Gee I'm verbose. Here's another comment that was too large to fit on Eric Reitan's blog post, following on from my previous one.
Thanks for clarifying your position.
"[I claim] that belief in objective moral truths is not a precondition for individual moral motivation, nor is a precondition for what he and I would both judge to be social progress"
We can agree there too. I still have a little trouble understanding how you can attribute weight to an idea such as "social progress" if you believe it to be an entirely subjective phenomenon. As I said, I believe you may have more of a belief in objective morality (ie. one that gravitates towards the empathy that is hard-wired into us all) than you care to accept. But this is perhaps a merely academic or semantic quibble.
"In essence, I argue against the claim that moral relativism necessarily collapses into 'anything goes'"
Our viewpoints probably diverge here. While I don't think that adopting moral relativism will open the floodgates of chaos, I can think of myriad examples where moral relativism has to some extent caused severe injustice.
For example, The savage persecution of Christians and political insurgents in Ancient Rome seems to me to be firmly based in moral relativism. That is, the morality system that permitted Romans to crucify people or tear them to shreds in the circus was one that was clearly rooted in the self interest of Ceasar and/or Rome, rather than a morality system that attempts to be more objective (eg. rooted itself in an abstract philosophical idea, an ethos reached by global consensus, or the commandments of a supra-human deity). Ditto with slavery, the Holocaust, or the Crusades.
In more recent times, USA, a nation with a supposedly Christian (ie. supposedly morally objectivist) majority, chose the moral relativist route when they decided that crimes they would never have accepted against Americans were permissable when committed against Japanese, Koreans, Chileans, Nicaraguans, Vietnamese, Cubans, or Iraqis. Personally, I think the world would be a better place if the US took a slightly more objectivist stance on morality rather than one that was firmly rooted in unrepentant subjectivity.
Still, you can of course name myriad examples where a belief in objective morality has led to numerous atrocities, including some of the instances I myself cited. So this issue is unlikely to ever proceed beyond a stalemate.
However, I believe that any discussion about this is ultimately hypothetical, because I have never seen evidence that pure moral relativists actually exist. We might conceptually subscribe to such an idea, but I've yet to meet someone who actually lived their life in a thoroughly morally relativistic manner.
Before I back that claim up, consider for a moment two other moral ideas: individualism and collectivism. You've no doubt met many individualistic people in your life. But have you ever met someone who was 100% individualistic - who has NEVER put someone else's wellbeing over her own? I doubt it. Similarly, have you ever met someone who is truly collectivist - who believes in equality to such a level that she has never put her own desires ahead of anyone elses? Even more doubtful.
Ideas like individualism and collectivism, like many such ideas, are simplistic distortions of a muddier reality. In real life, all of us are partially self-motivated and partially motivated by the needs of others...regardless of what philosophy or politics we might claim to ascribe to.
I would argue that moral relativism and moral objectivism are similarly things which don't exist anywhere other than in the realm of theory. In reality, there is a broad spectrum between the two, and people can be found almost anywhere on that spectrum. Personally, I have never met a single person who could genuinely be found on either of the extremes. Every 'objectivist' will colour her own morality with subjective ideas and biases, or those of her community or era. And every 'relativist' will inherit much of her morality from sources larger than herself that she (willingly or inadvertantly) shares with others across space and time - not least from her hardwired empathy.
That's why there's such an incredible amount of overlap between people's moral views. It's safe to assume that you and I, for example, both believe that murders should be punished in some way, that child molesters are committing a wrongdoing, and that people don't have the right to take away from us something we have bought or created.
Even those with seemingly radical differences are often not that different. Both rabid pro-choice people and rabid pro-life people believe that murdering a baby is dead wrong...they simply disagree on what a baby is. Anti-war activists and fervent war supporters are often motivated by the same sense of justice....they just differ in who they perceive the victim to be and what the prescribed remedy should be.
I believe it's inaccurate and misleading to think of morality as something that can be simplified down to a binary 0 or 1, with relativism being one and objectivism being the other.
So, in a sense, I agree with you that moral relativism does not collapse into "anything goes". Though I'd argue that this is because, first and foremost, moral relativism doesn't actually exist anywhere other than in the conceptual sphere.
Though we all look different, with different shapes, sizes, features and skin colours, the overall pull of our DNA cannot be escaped by anyone. That human DNA expresses itself in every one of us differently, yet always in a human way. As with physical appearance, so with morality. Our moralities are all unique, subjective and evolving....yet they still all spring from the same blueprint, whatever that blueprint may be.