Atheism and morality

[Inigo]

No, the reverse is true. My belief that Xing is wrong contradicts your belief that Xing is right if and only if we are talking about the same morality. So, my belief that Xing is wrong is the belief that morality instructs us not to X. Your belief that Xing is right is the belief that morality instructs us to X. These beliefs contradict. But they are beliefs about one morality.
If my belief was that morality1 instructs us not to X, and your belief was that morality2 instructs us to X then our beliefs do not contradict.

Xing in your example is confusing. Can we use a real example?

Abortion. Essentially 2 sides of the argument. The first is that the rights of the unborn child trump everything else. the second that the woman's right to choose trumps all.

If that is a dispute over the same moral issue then the role of your God is merely to flag up that abortion is a moral issue and then the individual comes down on one side or the other.

Doesn't seem like much of a role - seems far more like a decision to be made by an intelligence, us, independently. That decision would be made on the basis of upbringing probably more than anything else.

No, it is better to use 'Xing' as if one mentions a real case someone will dispute the normative issue of the rightness/wrongness of abortion rather than focussing on what the fact of disagreement tells us about our concept of morality.

I am entirely unclear how you arrive at the view that the role of the god is just to highlight that it is a moral issue. This is clearly not what my view is. A god's instructions determine the rightness or wrongness of a deed as wrongness in an action just consists in the fact it is an act a god instructs us not to perform. Moral disagreement is simply disagreement about what, exactly, morality instructs us to do.