The ad hominem fallacy is a sin

An argumentum ad hominem (or “argument to the man”) is the fallacy committed when, instead of addressing the merits of an argument someone presents you with, you attack the person himself – his motives, some purported character defect, or the like.  This disreputable tactic has, of course, always been common in public controversies, but resort to the fallacy seems these days nearly to have eclipsed rational public discourse.  A large segment of the country has made it a matter of policy never to engage its political opponents at the level of reason, but only ever to demonize them and shout them down.  Even in the Church, recent years have seen the ad hominem routinely deployed against even the most respectful and scholarly critics of Pope Francis’s doctrinally problematic statements concerning divorce and remarriage, capital punishment, and other matters.

 

This is not a mere foible in those prone to it, or merely a regrettable aesthetic defect in a polity.  It is sinful, sometimes gravely so.

 What the ad hominem fallacy is (and is not)

 

To see why, it is important first to understand what an ad hominem fallacy is – and what it is not.  As all logicians know, and as I explained at length in a post several years ago, merely calling someone a name, or calling attention to his character defects, is not an ad hominem fallacy and it is not necessarily morally objectionable.  Sometimes a person merits a nasty description, and sometimes what is at issue is precisely his moral character.  There is no ad hominem fallacy in judging someone to be dishonest, or feckless, or incompetent, or simply a scumbag, and then going on to say so.  Those may just be the facts, and there is nothing necessarily wrong with calling attention to such facts.

An ad hominem fallacy is committed when what is at issue is not a person or his character, but rather the truth or falsity of something he said or the cogency of some argument he gave, and instead of addressing that, you attack him or his character.  If I call Charles Manson a murderous, sadistic, and lying scumbag, I have not committed an ad hominem fallacy, but simply stated the facts.  If Charles Manson gives me an argument purporting to show (for example) that Amoris Laetitia is hard to reconcile with Christ’s teaching on marriage or that immigration laws need to be enforced, and in response to that argument all I do is call him a murderous, sadistic,  and lying scumbag, then I have committed an ad hominem fallacy.  

The ad hominem fallacy can take different forms.  The best known is the abusive ad hominem, which involves simply flinging invective at someone rather than addressing the merits of his claim or argument.  Again, it is not the invective per se that is fallacious.  Invective may or may not be appropriate, and even when it is wrong, the reason, sometimes, is not that it involves an ad hominem fallacy but rather a lack of charity, or discretion, or whatever.  What is fallacious is substituting invective when rational analysis and argumentation are what is called for.  Hence, if someone tries to give you an argument for some claim and in response you merely label him with an epithet like “bigot,” “fascist,” “Nazi,” “racist,” “homophobe,” “sexist,” “commie,” “cuck,” “neocon,” etc. and pretend that the alleged appropriateness of the label suffices to show that his argument can be dismissed, you are guilty of a textbook example of the abusive ad hominem.  

Sometimes people who are aware of the nature of the fallacy try to rationalize committing it by looking for legalistic loopholes.  Academic philosophers and other intellectuals sometimes do this when engaging opponents in non-academic contexts, such as Facebook exchanges, combox discussions, blog posts, etc.  Suppose I routinely demonize a certain opponent or group of opponents without ever addressing the substance of their arguments, and you accuse me of committing an ad hominem fallacy.  Suppose I respond by saying: “But I wasn’t even trying to address the arguments, so I’m not guilty of the fallacy.  I’m just expressing my low opinion of these people.”  The problem with this is that even if I am not explicitly claiming to address the arguments, my behavior does have an implicature to the effect that the arguments are somehow bad.  I am “sending the message” that the arguments of the people I am demonizing should not be listened to, even though all I’ve really done is thrown abuse at them rather than explaining what is wrong with those arguments.  So I am still guilty of an ad hominem fallacy, even if I have not committed it in a blatant way by explicitly saying something of the form: “You are a [bigot, Nazi, commie, etc.], therefore your argument is no good.”

Another form the ad hominem can take is the tu quoque fallacy, which involves rejecting someone’s claim or argument merely because he does not himself behave in a way that is consistent with it.  An enormous amount of online “debate” amounts to nothing more than this endless, dreary flinging back and forth of accusations of hypocrisy.  Now, accusing someone of hypocrisy is not in itself fallacious.  What is fallacious, again, is the pretense that such an accusation suffices to refute a claim or argument that the person has given.  If you assert that p is true and in response I point out that you nevertheless behave in a way that seems to imply not-p, that does not by itself show that you are wrong.  It may be that p really is true, and that the problem is not that you believe that p, but rather that you don’t practice what you preach.  Or it may be that there is another way to interpret your behavior so that it is compatible with your belief that p, and that you are not in fact guilty of inconsistency.  I would have to provide arguments to rule these alternatives out before I could claim to have refuted you.  Merely flinging an accusation of hypocrisy does not cut it.

A third form the ad hominem can take, and one that is also depressingly common in online discussion, is the poisoning the well fallacy.  This is committed when, instead of addressing the merits of an opponent’s claim or argument, you question his motivation for giving it.  The reason this is a fallacy is that the truth or falsity of a claim and the cogency of an argument by themselves have nothing whatsoever to do with the motives of the person giving it.  A person whose motives are bad can nevertheless give a good argument, and a person whose motives are good can nevertheless give a bad argument.  

