  On the first answer, the parity undermines the skeptical or antirealist arguments because there are independent reasons for rejecting the conclusions they yield when applied to the other areas (it is assumed here that those reasons do not in turn undermine the parity claim). This would arguably cast doubts on the arguments. For if they yield incorrect conclusions in those contexts, why think that they do a better job in the case of ethics? In other words, the idea is that the parity provides resources for a reductio ad absurdum of sorts of the arguments.