# The Logical Fallacy "ad hominem" and others, and How to Debate **URL:** \ **Category:** Great Debates\ **Created:** [December 7, 2010, 11:52pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355 "2010-12-07T23:52:50Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![fuzzypickles](https://avatars.discourse-cdn.com/v4/letter/f/9d8465/32.png) [@fuzzypickles](https://boards.straightdope.com/u/fuzzypickles)\ **Post date:** [December 8, 2010, 9:33pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/21 "2010-12-08T21:33:17Z")
tl;dr (not _ad hominem_, but a statement of fact.) ---
**Author:** ![athelas](https://avatars.discourse-cdn.com/v4/letter/a/5e9695/32.png) [@athelas](https://boards.straightdope.com/u/athelas)\ **Post date:** [December 8, 2010, 9:54pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/22 "2010-12-08T21:54:04Z")
> [@elucidator](#): > > And an \*ad hominem \*remark can also be a medium for humor, and a good laugh is the most sanity promoting experience we have available. One definition of “sanity” is _believing what is true_. But mockery can attack truth and falsehood equally well. What makes mockery work is the rhetorical skill or charisma of the teller, not the merit of the argument attacked. So mockery is entirely orthogonal to truth - unlike, say, the standards of reproducibility and falsifiability, which specifically hurt false claims. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [December 10, 2010, 7:33am UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/23 "2010-12-10T07:33:25Z")
> [@Stoid](#): > > And in this case…works how? What does it succeed in doing? “Winning” the debate? By what definition? In the sense that it succeeds in persuading the people listening to me to take my side. Something that’s important to remember about logical fallacies is that’s what they are, logical fallacies. That doesn’t mean that they can’t be used as rhetorical tools. As another example, celebrity endorsements are an example of an appeal to authority, and logically, don’t make any sense. George Foreman, I think it’s safe to say, doesn’t have any experience making grills…he’s not some grilling engineer. So there’s no real logical reason to assume that a grill with Foreman’s name on it would be better than one without his name on it. But still, there will be some people who will buy the George Foreman Grill because his name is on it. So, in that sense, putting his name on it “works”. The grill people will sell more grills. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [December 10, 2010, 3:21pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/24 "2010-12-10T15:21:47Z")
People sometimes forget that an ad hom isn’t necessarily a logical fallacy. Attacting the credibility or partiality of a person isn’t a fallacy under all circumstances. It is perfectly valid where that person has put their own credibility at issue in some way, explicitly or implicitly - either by making themselves a source of fact, or relying on some sort of expertise. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [December 10, 2010, 3:40pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/25 "2010-12-10T15:40:29Z")
> [@Malthus](#): > > People sometimes forget that an ad hom isn’t necessarily a logical fallacy. Attacting the credibility or partiality of a person isn’t a fallacy under all circumstances. It is perfectly valid where that person has put their own credibility at issue in some way, explicitly or implicitly - either by making themselves a source of fact, or relying on some sort of expertise. When is an ad homenim not a logical fallacy? Cam you give an example? ---
**Author:** ![Diogenes\_the\_Cynic](https://avatars.discourse-cdn.com/v4/letter/d/e99b99/32.png) [@Diogenes\_the\_Cynic](https://boards.straightdope.com/u/Diogenes_the_Cynic)\ **Post date:** [December 10, 2010, 3:43pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/26 "2010-12-10T15:43:22Z")
> [@Really\_Not\_All\_That\_Bright](#): > > Meh. Ad hominem arguments are used all the time in law, only they’re called impeachment. The credibility of parties in a debate may not be a legitimate topic of discussion, but the credibility of their sources certainly is. Attacking the credibility of their sources would not be _ad hominem_. ---
**Author:** ![elucidator](https://avatars.discourse-cdn.com/v4/letter/e/8edcca/32.png) [@elucidator](https://boards.straightdope.com/u/elucidator)\ **Post date:** [December 10, 2010, 3:48pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/27 "2010-12-10T15:48:17Z")
Oh, sure, you would say that! ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [December 10, 2010, 3:56pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/28 "2010-12-10T15:56:44Z")
> [@Captain\_Amazing](#): > > When is an ad homenim not a logical fallacy? Cam you give an example? Certainly. Any time that the personal facts concerning the speaker are, in fact, relevant to the argument. The classic is as a counter to use of authority. “I’m a physician, and I know from my working experience that this government health care plan will not work.” “But Bill, being a physician, you aren’t impartial. You will get less money if this health care plan passes.” The second speaker is casting doubt on the first because of who he is - an ad hom - but it isn’t a _fallacious_ ad hom. The first speaker put his credibility in issue, since it backs up his argument. The audience isn’t wrong to weigh Bill’s expertise against his motives, since it is quite possible that Bill actually knows as an expert that the government’s plan will work, but is choosing to lie about it because it is in his best interests. ---
