Prudential reasons and the prudential companions in guilt argument

According to the moral error theory, all moral judgements which attribute moral properties are untrue. According to the prudential error theory, all prudential judgements which attribute prudential properties are untrue. The prudential companions in guilt argument contends that, if arguments for the moral error theory succeed, then analogues of those arguments establish the prudential error theory, but the prudential error theory is false, so arguments for the moral error theory fail. In this paper I assess whether the most popular argument for the moral error theory, the argument from reasons, threatens to establish the prudential error theory. My key conclusion is that some but not all ways of developing the argument from reasons support the prudential error theory.