Not infrequently one comes across the expression, "That's an ad hominem," in various dialogue contexts, implying one has obviously violated a rule of reasoning or standard of good argument. And, in fact, that may often indeed be the case, the particular fallacy in this instance being an argument (or a move in an argument) "directed to the man," in other words, one has criticized the arguer at the expense of the argument. In Douglas Walton's words, an argumentum ad hominem "is a personal attack on an arguer that brings the individual's personal circumstances, trustworthiness or character into question." In our assessment of the plausibility, soundness or persuasiveness of an argument, such a "personal attack is inherently dangerous and [unduly] emotional...and is rightly associated with fallacies and deceptive tactics of argumentation." What follows is generally inspired by Walton's work, especially his book, Informal Logic: A Handbook for Critical Argumentation (1989).
Walton informs us that there are generally three types of ad hominem argument:
1. The "abusive" ad hominem "is the direct attack on a person in argument, including the questioning or villification of his character, motives, or trustworthiness."
2. The "circumstantial" ad hominem "is the questioning or criticizing the personal circumstances of an arguer, allegedly revealed, for example, in his actions, affiliations, or previous commitments, by citing an alleged inconsistency between his arguments and the circumstances."
3. The "poisoning the well" type of ad hominem "is said to occur when the critic questions the sincerity or objectivity of an arguer by suggesting that the arguer has something to gain by supporting the argument he has advocated."
It's important to appreciate, however, that the ad hominem argument is just that, namely, an argument, and thus "is not always logically unreasonable or fallacious." The foremost reason for this can be inferred from the fact that the argumentum ad hominem, when fallacious, is by definition an informal (thus not formal) fallacy, hence the determination of whether or not the argument is reasonable entails a close examination of its specific incarnation within a particular dialogue form and context. Put differently, in the myriad rhetorical fora of practical reasoning and dialogue forms in everyday social and institutional settings, the identification of an informal fallacy is neither "field invariant" (Toulmin 2003) nor transparent. We therefore need to carefully consider precisely how this argument form is being used in a dialogue context before we can claim the argument is fallacious or unreasonalble. On occasion, what appears at first glance to be a fallacious ad hominem may in fact turn out to be a rather reasonable or perfectly appropriate--thus nonfallacious--use of the ad hominen argumentum. Walton provides us with a fairly straightforward if not simple illustration of a nonfallacious use of the ad hominem:
GEORGE: The notorious problems we have been having with postal strikes means that there is no longer reliable mail service provided by the government. I think we ought to allow private, for-profit mail delivery companies to compete on an equal footing with the Post Office.
BOB: But George, you are a communist.
Let us suppose that in this case George is an avowed communist and has based his previous arguments on many standard communist principles and positions. Now in many cases, calling your opponent in an argument a communist could be a fallacious type of ad hominem attack. However, in this instance, Bob seems to have a reasonable point. If George is an avowed communist, and communists are for state control and against private enterprise, then how can George consistently argue for a for-profit mail service run by private enterprise. It seems like a legitimate question. Of course, George may be able to resolve the ostensible inconsistency in subsequent dialogue. But surely Bob is justified in challenging the consistency of George's position at this point in the dialogue. If so, then in this case, Bob's circumstantial argument is not fallacious.
In a courtroom, the testimony of a witness may be undermined by subjecting it to questions that center upon her motives or character or past behavior in an effort to expose the individual's testimony as irredeemably tainted, as considerably less than impartial, trustworthy, or true. In such cases, it appears that the ad hominem is well-suited to the task at hand and thus is a perfectly appropriate argument. This is not to suggest, of course, that it is invariably reasonable in such settings or not structurally prone to abuse.
Sometimes it's quite difficult to unequivocally determine whether or not an ad hominem is fallacious, as it's not clear precisely how much contextual information is essential to a fair assessment of the argument. The following, for example, enables us to see how interpretive issues having to do with the particular dialogue and its interlocutors may be decisive in a complete reckoning of the relative merits of the argument on each side:
PARENT: There is strong evidence of a link between smoking and obstructive lung disease. Smoking is also associated with many other serious disorders. Smoking is unhealthy. So you should not smoke.
CHILD: But you smoke yourself. So much for your argument against smoking.
