[link|http://www.solstice.us/russell/science-ethics.html|Russell] had a few things to say about this:
Ethics, if the above analysis is correct, contains no statements, whether true or false, but consists of desires of a certain general kind, namely such as are concerned with the desires of mankind in general - and of gods, angels, and devils, if they exist. Science can discuss the causes of desires, and the means for realizing them, but it cannot contain any genuinely ethical sentences, because it is concerned with what is true or false.
The theory which I have been advocating is a form of the doctrine which is called the "subjectivity" of values. This doctrine consists in maintaining that that, if two men differ about values, there is not a disagreement as to any kind of truth, but a difference of taste. If one man says "oysters are good" and another says "I think they are bad," we recognize that there is nothing to argue about. The theory in question holds that all differences as to values are of this sort, although we do not naturally think them so when we are dealing with matters that seem to us more exalted than oysters. The chief ground for adopting this view is the complete impossibility of finding any arguments to prove that this or that has intrinsic value. If we all agreed, we might hold that we know values by intuition. We cannot prove, to a colour-blind man, that grass is green and not red. But there are various ways of proving to him that he lacks a power of discrimination which most men possess, whereas in the case of values there are no such ways, and disagreements are much more frequent than in the case of colours. Since no way can be even imagined for deciding a difference as to values, the conclusion is forced upon us that the difference is one of tastes, not one as to any objective truth.
YMMV.
Cheers,
Scott.