From a debate I’m having with a friend: one of us maintains that ad homs are, by definition, irrelevant attacks on a person while the other maintains that all attacks on the person rather than the argument are ad hom.
I’ll use Bob Barr (R-GA [ret])in the following examples. The following is a clear ad hom:
Okay, the above is clearly an ad hominem because Barr’s personal life has nothing to do with the validity either way of his views or statements or claims on civil rights/privacy. On this we’re all clear. Here’s a slightly murkier example though:
In the above, I can see why it would be an ad hom to a degree, but it’s also relevant that Barr is a homophobe and has used bad information in arguing his cases about gays. Would the response be an ad hom?
Okay, in this one Barr’s private life is HIGHLY RELEVANT to Barr’s self confessed views on the subject of marriage and family. Is this still an ad hom?
Switching to a different famous American:
Pretty clearly an ad hom. Now this one:
Is the response an ad hom? Suppose if it lacked the second sentence?
Almost all of these are ad-homs. The point is that they don’t disprove the validity of the original statement. I’ll go through each of your examples, and maybe you’ll see what I mean:
All three may or may not be factual statements, but they do nothing to disprove the truth of the original statement. Thus, they are all ad-homs.
The “notorious homophobe” part is certainly an ad-hom; regardless of its relevancy it doesn’t disprove the original statement. The second half, that he has frequently used false facts, is not an ad-hom. However, it still does not disprove Barr’s statements, it merely casts doubt on them. In order to disprove them, the responder would need to identify which of the “facts” he cited were false and why, specifically, they were false, not rely on broad generalizations.
These are all ad-homs in this context. The only thing that they prove are Barr’s hypocrisy, but that is not relevant to the truth-value of his statements. It can both be true that marriage is the bedrock of society and that Barr is an adulterer, for instance, and it can be both true that he’s a pandering political opportunist and that gay marriage undermines marriage as an institution.
Perhaps not an ad-hom, interestingly, since the original statement was that “Thomas Jefferson was possibly the greatest president America ever had.” The fact that he was a slaveowner might disprove his greatness - in this case, since the original statement was about the personal character of someone, an attack on their personal character is not illogical.
Neither the statement nor the response is an ad-hom, since they are about Jefferson’s intentions. They can be paraphrased this way:
Statement: Thomas Jefferson kept slaves, which proves he was racist.
Response: Thomas Jefferson kept slaves, but that doesn’t prove he was racist.
Perfectly logical (although, it could use a warrant to the argument, such as a cite. But that’s a whole 'nother issue.)
First of all, let me say that I know nothing about American politics, and have never heard of the person in question. It’s possible that I’m misunderstanding what the argument is about. But, if I’ve understood you, the man speaks of family values, but is hoimself an adulterer. Therefore people dismiss what he says, because he doesn’t pracise what he preaches. Is that a fair summary, or have I misunderstood?
This is an example of tu quoque which is indeed a special form of ad hom.
By definition, they are attacks on the person, regardless of how relevant the person might be to the statement being discussed. (BTW, be careful to avoid attacking a fallacy of appeal to authority by committing ad hominem: “He’s a recognized expert!” “No, he doens’t know jack about it!”)
The response does nothing to attack the statement. If all we know about the argument is this statement, that the speaker is supporting the impeachment of Clinton and opposes gay marriage, then the response is ad hominem, since it does not directly address either of those issues.
I would posit, however, that if you are using the statement to bolster the assertion that Bob Barr is the epitome of morality and should be held as a model for the rest of us, then the response effectively demolishes that assertion.
One thing about ad hominems which has kind of bugged me:
Me: Do you have anything substantive to say on the global warming issue?
Idiot: La la la I can’t hear you peepeepoopookaka!
Me: Obviously you are a drooling moron with no coherent thought in your head.
Am I not justified in making the final remark? Can I have a debate about the ability (or non-) of someone to adequately debate a topic, or discuss his mental faculties in general, or not?
Actually, I came in here to make the opposite point–that in attacking an argument from authority is precisely when an ad hominem is legitimate. The whole point of an argument from authority is that the person’s testimony is justification-conferring because of the person’s expert status; so if you can show that he is not in fact an expert, you have undermined his argument (although you haven’t shown his conclusion is false.)
e.g.:
“Dr. X says that evolution is not supported by the scientific evidence.”
“But Dr. X is a known liar who cherry-picks evidence for creationism and repeatedly misrepresents the evidence for evolution. Besides, his PhD is in creative writing, not in any of the physical sciences.”
The third statement is not discussing whether marriage is in fact the bedrock of society, it’s whether Barr actually believes it to be so. His personal actions suggest that he either does not actually believe it to be so or he does not believe it applies to him. It’s not a complete argument, since his apparent hypocrisy does not necessarily negate his belief, but if it did, it would invalidate the claim that he voted based on that belief.
You’re completely justified in making the remark; it appears to be factual. But your remark provides no evidence or support for either position on global warming–just on someone’s mental faculties.
This might be true in a court of law but not in the court of deductive logic. Appeal to authority is a fallacy itself. The fact that an authority makes an assertion is not in itself proof of the assertion. Therefore it is unnecessary to attack their authority. Attacking their authority just trades one fallacy for another.
