A little logic is a dangerous thing
Some famousand lovely lines from Alexander Pope’s “An Essay on Criticism” observe:A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring.
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
Think of theperson who has read one book on a subject and suddenly thinks he knowseverything. Or the beginning student ofphilosophy whose superficial encounter with skeptical arguments leads him todeny that we can know anything. A deeperinquiry, if only it were pursued, would in each case yield a more balancedjudgement.
Similardelusions of competence often afflict those who have studied a littlelogic. ElsewhereI’ve discussed the phony rigor often associated with the application of formalmethods. Here, however, what I have inmind is the abuse of a more elementary part of logic – the study of fallacies(that is to say, of common errors in reasoning).
The principle of charity
Beginningstudents of logic, when they first learn the fallacies, often start thinkingthey can see them everywhere – or more precisely, everywhere in the argumentsof people whose opinions on politics or religion they already disagree with,though not so much in the arguments of people on their own side. (What are the odds?) A good teacher will inform them thatknowledge of the fallacies must be applied in conjunction with what is calledthe “principle of charity.” Thisprinciple tells us that, when an argument that could be read as committing a fallacy could also be plausiblyinterpreted instead in a different way, we should presume that the latter interpretationis the correct one.
The point ofthis principle is not merely, or even primarily, to be nice. The point is rather that the study of logicis ultimately about pursuing truth,not about winning a debate. If wedismiss some argument too quickly because we haven’t considered a more charitableinterpretation, then we might miss out on learning some important truth –perhaps a truth that we are reluctant to learn, precisely because it comes fromsomeone we dislike.
But it’s notjust a failure to apply the principle of charity that can lead someone wronglyto accuse another of committing a fallacy. Sometimes people just don’t correctly understand the nature of someparticular fallacy.
Ad hominem?
Let’sconsider some common examples, beginning with the ad hominem fallacy. Whatmatters when evaluating an argument is whether its premises are true, andwhether the conclusion really follows from the premises, either with deductivevalidity or at least with significant probability. And that’s all that matters, logically speaking. The character of the person giving theargument is entirely irrelevant to that. Ad hominem fallacies arefallacies that neglect this fact – that pretend that by attacking a person insome way, you’ve thereby cast doubt on the argument the person has given or thetruth of some claim he has made.
There aredifferent ways this might go. Thecrudest way is the abusive ad hominem,wherein, instead of addressing the merits of some argument the person hasgiven, you simply call him names – “racist,” “fascist,” “commie,” or whatever –and pretend that sticking such a label on him casts doubt on what he said. Another common variation on the ad hominem fallacy is the circumstantial ad hominem or appeal to motive, wherein one attributesa suspect motive to the person and pretends that doing so casts doubt on whatthe person says. Of course, it doesnot. A good argument remains a goodargument, however bad the motives (or alleged motives) of the person giving it,and a bad argument remains a bad argument however good the motives of theperson giving it.
It iscrucial to emphasize, though, that calling someone a name, attributing badmotives to him, or in some other way attacking a person or his character is not in itself a fallacy. It amounts to a fallacy only when what is at issue, specifically, is themerits of some claim he made or some argument he gave, and instead ofaddressing that, you change the subject and attack theperson.
But ofcourse, there are other contexts where the subject is the person or his character, rather than some argument he gave. For example, if a jury is trying to determinewhether a person’s eyewitness testimony is reliable, a lawyer is not committingan ad hominem fallacy if he notesthat the witness has been caught in lies in the past, or is known to harbor apersonal grudge against the person he’s testifying against. Or, when you are deciding whether to believea used car salesman, you are not guilty of an ad hominem fallacy when considering that his motive to sell you acar might bias the advice he gives you. Again, in cases like these, what is at issue is not some argument theperson gave, which might be considered entirely apart from him. What is at issue is the credibility of theperson himself.
Or supposeyou call someone a “jerk” precisely because he is acting like a jerk. There is no fallacy in that. Indeed, there is no fallacy even if he is not acting like a jerk, but you’re justin a bad mood. Name-calling may bejustified in the one case and unjustified in the other, but it is not a fallacy if the context isn’t one wherethe cogency of some argument he gave is what at issue, and you’re distractingattention from that.