**Author:** ![Blaster\_Master](https://avatars.discourse-cdn.com/v4/letter/b/cab0a1/32.png) [@Blaster\_Master](https://boards.straightdope.com/u/Blaster_Master)\ **Post date:** [December 10, 2010, 4:06pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/29 "2010-12-10T16:06:00Z")
> [@Captain\_Amazing](#): > > When is an ad homenim not a logical fallacy? Cam you give an example? I think the point he’s trying to make is if, for instance, someone says “I am an expert in X, therefore Y” and you can attack his expertise in X then you have at least some validity when you claim it undermines his assertion of Y. The problem is, that claim is a logical fallacy of appeal to authority in the first place. In either case, even if you prove that he is completely ignorant on topic X, it doesn’t prove one way or the other whether Y is true or not, all you did was counter a bad argument with another bad argument. Hell, a kid who dropped out of high school at 16 can falsely claim to be an expert in physics and appeal to that when making a claim about gravitational theory, it’s entirely possible that he isn’t an expert but that his claim is still absolutely accurate. In either case, I approve of the OP and agree with the observation that ad hominem is often overused. In fact, it often seems that ad hominem being used incorrectly, as well as other commonly referenced logical fallacies, results in either sidetracking the debate or potentially falsely rejecting a valid argument. Is there a logical fallacy for incorrectly applying a logical fallacy? I think it’s amusingly ironic enough that, though it is just a subset of a red herring, that it still deserves its own name. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [December 10, 2010, 4:21pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/30 "2010-12-10T16:21:40Z")
To expand on what **Malthus** said, source/poster credibility and behavior can be a legitimate part of responding to claims. Take as an example a poster or website which has a long history of anti-science rhetoric or bigotry, and which posts a long series of cherry-picked quotes and references designed to advance a particular argument (i.e. a [“Gish gallop”](http://rationalwiki.org/wiki/Gish_Gallop)). It is perfectly legitimate in my view to refute a portion of the arguments made while commenting on the historical inaccuracies and bad motives of the person/site involved. It is not always necessary or possible to tackle every single allegation they make. While this thread was ostensibly started to educate us on the meaning of _ad hominem_, a quote cited in the OP recapitulates another fallacy: > [@](#): > > First, logical reasoning is not an absolute law which governs the universe. Many times in the past, people have concluded that because something is logically impossible (given the science of the day), it must be impossible, period. It was also believed at one time that Euclidean geometry was a universal law; it is, after all, logically consistent. Again, we now know that the rules of Euclidean geometry are not universal. Logical reasoning together with compelling evidence are the tools rational people use to evaluate the world around them. “Science wuz wrong before!” is a fallacious argument used to advance woo; fallacious because 1) science is self-correcting, whereas woo is not, and 2) every argument needs to be taken on its merits, and is not accorded respect simply because another (initially rejected) argument was subsequently proven to be correct. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [December 10, 2010, 4:27pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/31 "2010-12-10T16:27:57Z")
Well, but in that case, neither side is making an argument. The one person is just making a bald assertion “My experience as a physician proves that government health care won’t work”, and the other is just questioning the other person’s motives. “As a physician, you’d lose money with government health care.” Neither is making a logical argument. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [December 10, 2010, 4:38pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/32 "2010-12-10T16:38:47Z")
> [@Blaster\_Master](#): > > I think the point he’s trying to make is if, for instance, someone says “I am an expert in X, therefore Y” and you can attack his expertise in X then you have at least some validity when you claim it undermines his assertion of Y. The problem is, that claim is a logical fallacy of appeal to authority in the first place. In either case, even if you prove that he is completely ignorant on topic X, it doesn’t prove one way or the other whether Y is true or not, all you did was counter a bad argument with another bad argument. > > Hell, a kid who dropped out of high school at 16 can falsely claim to be an expert in physics and appeal to that when making a claim about gravitational theory, it’s entirely possible that he isn’t an expert but that his claim is still absolutely accurate. A non-fallacious ad hom