Perhaps you can clear something up for me about the appeal to authority (and I’m being serious, not sarcastic).
Does it matter whether the authority is speaking— well, as the Pope would call it, ex cathedra or not? For example, I can totally understand why saying
“Stephen Hawking is the world’s most brilliant physicist and he supports Candidate X in the next election”
would be a fallacy (expertise in physics doesn’t mean he’s an expert on politics)
But otoh if I were to say
“Stephen Hawking is the world’s most brilliant physicist and he believes in the existence of black holes”-
why would that be a logical fallacy? Astrophysics is something that Hawking absolutely is qualified to speak on and may well have written any book or paper that would supply evidence.
You should only cite authority to support your axioms, not to support your conclusions.
If you want to prove to a doubter the existence of black holes, then saying “Stephen Hawking believes in them” is a weak argument that would not convince your opposition. You have to actually reproduce Hawkings maths to prove their existence.
But if you want to discuss the formation of galaxies, advancing the idea that they form around black holes, then you can say “Black holes exist (see Hawking)” and reason from there to a conclusion.
It is not unreasonable for all practical purposes, but it is a logical fallacy with regard to deductive reasoning.
Logical fallacies are gaps in arguments that are intended to give proof, but which cannot logically serve as proof. The fact that an expert makes an assertion is not *proof * of the assertion, although it might reasonably convince most people in most circumstances that the assertion is probably true. That’s why the courts admit expert testimony.
Rigorous logic dealing with fallacies and whatnot is based on a small list of possibilities. There are things that must be true, things that might be true, and things that must not be true. Truly logical statements will identify things as one of those three.
So, Hawking’s math might prove that black holes must exist. Thus, citing this math as proof would be quite logical. However, citing Hawking because he is an expert is not proof, because it doesn’t prove that black holes must exist. One can conceive of the possibility that an expert on astrophysics could be incorrect on the existence of black holes. His status as an expert does not inherently make his statements factually 100% true. It certainly lends them rhetorical credibility, but this is not the same as truth which is all that formal logic is concerned with.
This is a key point. I’ve found most folks are hung up on the term “fallacy”, which they see strictly as a mistake of logic. Rather, many formal fallacies involve using the structure of a genuine argumentative form incorrectly. There was a recent thread which talked about this distinction with regard to the slippery slope fallacy: Although the “slippery slope argument” is a legitimate form of debate, the associated fallacy comes from using the form by itself to gloss over parts of the argument that need legitimate proof.
Ad Hominem is a similar type of formal fallacy based on a legitimate form of argument (though with this particular fallacy we also have the false baggage that ad hominem = “personal attack”). More correctly, an ad hominem argument is one in which the opponent’s ability to argue correctly is discredited as a means to discredit his/her argument. This is a legitimate tactic if the link between the opponent and the argument can be sufficiently supported. For example, if I claim my son is incredibly smart, you can legitimately challenge that claim with an ad hominem argument that I am his father, a fact that most of us would agree colors my judgment. If, however, you challenge my assertion “US government policy isn’t taking global warming seriously” by suggesting that I’m too much of an expert in French culture to know what’s going on in the US, then you’re committing the ad hominem fallacy. Notice that the two examples are similar, but in the second the link between “knowledge of US policy” and “expert in French culture” is not clear; the second example has the form of a legitimate argument, but is missing a necessary component.
I would respectfully disagree. Presumably most fathers would say that their sons are smart. But the mere claim by someone that “X is smart” is just that, a claim.
If you want to disprove that claim, it is meaningless to look at the motives of the person making the claim. It could be that your son is actually smart, regardless of who makes the claim.
The only way to disprove the claim is to show that the son is not smart, just as the only way to prove it is to show that the son is smart. A claim exists on its own, *independent of who made it. * For example, should we believe a scientist’s claim because he is a scientist? By no means, there’s been horrendous scientific errors, mistaken claims, and even scientific fraud. If anyone has a vested interest in a claim, it’s the person who made it, regardless of whether it’s a father talking about his son, or a scientist talking about his pet theory.
Indeed, this is why evidence of past crimes is not allowed in a court of law. Yes, a man might have stolen before … but that does not mean he stole in this particular instance. When one is trying to determine the truth of a claim, whether the claim was made by a physician, a priest, or a pervert means nothing. The claim is either true, or it is not. All the rest is just window dressing.
This is all true, but very little of our reasoning regarding matters of fact is deductive. And in fact when it comes to our knowledge of the world, much (perhaps most) of our knowledge is based on the testimony of others. So authority, and the legitimacy thereof, looms large. But yeah, if **Sampiro ** was asking about deductive logic, then ad hominem is always fallacious.
But, to reiterate CJJ*'s point (I think,) the important thing to notice is that when someone says “But you’re the kid’s dad!” they’re not trying to disprove the claim. Rather, their trying to cast what might be called “reasonable doubt” on the claim. It would be a formal or logical fallacy if it was intended as an argument disproving the claim “My son is smart,” but if it was not intended to disprove the claim, then no (formal or logical) fallacy was committed.
Frylock, thanks for the explanation. I’m not sure I’m clear on the difference between attempting to disprove something and casting doubt on something, but it kinda makes sense.