Are moral properties impossible?

Perhaps the actual world does not contain moral properties. But might moral properties be impossible because no world, possible or actual, contains them? Two metaethical theories can be argued to entail just that conclusion; viz., emotivism and error theory. This paper works towards the strongest formulation of the emotivist argument for the impossibility of moral properties, but ultimately rejects it. It then uses the reason why the emotivist argument fails to argue that error-theoretic arguments for the impossibility of moral properties face the same conclusion. Finally the paper argues that these arguments for the possibility of moral properties might have consequences for our thinking about their actuality, regardless of whether we accept emotivism or error theory.