If we've had any philosophical training, and perhaps even if not, I suspect we're tempted to be dismissive of (if otherwise sympathetic to) the child's response to the parent's seemingly impeccable argument. And yet should not something be said on behalf of the child's retort challenging the parent's patent personal inconsistency between word and deed? Assuming the parent intends the argument to be pedagogically persuasive, that is, to steer the child away from the putative charms of smoking, then the argument is not at all as strong as it first appears (I know: a sound argument need not be persuasive, but I'm concerned with arguments in the real world, in which case we want the argument to be both sound and persuasive). In some worlds, we find the child appreciating the force of the argument irrespective of the parent's personal inconsistency, but outside those worlds, that is an unrealistic expectation. Or, as Walton concludes, "surely it is not unreasonable to require that the parent owes the child a defense or examination of his position."
The argumentum ad hominem is often grouped with other so-called emotional fallacies, including "argument to the people" (argumentum ad populum), "argument to pity" (argumentum ad misericordiam), and "argument to the stick" (argumentum ad baculum). These in turn, are classified as informal fallacies as such, of which there are over forty in number (Angeles 1992: 104-110). Referring to these argument forms as "fallacies" even if only informal, is misleading owing to the fact that, qua argument forms, they are not even prima facie fallacious! Nevertheless, it is probably prudent to be presumptively suspicious when we encounter these argument forms, given the frequency with which many of them are used inappropriately. But because we're in the realm of informal logic, the determination of whether or not these forms are in fact fallacious requires careful examination of their use in specific dialogue types and contexts, including the specific chains of reasoning. We might also bear in mind that practical reasoning in everyday social settings is often at best primarily presumptive, where a presumption is a speech act betwixt and between an assumption and an assertion. While we can identify both deductive and inductive reasoning in presumptive argument chains, it is important that our standards and criteria of argument plausibility and persuasiveness are sensitive to this overarching presumptive character, which entails ever-shifting burdens of proof and presumptions alternatively required, reasonable, or permissible.
Strictly speaking, then, if the argument forms classified in logic textbooks as "informal fallacies" are not even prima facie fallacious, they are innocent until proven guilty. Take, for instance, the "argument to the stick," a descriptive label that screams unreasonable or irrational, an argument form that is, finally, prima facie fallacious. Yet even here this form may be, and often is, perfectly proper: as in negotiation dialogues that occur in judicial plea-bargaining, international legal and political settings involving nation-states, and collective bargaining between labor and management. I'm assuming here that while we may conceptually distinguish between "arguing and bargaining" (Elster 1991), on the ground these are inextricably intertwined, making this a perfectly, if painfully, acceptable form of argument. That we require a close examination of these so-called informal fallacies in their dialogues types and social settings to ascertain whether or not they are truly fallacious is perhaps most readily seen in the case of the "argument from authority" or "appeal to expertise" (argumentum ad verecundiam).
In sum, the argument forms referred to as "informal fallacies" are capable of being more or less strong or weak, reasonable or unreasonable, fallacious or not, persuasive or not.
References and Further Reading:
- Angeles, Peter A. The Harper Collins Dictionary of Philosophy. New York: HarperCollins, 2nd ed., 1992.
- Bailin, Sharon W. and Harvey Siegel. "Critical Thinking," in Nigel Blake, et al., eds. The Blackwell Guide to the Philosophy of Education. Malden, MA: Blackwell., 2003: 181-193.
- Elster, Jon. "Arguing and Bargaining in the Federal Convention and the Assemblée Constituante," (1991) Working Paper No. 4, Center for the Study of Constitutionalism in Europe. Available: http://www.geocities.com/hmelberg/elster/AR91AAB.HTM
- Fisher, Alec. The Logic of Real Arguments. Cambridge, UK: Cambridge University Press, 1988.
- Groarke, Leo. "Informal Logic," The Stanford Encyclopedia of Philosophy (Fall 2008 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/fall2008/entries/logic-informal/.
- Toulmin, Stephen. The Uses of Argument. Cambridge, UK: Cambridge University Press, 2003 ed.
- Toulmin, Stephen, Richard Rieke and Allan Janik. An Introduction to Reasoning. New York: Macmillan, 1984 ed.
- Walton, Douglas N. Informal Logic. Cambridge, UK: Cambridge University Press, 1989.
- Walton, Douglas N. Plausible Argument in Everyday Conversation. Albany, NY: State University of New York Press, 1992.
- Walton, Douglas N. Arguments from Ignorance. University Park, PA: Pennsylvania State University Press, 1996.
- Walton, Douglas N. Appeal to Expert Opinion: Arguments from Authority. University Park, PA: Pennsylvania State University Press, 1997.
- Warburton, Nigel. Thinking from A to Z. New York: Routledge, 2nd ed., 2000.