Here too it is important properly to understand the nature of the fallacy.  Calling attention to someone’s motives is not by itself fallacious.  Sometimes we should consider someone’s motives.  For example, if our only reason for believing that Smith committed a certain crime is that Jones said so, and we know that Jones has long had a vendetta against Smith, then we have good reason to doubt Jones’s testimony.  What is at issue in this case is precisely Jones’s veracity, so that consideration of his motives is appropriate.  A fallacy of poisoning the well is committed when what is at issue is not a person’s veracity or some other aspect of his character, but rather the truth or falsity of some claim he makes or the cogency of some argument he gives, and instead of addressing that, we change the subject by accusing him of having bad motives.

A version of the poisoning the well fallacy that is extremely common today is the tactic of dismissing the arguments of an opponent on the grounds that they are allegedly motivated by “hatred.”  You think Amoris Laetitia is problematic?  You must be motivated by hatred of Pope Francis!  You disapprove of homosexual behavior?  You must be motivated by hatred of homosexuals!  You favor border enforcement?  You must be motivated by hatred of immigrants!  And so on.  Part of the problem here, of course, is that hatred is not necessarily the motive in any of these cases.  But the reason that poisoning the well is fallacious is that, even if hatred were a person’s motivation, that would be completely irrelevant to whether his claims are true and his arguments cogent.  Logically speaking, motives don’t matter.

Why the fallacy is sinful

One reason the ad hominem is morally problematic is that it is a sin against truth.  It may turn out that an opponent is right, so that if you dismiss what he says on ad hominem grounds, you will be blinding yourself, and others too (to the extent that they are influenced by your ad hominem attacks), to truths that might otherwise have been seen.  When the tendency to resort to the ad hominem fallacy becomes habitual, the probability that the one committing it will fall into error is, naturally, significantly increased.  

Consider too that ad hominem fallacies are often committed when one is angry at an opponent.  Therefore, someone who exhibits the vice of wrath – a habitual tendency toward anger that is disordered either in its intensity or its object – is bound to fall into the ad hominem fallacy quite often, and therefore bound to fall into error quite often.  In short, a person who is constantly angry and constantly vituperative with opponents is likely to be frequently wrong, though for that very reason he is also unlikely to see that he is frequently wrong.  Spiritually and cognitively, this is a very dangerous condition to be in.

A second reason the ad hominem is morally problematic is that it can involve sinful presumption.  No human being can have infallible knowledge of another person’s motives or spiritual state.  Of course, we can often form plausible opinions about such things.  Again, there is nothing wrong with judging that Charles Manson was an evil person, because his behavior quite clearly and consistently pointed in that direction.  However, if someone is to all appearances sincerely trying to engage with you at the level of sober rational argumentation, it is, morally and spiritually speaking, very dangerous glibly to dismiss that as a cover for some hidden evil motive.  It is, accordingly, especially regrettable that such “well poisoning” has today become routine in certain Catholic circles.  What could be a clearer violation of Christ’s command: “Judge not, lest you be judged”?  

This brings us to a third reason that the ad hominem fallacy is morally problematic, which is that it dehumanizes one’s opponents.   

Human beings are by nature rational animals.  What distinguishes us from other animals is that our activity is ultimately guided by intellect rather than merely by sensation, the appetites, or the passions.  Even when we pursue something that is pleasing to these faculties, that is only because our intellects grasp it as such.  Even when we act irrationally, we do not act non-rationally.  The intellect is malfunctioning, but that is different from not functioning at all.  

This is not only Aristotle’s teaching.  It is the teaching of the Catholic Church, and the reason the Church rejects fideism, voluntarism, and other forms of irrationalism.  In Libertas Praestantissimum, Pope Leo XIII writes:

[W]hile other animate creatures follow their senses, seeking good and avoiding evil only by instinct, man has reason to guide him in each and every act of his life…

[T]he will cannot proceed to act until it is enlightened by the knowledge possessed by the intellect.  In other words, the good wished by the will is necessarily good in so far as it is known by the intellect; and this the more, because in all voluntary acts choice is subsequent to a judgment upon the truth of the good presented, declaring to which good preference should be given.  No sensible man can doubt that judgment is an act of reason, not of the will. (Sections 3 and 5)

Similarly, in his famous Regensburg address, Pope Benedict XVI approvingly quotes Byzantine emperor Manuel II Palaeologus’s remark that “whoever would lead someone to faith needs the ability to speak well and to reason properly,” and endorses the emperor’s view that (as Benedict paraphrases Manuel) “not to act in accordance with reason is contrary to God’s nature.”  

Accordingly, when dealing with other human beings, we must always appeal to their reason as far as we can, because to fail to do so would be contrary to what is good for them given their nature.  Of course, sometimes this is not possible – for example, with a person who is literally insane, or with an attacker intent on inflicting bodily harm.  But it obviously is possible with an opponent who himself makes an effort at rational engagement.  

When, in response to such engagement, we resort to fallacious ad hominem rhetoric – when we ignore an opponent’s attempts to reason with us, when we respond to his arguments with mockery and contempt, when we try to shout him down and intimidate him into silence rather than persuading him – we treat him as something less than a rational animal, and therefore as less them human.  We are acting contrary to his nature, contrary to his human dignity.  This cannot fail to be sinful.  And the more greatly it contributes to sowing discord within society or the Church, the more gravely sinful it is.

Related posts:

What is an ad hominem fallacy?

Meta-bigotry

Meta-sophistry

Self-defeating claims and the tu quoque fallacy