Today in English class we were shown a list of "moral developments" that seemed to progress linearly - how people determine what is moral when they are 5, and how they determine this when they are 40.
At lunch, my friend said, "I think it is silly to say there are developments of morality".
I replied, "No, they were not developments of morality, but developments how we DETERMINE what is moral. You cannot develop morality because there IS only one true answer to what is moral and what isn't. The list was just showing how people differ in the way they DETERMINE whether something is moral or not."
My friend replied that there is NOT only one true answer to what is moral and what is not - that everyone has "his/her own" set of moral values, and there is not any set that is more correct than another, that I was just biased for thinking so. (In other words, she claims that although murder might seem immoral to me, this does not mean that is IS immoral, only that is is immoral by my moral standards. Nothing IS or ISN'T immoral- it's all opinion, according to her).
Do ethicists think about whether or not there is one true set of moral values, or whether it is all a personal opinion? What is the accepted view (if any)?