can be used even where the expertise the purported expert is relying on is perfectly genuine and relevant. An appeal to authority (if it can be substantiated), and a non-fallacious ad hom, are neither one of them inherently “bad arguments”. One uses experts because of their expertise. Attacking their motives _can be_ a reasonable counter to that expertise (again, if it can be substantiated). An ad hom is fallacious where it has, as it were, nothing to do with the validity of the argument being attacked. For example, take the ad hom in the OP: > [@](#): > > Bill: “I believe that abortion is morally wrong.” > Dave: “Of course you would say that, you’re a priest.” > Bill: “What about the arguments I gave to support my position?” > Dave: “Those don’t count. Like I said, you’re a priest, so you have to say that abortion is wrong. Further, you are just a lackey to the Pope, so I can’t believe what you say.” The “arguments” are not described, and presumably have nothing to do with Bill’s expertise and experiences as a priest. Change that presumption, and it isn’t so clearly a fallacious ad hom. Example: > [@](#): > > Bill: “I believe that abortion is morally wrong.” > Dave: “Of course you would say that, you’re a priest.” > Bill: “What about those arguments I gave to support my position - that in my education as a priest, I’ve been trained to understand what morality truly is, to be an arbiter of morality in the community, and so to really know that it’s morally wrong?” > Dave: “Those don’t count. Like I said, you’re a priest, so you have to say that abortion is wrong. Further, you are just a lackey to the Pope, so I can’t believe what you say.” ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [December 10, 2010, 4:41pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/33 "2010-12-10T16:41:46Z")
> [@Captain\_Amazing](#): > > Well, but in that case, neither side is making an argument. The one person is just making a bald assertion “My experience as a physician proves that government health care won’t work”, and the other is just questioning the other person’s motives. “As a physician, you’d lose money with government health care.” Neither is making a logical argument. In the real world, few arguments are made based on logic alone. Generally speaking, arguments tend to consist of _facts_ plus logic. A non-fallacious ad-hom is one where some aspect of the identity of the person making the argument is important to the _factual_ basis of the argument. ---
**Author:** ![Damuri\_Ajashi](https://avatars.discourse-cdn.com/v4/letter/d/898d66/32.png) [@Damuri\_Ajashi](https://boards.straightdope.com/u/Damuri_Ajashi)\ **Post date:** [December 10, 2010, 4:49pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/34 "2010-12-10T16:49:51Z")
I’d like to think that the purpose of debate on this board is to increase knowledge and understanding but too many people simply want to win. They never admit when the other peson has made a good point, instead they look for nits to pick while ignoring the greater point being made. Some people are worse offenders than others. ---
**Author:** ![Blaster\_Master](https://avatars.discourse-cdn.com/v4/letter/b/cab0a1/32.png) [@Blaster\_Master](https://boards.straightdope.com/u/Blaster_Master)\ **Post date:** [December 10, 2010, 5:40pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/35 "2010-12-10T17:40:10Z")
> [@Malthus](#): > > A non-fallacious ad hom can be used even where the expertise the purported expert is relying on is perfectly genuine and relevant. > > An appeal to authority (if it can be substantiated), and a non-fallacious ad hom, are neither one of them inherently “bad arguments”. One uses experts because of their expertise. Attacking their motives _can be_ a reasonable counter to that expertise (again, if it can be substantiated). I’m not sure I can agree with that. I see appealling to an expert more as a shorthand to avoid reinventing the wheel. Whenever you appeal to an expert, it’s really only a valid in the context of the argument if all parties involved in the discussion accept that individual as an expert and, thus, trust the processes they went through to reach a particular conclusion. The problem is, just because an expert said something doesn’t necessarily mean that it’s correct. As an example, I’m inclined to take a study published in a reputable journal as an authoritative source and, if they results of such a study are brought up in a debate, I’m likely to accept the conclusions as valid, but it’s still entirely possible that there’s issues with a given study that was published and, in fact, it’s conclusions are incorrect. It’s just a huge waste of time and usually fruitless to argue about the methodology and conclusions of reputed experts, but it still ultimately boils down to “because he said so.” And this is exactly why an attack on the expert is a reasonable response. If one person doesn’t accept a source as an authority on a subject, all they’re really doing is rejecting the “because he said so” part of it, it still doesn’t actually address the veracity of the conclusions of that source. To carry a similar example, imagine one person puts forth a study in a journal I don’t find reputable and I attack that journals reputation. It’s a valid counter to accepting something in that journal on a “because