Relativism vs. Subjectivism

Concerning ethics, I think that there are lot of people who have a knee-jerk reaction to relativism. As far as I can tell, this is because they think that this reduces morality to something subjective, and hence something arbitrary. But this need not be the cause, and perhaps is actually something incompatible with relativism. For an analogy, let us take the case of space-time relativism in physics. This does not mean that there is no space or time; on the contrary, Einstein thought that by showing the relativity of space and time to individual perspectives, he had proven their objectivity. If they truly were subjective, then a single individual perspective should account for them (such as Euclidean mathematics in Kant's system). But the fact that space and time can only be viewed within given perspectives, and yet these perspectives hang together, show that space and time are something real outside of any one given perspective.

Similarly, why is there a problem in saying that moral claims are relative to a given perspective? This is not to say that they are merely individual, but rather that we can only know claims from a given standpoint. Or, to put it another way, we can only be virtuous within our given contexts. For an example, the virtue of generosity requires some sort of wealth to give away. It only makes sense within a certain context of having something to give away. Other contexts demand different virtues. If you don't have any wealth, you can't engage in the same activities as those who are independently wealthy. So in the same way the practices involved in living in a Chinese society may differ from those involved in living in an American society, based on what is available, how things will affect the persons around oneself, etc. It is not clear that there need be general moral rules guiding these practices for them all to be the best ethical practices, other than some basic sense of "the good". (Edit: where "the good" would seem to entail some knowledge of the natures of whatever we are talking about; the good for human beings is what lets human beings be most human, and so on. This may be relative to whatever is talked about, or there may be some general sense of goodness/aesthetic sense applicable to different cases with practice and insight.)

Further, it is not clear that there need to be extrinsic moral principles to say that some systems of ethical behavior are inferior. The Nazi regime doesn't seem to be self-sustaining. What happens when all of the current "others" are sent off to concentration camps? Either a fundamental shift in ethics must take place (which should have existed in the first place), or there will be a need for a new superior race and hence inferior differences. The cycle must continue, and there cannot be a stable society. So the system falls apart internally. Now, psychology and sociology may be able to supply a better story for why this would happen than the naive one I present here, but the point remains the same. A society that exists by setting itself from others cannot exist apart from some sort of others.

If all of this is correct, then relativism is a form of moral realism; in fact, it may be a better form than moral absolutism. Why? Because absolutism (saying that there are these specific moral absolutes) still feels the need to posit the absolutes; there would not be morality unless we take an active stance in making morality exist. Relativism lets things be what they are, and trusts (hopefully rationally and empirically) that morality will really arise from the natures of things. And if it cannot arise from the natures of things, in what sense could it possibly be objective?