There are certain kinds of arguments which do not deserve to be taken seriously. I take this claim to be uncontroversial. For example, Aristotle mentions that arguments against the principle of non-contradiction inevitably fail because each such argument cannot prove its claim without implictly relying on the PNC. Several moral arguments fall into this class as well. Arguments in favor of racism or the killing of innocents are paradigmatic examples: anyone who still believes that ‘race’ is anything but a social construction just is ignorant, and he who argues for the killing of the innocent is a monster.
But even if some arguments can be dismissed a priori, it is important to provide an account for why these claims do not merit serious discussion. While the examples that I provided above are uncontroversial, the rejection of such claims needs to be carefully distinguished from polemic. Polemics often group serious arguments into the category of arguments not to be taken seriously. For example, the new atheists do not even consider theistic arguments to be taken seriously, and so they spend all their days ridiculing theists and engaging in self-congratulatory behavior. Although I am unequal to the task of enumerating a complete list of criteria to distinguish serious arguments from arguments not to be taken seriously, I have two suggestions.
First, no philosophical movement which was pursued by a large number of philosophers over long periods of time deserves to be dismissed. This does not mean that all arguments to be taken seriously must have come from one of these movements. Rather it expresses the intuition that with that tradition of philosophy were at least some good philosophers who were capable of careful thinking. As a matter of fact, most philosophical movements were started by such brilliant thinkers. Anyone who has spent any time reading St. Thomas, David Hume, or Bertrand Russell can see that each was brilliant; and because they were brilliant, they developed a following among other careful thinkers.
Second–and probably more controversially–an argument deserves consideration only if it conforms to some sort of natural law. I don’t mean that everyone must subscribe to a natural law ethic. What I am claiming is that there are a set of basic moral principles that have been acknowledged in every time and culture, even if these principles have been applied differently from culture to culture. The killing of innocents, respect for the dead, and respect for the property of others all fall into this category.
I’m not quite satisfied with my formulation of my second point. Although I think the general idea is correct, I still think it leaves something to be desired.