As I’ve said before, something is subjective if it is mind-dependent in the sense that it is a certain way only in someone’s mind, like an opinion, dream, or figment; and something is objective if it is mind-independent. The two terms are denials of each other. For example, the Grand Canyon is objective–it’s there whether you think so or not–and my thought that chocolate ice cream tastes good is subjective–it tastes good to me in my mind but to others it might taste terrible.
What about morality? Morality has to do with right and wrong, good and evil. For example, someone might say it’s wrong to kill a person and good to tell the truth. Are there things that are right or wrong no matter what anyone thinks about them? Or is morality entirely subjective? Note this is a specific question with carefully defined terms. The question is not whether morality is relative or absolute. I think it’s obviously relative in the sense that it is situation-dependent: it can be both right and wrong to kill a person depending on the circumstances, for example. Contrast a killing necessary to protect the innocent with the brutal murder of a total stranger on a whim.
Consider the statement (T) it is wrong to torture and rape a little girl for fun. I would agree that it’s wrong, as I’m sure you would. Is it objectively or subjectively so? I believe that upon a moment’s reflection it becomes obvious that it is objectively evil. It doesn’t matter if the person commiting the crime thinks it’s good. It doesn’t matter if anyone else or everyone, for that matter, thinks it’s good. They would be wrong. My intuition tells me this, and it’s very strong, as it is with most people once they’ve properly grasped the question being asked. There are at least some things that are truly good or evil independently of the mind.
In my experience, people become skeptical when you appeal to intuition, more than they have any right to be. Consider the statement (H) I have a head. How sure are you that you have one? For all you know, you may be a brain in a vat of chemicals being electrically stimulated by a mad scientist to believe you have a body. Skepticism about intuition leads to skepticism about our most basic beliefs. It’s perfectly rational to believe you have a head. It is not arbitrary and dogmatic but based on epistemological principles. We believe H based on our intuitions and the principle that when forced to choose between two propositions, we should reject the one we are less sure of. Of course, it’s possible I don’t in fact have a head. But possibilities are cheap, and there aren’t any good reasons to think I really am a brain in a vat, or at least none with stronger intuitive warrant than the belief I have a head!
I think the belief that T is objective is similar. I’m pretty darn sure it’s not just a matter of fashion that torturing and raping a little girl for fun is bad. Suppose everyone were brainwashed into believing that it’s good. Would it be good or bad? I’m nearly as sure the act would still be evil as I am that I have a head. We seem to apprehend an external moral realm in much the same way we perceive the external world of physical objects. Why doubt this apprehension before being given a defeater? In fact, I think it’s likely any argument against T‘s being objective will have premises such that one is less sure of them than he is of the beliefs he’s being asked to give up. This is the problem with arguments for unpleasant conclusions. The more unpleasant the conclusion, the heavier the burden the argument must shoulder.