Where to diamonds get their value?
First off, I agree that economic value is a good analogy for framing a discussion of moral value.
Second, I think you haven't thought this analogy through enough. If you had, you wouldn't be a cultural
relativist. You would either be an personal
relativist or a faint-hearted absolutist, depending on the details of your analogy.
To explain why, let me start by answering your question. In the language of economics, diamonds have use value
for various reasons: their beauty makes some people happy looking at them, their sharpness helps other people cut things, and so forth. Diamonds also have labor value
: digging them out of the ground costs people effort. Finally, diamonds have exchange value
, also known as prices
: people can exchange them for other things they want. Hence, diamonds get their value in several ways because "value" is a multi-faceted term in economics.
Two observations about these facets: First, it doesn't take a society to determine use value or labor value. All it takes is one person, acting rationally on his or her senses. Robinson Crusoe, alone on his island, could tell you exactly whether the beauty of a one-carat diamond is worth to him the labor of mining one. To be sure, if you polled a hundred different Robinsons on a hundred different islands, you might get a different answer from each. That would depend on the geology of each island, as well as the tastes and skills of each Robinson. But none of the Robinsons would need a society to answer your question. In other words, use value and labor value don't vary from society to society; they vary independently from person to person. That's the first observation.
The second observation is that the exchange value
of diamonds, which does
presume a society in which people exchange diamonds, is not
an independent variable. At market auction, diamond prices adjust to be both high enough that the lowest-bidding producer finds them worth producing, as well as low enough that the highest-bidding consumer finds them worth using. Since every diamond sold is a diamond bought and vice versa
, the diamond market will settle at one
price. It will be more or less the same worldwide. It will also be more or less stable over time.
So now that we've thought the economic side of your analogy through, where does that leave the moral side? It depends on what's analogous to what. If moral value corresponds to economic use value or labor value, there is no reason to stop at cultural relativism. You should be an personal
relativist because values vary from one person to another. On the other hand, if moral value corresponds to prices, to economic exchange value, you should be a faint-hearted absolutist. You should be an absolutist because the price of commodities like diamonds is pretty stable across time and space. And you should be faint-hearted to the extent that prices do fluctuate. Either way, cultural
relativism makes no sense under your analogy.