In my ethics class, we talked about JL Mackie's short essay The Subjectivity of Values. My teacher, while not seeming to be impressed by the first argument I'll go over, did indicate that we could consider the other two as pretty good. I've found that my teacher and I differ pretty greatly on what constitutes a good argument. I'll go over the formulations my teacher presented and critique them here.
Argument from relativity
P1. Moral values vary from culture to culture, from time period to time period, and from class to class in the same society.
P2. Radical differences in normative values cast doubt on the objectivity of moral values.
C. Therefore, there is good reason to think that moral values are subjective.
My first thought about this argument is that it's hard to see how it's even valid. Seems to me that the most we can say from these two premises is C' There is reason to think that moral values are subjective. Why should even radical differences give us good reason to doubt objective morality? It certainly doesn't follow from the premises in a strict literal sense.
Premise one seems to be subtly begging the question for subjectivism. The objectivist would say that moral values don't vary from these cultures, though cultural norms, which may or may not line up with whatever objective morality may exist, could vary in this way. It would be more correct to say that what cultures hold to be the correct moral values may vary from culture to culture, etc.
The objectivist could also say about premise one that it is blatantly false. Though some values may differ from culture to culture, there seem to be some that not only do transcend cultural lines, but are necessary for the survival of a culture (ie the culture would cease to exist in time if something like murder or lying were thought to be morally good). These would be the moral values. They could pass the others off as values of taste.
Premise 2 also seems to be very weak. Who says that differences of these sorts should cast doubt on objective morality? Just because people are behaving badly we ought not to think that they are actually behaving badly? That's ridiculous. Differences in moral behavior doesn't really seem to entail anything with regard to whether moral values are an ontological reality.
So, this argument not only doesn't seem to be sound, but also seems to be invalid, at least in the form given by my teacher. But he didn't really have much good to say about this one either.
Metaphysical argument from queerness
P1. If moral values were objective, then we would expect there to be moral properties out in the world.
P2. There are no moral properties out in the world (for such properties would be very queer and utterly unlike ordinary properties like heaviness, roundness, or numbers).
C. Therefore, moral values are not objective.
While I tend to agree with the first premise, there are objectivists who would classify objective morality in other ways, though I'm not entirely sure how that would work.
Premise two, I think, is really bad. First off, how does something being odd, strange, queer, weird, unlike something else, whatever you want to call it, entail its non existence? The quantum physical world is extremely strange. Does that mean we should doubt its existence?
Furthermore, Mackie is simply stacking the deck here by classifying things so that his argument goes through. Who says that moral properties are queer? Who says they are weirder and utterly unlike the other properties listed? Frankly, you can say that any property listed there is unlike the other. Roundness is not like heaviness in pretty profound ways. Likewise, numbers, as abstract objects, are also extremely strange in the minds of most philosophers. Unless one holds to some sort of reductionist materialism I don't see any reason to support the contention that one of these types of properties is queer to the point that we should start to question its existence.
Epistemological argument from queerness
P1. If there were moral properties in the world, then we would need a separate faculty from perception to detect them.
P2. We do not seem to have such a faculty.
P3. So, even if there are moral properties in the world, we can't know that.
C. Therefore, it is not reasonable to believe that moral values are objective.
I first off would begin by questioning the way premise one is worded. I assume when my prof. says "perception," being a product of latent positivism in the establishment philosophy departments, he means physical perception. What we perceive with our five senses. He needs to make that clear, since I would say there is moral forms or perception, similar to how there is a logical perception (perceiving the logical status of an argument for instance). But, if he means physical perception, then I would agree with premise one.
Premise two is ridiculous. I wonder if Mackie actually ever went outside his office. Moral perception is something that we encounter every day. You can't help but have a moral feeling/perception/sense about anything you hear about. You can simply sit there and think of a moral situation, say someone brutally beating a woman for trying to learn how to read, and immediately and irrepressibly you have a moral sense about that act. Somewhat like your physical senses, it forces itself upon you whether you like it or not. I think it's eminently clear that we have a faculty that picks up on the moral properties some act has. I think Mackie's materialism is undergirding this claim. Because our moral sense doesn't act on a strictly material level, it simply can't be true. But I think our moral sense is more obvious than our physical senses, because there doesn't have to be any sort of external stimuli to judge the moral status of an act, because you can imagine an act in a dark room and your moral sense will react to it. I have no more reason to question my moral sense than I do my physical senses.
Premise three relies on premise two.
My teacher seemed to think that both of the queerness arguments were pretty good here. But I don't think so at all. I honestly wonder where he's coming from, because these arguments, to me, rely on a vary large amount of unbacked assumptions and really are pretty poor. This makes me want to get into a philosophy department in a university or something even more, so I can give another perspective other than this latent assumed naturalism in university philosophy departments. If my Lord is willing, maybe I will!
Why anyone takes Mackie's subjectivism seriously is beyond me.