An expressed argument doesn’t have a bias, the person making it has a bias. The argument can be refuted on its merits. Arguing that we should discount an argume

An expressed argument doesn’t have a bias, the person making it has a bias. The argument can be refuted on its merits. Arguing that we should discount an argument because of its speaker’s bias is the flip side of arguing that we should give it more weight because of the speaker’s authority, another fallacy. That being said, if the speaker (or anyone else) attempts to argue from authority, I feel it’s appropriate to use a circumstantial ad hominem argument. Not to discount the argument itself, but to point out that their own appeal to authority is not only fallacious, but also unfounded.