it said so” basis, but it’s still entirely possible that a given study published in that journal uses valid metholodology and reaches a solid conclusion. Ultimately, neither is technically a truly 100% logical argument because it doesn’t always follow that an expert is 100% correct on every part of a subject or that someone who doesn’t know what they’re talking about hasn’t, even if by pure chance, reached an accurate conclusion on the given topic. It’s still generally accepted in debate because the probability of an expert reaching a valid conclusion is generally very high and a person who isn’t an expert is less likely to reach a valid conclusion, but when you boil it down it’s still just “because I said so” and “you don’t know what you’re talking about” and the validity of the conclusion is ultimately independent of either of those factors. > [@](#): > > An ad hom is fallacious where it has, as it were, nothing to do with the validity of the argument being attacked. > > For example, take the ad hom in the OP > > … > > The “arguments” are not described, and presumably have nothing to do with Bill’s expertise and experiences as a priest. > > Change that presumption, and it isn’t so clearly a fallacious ad hom. I agree with you, that attacking the source of the argument as being a priest, which so happens to also be one of the participants, is a reasonable response if his argument specifically pertains to the expertise of that source as a priest. At it’s core, that argument is essentially “I’m an expert on the topic” with a response of “no you’re not”. In essence, the priest is asking the other person to accept that his training as a priest taught him about morality and all that, and the other person isn’t accepting it. However, just like with the study example above, the priest ought to be able to, when his expertise is questioned, skip that shorthand argument and actually go through the methodology of how he reached those particular conclusions. Ultimately, with that argument, whether or not abortion is morally wrong is independent of whether that individual is a priest or not, so refuting that his priesthood makes him an expert or not still technically has no bearing on the veracity of the argument So, in short, yes I agree that there are situations when an ad hominem argument is a reasonable response in a debate, but it’s still going to always be fallicious because, while there is often a very strong correlation between the credibility of a source and the validity of it’s conclusions, it is not an absolute correlation. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [December 10, 2010, 5:40pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/36 "2010-12-10T17:40:18Z")
> [@Malthus](#): > > In the real world, few arguments are made based on logic alone. Generally speaking, arguments tend to consist of _facts_ plus logic. > > A non-fallacious ad-hom is one where some aspect of the identity of the person making the argument is important to the _factual_ basis of the argument. But when is the identity of the person making the argument important to the factual basis of the argument? A statement is factually true or false, no matter who makes it. ---
**Author:** ![Paranoid\_Randroid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/paranoid_randroid/32/18_2.png) [@Paranoid\_Randroid](https://boards.straightdope.com/u/Paranoid_Randroid)\ **Post date:** [December 10, 2010, 5:59pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/37 "2010-12-10T17:59:09Z")
> [@elucidator](#): > > Oy! Judaism is the punk rocking-est religion, isn’t it? ---
**Author:** ![Bosstone](https://avatars.discourse-cdn.com/v4/letter/b/22d042/32.png) [@Bosstone](https://boards.straightdope.com/u/Bosstone)\ **Post date:** [December 10, 2010, 6:05pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/38 "2010-12-10T18:05:13Z")
> [@Captain\_Amazing](#): > > But when is the identity of the person making the argument important to the factual basis of the argument? A statement is factually true or false, no matter who makes it. Resolved: I am the Queen of Scotland. It’s not ad hom to then tell me I’m some silly bugger posting from work. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [December 10, 2010, 6:26pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/39 "2010-12-10T18:26:09Z")
Ok, the statement, “I am X” is one case. But saying “You’re just some guy posting from work” isn’t an ad hom. statement at all. It’s a factual statement directly rebutting your claim that you’re the Queen of Scotland. It’s not a “non-fallacious ad-hom”. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [December 10, 2010, 6:35pm UTC](https://boards.straightdope.com/t/the-logical-fallacy-ad-hominem-and-others-and-how-to-debate/563355/40 "2010-12-10T18:35:19Z")
