are a perfect example of moral absolutes and have yet to be improved upon. They are transcendent; that is, they are not dependent on social norms and are always true.
I was once challenged to prove that there were moral absolutes. I took up the challenge with the following argument. I asked the gentleman whether or not there were logical absolutes. For example, I asked if it was a logical absolute that something could exist and also not exist at the same time. He said no, that it was not possible. Another example is that something cannot bring itself into existence. To this he agreed that there were indeed logical absolutes. I then asked him to explain how logical absolutes can exist if there is no God. I questioned him further by asking him to tell me how in a purely physical universe logical absolutes, which are by nature conceptual, can exist. I told him they cannot be measured, put in a test tube, weighed, nor captured; yet, they exist. So, I asked him to please tell me how these conceptual absolute truths can exist in a purely physical universe... without a God. He could not answer me. I then went on to say that these conceptual absolutes logically must exist in the mind of an absolute God, because they cannot merely reside in the properties of matter in a purely naturalistic universe. And since the logical absolutes are true everywhere all the time and they are conceptual, it would seem logical that they exist within a transcendent, omnipresent being. If there is an absolute God with an absolute mind, then he is the standard of all things – as well as morals. Therefore, there would be moral absolutes. To this argument the gentleman chuckled, said he had never heard that argument before, and conceded that it may be possible for moral absolutes to exist.
Of course as a Christian, as one who believes in the authority and inspiration of the Bible, I consider moral absolutes to be real because they come from God and not because they somehow reside in a naturalistic universe or are determined by the whims of mankind.
Ethics are important in society, in the home, and in all interactions. Would you believe me if I started lying to you in this paper? No. You expect me to be fair, honest, logical, and forthright. Can I be that if I believe all ethics are relative?