…The traditional classification of fallacies of reasoning describes many of them as involving an ‘argument to…’ They include: A. ad ignorantiam: arguing that a proposition is true because it has not been shown to be false, or vice versa. A. ad baculum (literally, arguing to a cudgel): supporting a conclusion by highlighting the dire consequences of not believing it (supposedly a fallacy, but pragmatism insists that similar considerations underlie all processes of belief formation). A. ad hominem: attempting to disprove what a person holds by attacking the person (less commonly, supporting a person’s contention by praising the person), or, more generally, arguing in a way that may or may not be forceful against a particular person’s position, but does not advance matters for those who do not hold that person’s particular combination of beliefs. It should be noticed that in some contexts, such as deciding whether to accept a person’s testimony, ad hominem description of the person, for instance that they are notorious liars, may well be relevant. A. ad misericordiam (to pity): an argument trading on the sympathies of people. A. ad populum: an argument appealing to the prejudices of the people. A. ad verecundiam: appealing to an authority outside its legitimate area; illicitly trading on reverence and respect, as in celebrity endorsements.

Although processes of argument fall into these and other errors, it is difficult to separate improper from proper uses of arguments that might be described in these ways. For instance, appeal to sympathy, or popular belief, or authority might in some circumstances be quite legitimate. Except for argumentum ad hominem, the terms are not commonly used.