Traditional ethics developed mainly out of the teachings of Plato and Aristotle. Even though their views greatly differ; they collectively constitute the basis of traditional ethics. According to Plato his theory of Form, which are unnatural and immaterial, explain morals. Plato held that the ultimate Form was Good. He postulated that the only way to partake in reality is to seek this ultimate Form, Good. Aristotle was the first great ethical naturalist. He believed that morals are nothing more than natural responses governed by natural laws. For Aristotle the highest aim of humans is to seek happiness; however not at the expense of everything else. Aristotle used the term “mean between extremes” to describe his understanding of morals. “Mean between extremes” can be seen in the example of courage. Courage is a “mean between extremes” of too much fear and not enough fear.
Modern ethics was formed mainly from the writings of G.E. Moore. Moore held that good cannot be analyzed into less complex structures; that what is good is just good. He also believed that it was our job to seek this non-Form, unnatural good.
As Aristotle inadvertently coined the term metaphysics, Moore also coined the term metaethics. As physics is the study of matter and metaphysics is the study of what is matter and why does in matter to us; metaethics is not the study of what actions are good or bad, but what is good and bad in the first place.
Bruder, K., & Moore, B. N. (2002). Philosophy: The power of ideas (6th ed.). Boston: McGraw-Hill Higher Education.