People areespecially prone to make the mistake of confusing attacks on a person with the ad hominem fallacy when the context is adebate or public exchange of some other kind – where, of course, one or bothsides may be making arguments. SupposePerson A and Person B are engaged in some public dispute (on a blog, onTwitter, or wherever). Suppose Person Aaddresses the arguments of Person B, but Person B refuses to respond in kind,resorting instead to ad hominemattacks, or mockery, or changing the subject. Suppose that Person A, appalled by this behavior, calls attention toPerson B’s personal failings – characterizing Person B as intellectuallydishonest, or as a sophist, or as a buffoon, or the like. And suppose that Person B then objects tothis and accuses Person A of committingan ad hominem fallacy.
Is Person Aguilty of such a fallacy? Of coursenot. He has not attacked Person B as a way of avoiding addressing PersonB’s claims or arguments. On thecontrary, he has addressed those claimsand arguments. His negative estimation ofPerson B’s character is a separatepoint, and a correct one. Person B – whether out of cluelessbefuddlement or cynical calculation – makes of the false accusation that PersonA is guilty of an ad hominem fallacya smokescreen to hide the fact that it is really Person B himself who is guilty of this.
In the caseI just described, a person is accused of committing an ad hominem fallacy when he is notin fact doing so. But it can also happenthat a person pretends (or maybe even sincerely believes) that he is notcommitting an ad hominem fallacy whenhe is fact doing so. To change my example a bit, suppose Person Aand Person B are engaged in some public dispute. Suppose Person B never addresses Person A’sarguments, but simply and repeatedly flings terms of abuse, questions hismotives, and so on, with the aim of undermining Person A’s credibility with hisreaders. Suppose Person A accuses PersonB of ad hominem fallacies, and PersonB responds: “I’ve committed no such fallacy! After all, using such terms of abuse is not by itself fallacious. It’s only a fallacy when addressing anargument, and I haven’t beenaddressing your arguments. I’m justtelling people what a horrible person you are.”
Is Person Bthus innocent of an ad hominemfallacy in this case? Not at all. He may not have committed this fallacy in a direct way, but he has still done so indirectly. True, he has avoided addressing any specific argument Person A hasgiven. Hence he has not in that way committed an ad hominem fallacy. At the same time, though, he has, through ad hominem abuse, tried to poison hisreaders’ minds against taking seriously anyargument that Person A might happen to give. Hence he has deployed a fallaciously adhominem tactic in a general way.
The bottomline is this. Is a speaker resorting to ad hominem abuse as a way of trying to avoid having to address some claim orargument another person has given? Ifso, he is guilty of an ad hominemfallacy. If not, then he is not guiltyof such a fallacy (whether or not his abusive language is unjustifiable forsome other reason – that’s a separatequestion).
Appeal to emotion?
An appeal to emotion fallacy is committedwhen, instead of trying to convince one’s listener of a certain conclusion byoffering reasons that provide actual logical support for that conclusion, oneplays on the listener’s emotions. The strengthof the emotional reaction makes the conclusion seem well-supported, when in fact the premises do not providestrong grounds for believing it.
But here itis important to emphasize that the presence of an emotional reaction does notby itself make an argumentfallacious, not even if the speaker foresees such a reaction and indeed even ifhe intends it. To take an artificial examplein order to illustrate the point, suppose some follower of Socrates, havingjust heard the fatal verdict, wants desperately to believe that his heroSocrates will somehow never die. Youhope to bring him back to reality, and present him with the following argument:
All men are mortal
Socrates is a man
Therefore, Socrates is mortal
He contemplates this reasoning, sighs heavily and resignshimself to the cold, hard truth. Theargument raises profound emotions in him, as you knew it would. But have you committed a fallacy of appeal toemotion? Obviously not. The argument is no less sound than it wouldbe if someone with no emotional reaction at all had heard it.
Still, you might think, the reason there is no fallacy hereis that the emotions in question are not such as to incline the person to want to believe the conclusion. Quite the opposite. But suppose the emotions in question were of that sort. For example, suppose one of Socrates’ enemiesfeared that the hemlock would not kill him, and worried that perhaps Socrateswas immortal and could never be gotten rid of. Suppose you present him withthe same argument just given. He isreassured. But have you now, in thiscase, committed a fallacy of appeal to emotion?
