Mackie's response to my last post

Mackie, in his article "The Subjectivity of Values" brings five arguments in support of his thesis that values are subjective, and not objective (and that people's common sense views are in error in this regard). The first one he calls "The argument from relativity", and it is essentially the view that I tried to criticize in my last post. The argument goes like this: the best explanation of the variance in moral belief across cultures is not that there is some objective value that people have more or less epistemic access to. Rather, the best explanation of this observed phenomenon is that people's moral beliefs are based on their ways of life and cultures. That is, that they're subjective.

I argued that this is an unfair argument, because no one denies that ancient history is objective even though there is a wide variance. Why not say that the disagreement in ancient history shows that the subject matter itself is subjective?

Mackie briefly raises this point and tries to counter it. He writes,

"Disagreement on questions in history or biology or cosmology does not show that there are no objective issues in these fields for investigators to disagree about. But such scientific disagreement results from speculative inferences or explanatory hypotheses based on inadequate evidence, and it is hardly plausible to interpret moral disagreement in the same way. Disagreement about moral codes seems to reflect people's adherence to and participation in different ways of life. The causal connection seems to be mainly that way round: it is that people approve of monogamy because they participate in a monogamous way of life rather than that they participate in a monogamous way of life because they approve of monogamy."

It seems to me that this argument is fishy. He's comparing the measured opinions of historians versus the beliefs of the masses. That seems to me unfair. I think that if you look at the way trained ethicists go about thinking about ethical problems it's much closer to making "speculative inferences or explanatory hypotheses based on inadequate evidence" than just assuming whatever their culture does.

It may be that people in general believe things based on their culture. But the real historical or scientific parallel to what he's observing in science would be the widespread belief in the American myth that varies with the French or British founding myth. Indeed, among the public we find wide variance in their opinions about the past. The best explanation is that these people aren't accessing some objective past, but rather are just believing what they are because of culture and background. But that's not the point! People aren't the ones that we should expect to be looking carefully at the evidence! There might very well be something objective about the past, but most people don't look for evidence about the past. Historians do. And ethicists might do so as well, even if there is widespread disagreement about what is good or right.