I just want to try to again clarify the issue I wish to raise with the questions I asked in the OP:
With which meta-ethical theses is materialism logically consistent? I certainly don't see how it is possible to argue that materialism can accommodate any form of moral realism, which entails the reality of objective moral facts--e.g., facts such as denoted by propositions such as “rape is immoral” or “it is good to avoid causing unnecessary suffering”. It's quite odd to see people here suggesting that materialism is compatible with the existence of objective moral facts, and, moreover, that the thesis of materialism does not preclude the ability of persons to choose to engage in moral behavior. In the short while I've been a member of RF, I've often found that the very mention of the phrase “objective moral facts” seems to offend many people, and there is great resistance to the suggestion that people can choose what acts they will engage in.
I can only conclude that logical consistency relegates the materialist to endorsing some form of moral anti-realism as his/her meta-ethical thesis--moral nihilism or relativism--odious and inadequate though these are. In the OP of a thread I posted a while ago, I noted some of the hopefully discomforting ramifications of moral anti-realism:
The Social and Political Regressiveness of Moral Anti-realism
Was there anything immoral in white Americans (and colonists before them) importing and subjugating Africans as their slaves? The moral nihilist would deny any immorality in it, and the relativist would have to say that there was nothing ultimately or objectively wrong with it--many white Americans in non-slave states and about 100% of slaves considered slavery abhorrent and inhumane, but, since Americans in Confederate states were willing to try to secede and fight a bloody war in order to maintain the institution of slavery, it was not immoral there, according to the relativist.
Was there anything wrong with Jim Crow laws and other legalized inequalities inflicted upon African Americans after the Civil War? Again, the moral anti-realists can only assert that there was nothing (ultimately or objectively) immoral with such denigration and lawful discriminatory treatment of African Americans.
What was wrong with the ancient doctrine of coverture (in which a woman was deprived of any legal status beyond that of her husband), the denial of suffrage for women, or the non-recognition that a man could rape his wife? Nothing, according to the nihilist; and nothing in those societies that approved of such injustices toward women, according to the relativist. Even today there are countries where women are deprived of the legal status and rights that men enjoy.
In this century in the US, after the Goodridge decisions by the Massachusetts Supreme Judicial Court in 2003/2004, there were eventually 30-something states that amended their constitutions in order to deny same-sex couples and their children the important rights and benefits that come with the couple's ability to participate in civil marriage. Some of these amendments passed by huge majorities of voters. Did any moral anti-realist speak out against these provisions, express any umbrage about the injustice to same-sex couples and their children? Apparently not, unless they were being inconsistent with their nihilism or relativism.
By not recognizing any wrongs or injustices beyond legal wrongs, moral anti-realists are and will always be social/political regressives, unprogressives. illiberals who lack any impetus for change. Social and political wrongs can never be righted by those who are blind to moral wrongs, that is, blind to wrongs beyond legal wrongs.
This is not to claim that there are no self-avowed materialists who choose to be vegans or who choose to engage in otherwise moral acts and behaviors. But that claim--the choosing to engage in moral behaviors--alludes to and is premised on two propositions that materialism account for or accommodate: the proposition that there are moral behaviors (that there is an actual, objective difference between moral and immoral acts), and the proposition that a person can choose the acts s/her performs. As far as I can tell, no one here has argued that the thesis of materialism is able to account for or accommodate those two propositions. Am I right or wrong? If I am wrong, then please cite the evidence by which one can conclude that materialism can account for or accommodate those two propositions.
Also, nothing I have said here is to imply that materialism is the only metaphysical thesis that is unable to account for or accommodate those two propositions.