> [@Blaster\_Master](#): > > I’m not sure I can agree with that. I see appealling to an expert more as a shorthand to avoid reinventing the wheel. Whenever you appeal to an expert, it’s really only a valid in the context of the argument if all parties involved in the discussion accept that individual as an expert and, thus, trust the processes they went through to reach a particular conclusion. The problem is, just because an expert said something doesn’t necessarily mean that it’s correct. > > As an example, I’m inclined to take a study published in a reputable journal as an authoritative source and, if they results of such a study are brought up in a debate, I’m likely to accept the conclusions as valid, but it’s still entirely possible that there’s issues with a given study that was published and, in fact, it’s conclusions are incorrect. It’s just a huge waste of time and usually fruitless to argue about the methodology and conclusions of reputed experts, but it still ultimately boils down to “because he said so.” > > And this is exactly why an attack on the expert is a reasonable response. If one person doesn’t accept a source as an authority on a subject, all they’re really doing is rejecting the “because he said so” part of it, it still doesn’t actually address the veracity of the conclusions of that source. To carry a similar example, imagine one person puts forth a study in a journal I don’t find reputable and I attack that journals reputation. It’s a valid counter to accepting something in that journal on a “because it said so” basis, but it’s still entirely possible that a given study published in that journal uses valid metholodology and reaches a solid conclusion. > > Ultimately, neither is technically a truly 100% logical argument because it doesn’t always follow that an expert is 100% correct on every part of a subject or that someone who doesn’t know what they’re talking about hasn’t, even if by pure chance, reached an accurate conclusion on the given topic. It’s still generally accepted in debate because the probability of an expert reaching a valid conclusion is generally very high and a person who isn’t an expert is less likely to reach a valid conclusion, but when you boil it down it’s still just “because I said so” and “you don’t know what you’re talking about” and the validity of the conclusion is ultimately independent of either of those factors. Well, way I’d put it is this: the fact that “Bob” is an expert on a subject under discussion gives Bob some credibility when he makes pronouncements on it. Obviously, that does not create an irrebuttable assumption that Bob is in fact right. There may be many reasons Bob is wrong, and can be shown to be wrong. Most of them are irrelevant to this analysis - for example, you could confront Bob’s pronouncement with that of another, equally credible expert, or point out that Bob is starting his analysis with the wrong set of assumptions. However, one way to attack Bob’s prononcements is to impeach his credibility as an expert. Normally, this would be an “ad hom”. If the argument were purely one based in logic, a fallacious ad-hom. You have mentioned one method - to demonstrate s/he is, in fact, not really an expert. Another, available even if everyone agrees s/he _is_ really an expert, is to demonstrate s/he’s not really impartial - that s/he has reason, other than his or her actual expertise, to pronounce as s/he does. It is for this very reason that (say) some medical journals require researchers to publish conflict-of-interest statements. In short, it is not a hard-and-fast sort of rule, but part of the messy task of evaluating evidence. > [@](#): > > I agree with you, that attacking the source of the argument as being a priest, which so happens to also be one of the participants, is a reasonable response if his argument specifically pertains to the expertise of that source as a priest. At it’s core, that argument is essentially “I’m an expert on the topic” with a response of “no you’re not”. In essence, the priest is asking the other person to accept that his training as a priest taught him about morality and all that, and the other person isn’t accepting it. However, just like with the study example above, the priest ought to be able to, when his expertise is questioned, skip that shorthand argument and actually go through the methodology of how he reached those particular conclusions. I’d put it slightly differently, and sum it up as follows: Bill: ‘my training as a priest gives me expertise in morality. Therefore, my pronouncements on the morality of this issue carry greater weight.’ Dave: ‘On the contrary, your training as a priest fetters your analysis, since there is only one conclusion you can come to, regardless of evidence, and remain a priest in good standing with the Church. Therefore, your pronouncements on the morality of this issue should carry little or no weight.’ > [@](#): > > Ultimately, with that argument, whether or not abortion is morally wrong is independent of whether that individual is a priest or not, so refuting that his priesthood makes him an expert or not still technically has no bearing on the veracity of the argument In the abstract, this is certainly true. But whether a particular tactic is a “fallacy” has to be weighed in the context of the actual debate between Bill and Dave. > [@](#): > > So, in short, yes I agree that there are situations when an ad hominem argument is a reasonable response in a debate, but it’s still going to always be fallicious because, while there is often a very strong correlation between the credibility of a source and the validity of it’s conclusions, it is not an absolute correlation. See, I don’t follow this. There is no need for there to be an absolute correlation for an ad hom to be non-fallacious. 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