No. Here too, theargument remains just as sound as it would be if some unemotional person who couldn’tcare one way or the other about Socrates had heard it. But what if you not only know that the personwill be pleased by the conclusion, but intendfor him to be pleased by it? What ifyou hope that his positive emotional response to the argument will make himmore likely to accept it? Wouldn’t that make it a fallacious appeal toemotion?
No, it would not. Forthe bottom line is that the premises are clearly true and the conclusionclearly follows validly from them. Thepresence or absence of an emotional reaction, of whatever kind, does not changethat in the least. Hence there is nofallacy of appeal to emotion. Such afallacy is committed only when there is some logical gap in the support the premises supply the conclusion,which the emotional reaction is meant to fill. But there is no such gap – and thus no fallacy.
Indeed, an emotional reaction can in some cases get a personto be more rational, not less. In the second example, the person’s fear thatSocrates might be immortal is unreasonable. He’s letting his fear of Socrates’ influence within Athens get the betterof him, and lead him to paranoid delusions. The argument you give him, preciselybecause it is pleasing to him, draws his attention away from these paranoidfeelings and back to reality.
Again, the example is admittedly artificial. But there are many topics that dorealistically carry heavy emotional baggage, yet where this does not entailthat arguments having to do with them must be guilty of the fallacy of appealto emotion. Matters of life and death –war, abortion, capital punishment, and the like – are like that. No matter what conclusions you draw and whatpremises you appeal to, they are bound to generate emotional reactions of somekind in your listener. But that does notentail that you are guilty of a fallacy of appeal to emotion.
The bottom line is this. Are the premises of the argument true? Do they in fact provide logical support for the conclusion (whetherdeductive validity or inductive strength)? Then the argument is not guilty of a fallacy of appeal to emotion,whether or not it also happens to generate an emotional reaction in thelistener, and whatever that reaction happens to be.
Slippery slope?
A third fallacy that is widely misunderstood is the slippery slope fallacy. Someone commits this fallacy when he claimsthat a certain view or policy will lead to disastrous consequences, but withoutoffering adequate support for this judgement. It is an instance of the more general error of jumping to conclusions orinferring well beyond what the evidence appealed to would support.
For example, suppose someone criticized a proposed small taxhike by claiming that it would inevitably lead to a radically egalitarian redistributionof wealth. It is hard to imagine howthis would fail to count as a slippery slope fallacy. Is there a logical connection between raising taxes slightly and radicallyequalizing shares of wealth by way of redistribution? No, and itis not hard to formulate principles that would both allow for some taxation while at the same time rulingout radically redistributive taxation. Isthere nevertheless some strong causal connectionbetween raising taxes slightly and radically redistributing wealth? Obviously not, since there have as a matterof historical fact been many cases where taxes were raised, but were neverfollowed by a radically egalitarian redistribution of wealth.
Notice that the problem here, though, is not that the argument claims that bad consequences wouldfollow. The problem is that the argumentdid not back up this claim. This is often overlooked by people who accuseothers of the slippery slope fallacy. They seem to think that anyclaim that bad consequences will follow from a certain view or policy amountsto a slippery slope fallacy.
In fact, there is no fallacy as long as someone explains exactly how the bad consequences aresupposed to follow. If you can show thatA logically entails Z, or that itdoes so when conjoined with some other clearly true assumptions, then you havenot committed a slippery slope fallacy. Or if you can identify some specificcausal mechanism by which A will lead to Z, then you have not committed aslippery slope fallacy. You commit such afallacy only when you jump from A to Z withoutfilling in the gap between them.
What if you are wrong about the claim that A logicallyentails Z, or wrong about the causal mechanism you claim links them? You are still not guilty of a slippery slopefallacy. True, you are mistaken, and perhaps guilty of someother logical error. But you haven’tcommitted a slippery slope fallacy,specifically, if you at least proposed some specific means by which A wouldlead to Z.
There are other fallacies too that are often misunderstood,but that suffices to make the point. Knowledge of the fallacies is essential to reasoning well, but it is oflimited value if it is merely superficialknowledge, and may in that case even impede careful reasoning. It can lead to seeing fallacies where they donot exist, and thus lead away from truth rather than toward it. And if one’s knowledge of fallacies isdeployed merely as a further rhetoricalmeans of trying to make an opponent look bad, it constitutes sophistry rather than remedying sophistry.
Furtherreading:
Thead hominem fallacy is a sin
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