There is a powerful argument that is frequently used in metaethics (and elsewhere). It’s based on the idea that disagreement requires shared concepts. Thus, by looking at who we can intuitively disagree with we can determine who we share our concepts with. And, in when it comes to morality, it seems we can disagree with people who classify very different things under moral terms. As a result, it is argued, ethical terms cannot have ‘descriptive content’. I used to think that this great argument works. Today I’m feeling less certain about this and I’d like to hear about your thoughts. Here is why.