 Now that we have set aside the question of how to formulate the error theory, we can deal with the most important recent argument for the theory: Mackie’s Argument from Queerness. We won’t attempt a full scholarly treatment of Mackie’s argument here (though see Joyce &amp; Kirchin 2010, as well as §3.2 of the entry on  moral anti-realism);  we are more interested in the broad concerns about normativity it spawned. The general thought here is that normative facts, if they existed, would be really weird. This is a thought many have shared, perhaps inchoately. As we’ll see, it is difficult to determine how exactly to flesh out the thought. (In what follows, we’ll follow the precedent set by Mackie and use the term “queer” for “weird”.)