There are two kinds of relativism, moral and epistemic. The first kind of relativism says that there are no objective moral rules, but only what individuals or groups decide for themselves in certain times and places – like taste in foods or fashions. The second kind says that no propositional statements about reality are objectively true.

I found this list of the seven flaws of moral relativism at the Australian site Faith Interface.

Here’s the summary:

1. Moral relativists can’t accuse others of wrongdoing.
2. Relativists can’t complain about the problem of evil.
3. Relativists can’t place blame or accept praise.
4. Relativists can’t make charges of unfairness or injustice.
5. Relativists can’t improve their morality.
6. Relativists can’t hold meaningful moral discussions.
7. Relativists can’t promote the obligation of tolerance.

Here’s my favorite flaw of relativism (#6):

Relativists can’t hold meaningful moral discussions. What’s there to talk about? If morals are entirely relative and all views are equal, then no way of thinking is better than another. No moral position can be judged as adequate or deficient, unreasonable, acceptable, or even barbaric. If ethical disputes make sense only when morals are objective, then relativism can only be consistently lived out in silence. For this reason, it is rare to meet a rational and consistent relativist, as most are quick to impose their own moral rules like “It’s wrong to push your own morality on others”. This puts relativists in an untenable position – if they speak up about moral issues, they surrender their relativism; if they do not speak up, they surrender their humanity. If the notion of moral discourse makes sense intuitively, then moral relativism is false.

I sometimes get a lot of flack from atheists who complain that I don’t let them make any moral statements without asking them first to ground morality on their worldview. And that’s because on atheism morality IS NOT rationally grounded, so they can’t answer. In an accidental universe, you can only describe people’s personal preferences or social customs, that vary by time and place. It’s all arbitrary – like having discussions about what food is best or what clothing is best. The answer is always going to be “it depends”. It depends on the person who is speaking because it’s a subjective claim, not an objective claim. There is no objective way we ought to behave.

The whole point of atheism is to pursue pleasure without the bonds of morality – there is no other reason to do anything on atheism except for the pleasure it gives you. You do fashionable things to feel good getting praise from your neighbors, and you do unfashionable things in private to make yourself feel good and you hope that no one who is powerful enough to hold you accountable ever finds out. There’s no way you were made to be.