Ad Verecundiam

"I am right because I say so or because X says so."

The argument from authority is the weakest form of argument, according to Boethius. -- St. Thomas Aquinas


An argumentum ad verecundiam is an argument based on authority. The Latin means "appeal to reverence".

(Here, authorities mean people presumed to be experts, as opposed to people holding power over others--ScottJohnson)

Note that quoting scientific papers (in particular, ones that have survived peer review and other forms of professional scrutiny from the scientific community) is not AdVerecundiam. Repeating conjectures that are offered by scientists or other authorities when the conjecture is not supported by formal study, is AdVerecundiam. (See below).

Example: "UFOs are not real, because the great CarlSagan said so."

It's not so much because of the peer review of the paper, but because it is supposed that the paper documents the actual observations and evidence, i.e. it contains its own propositions that the petitioner and respondent of an argument may agree upon as true (and if they don't, it may be outside the scope of logic to determine the truth). One must appeal to the content of the paper to present a valid argument, not to the fact that it's peer-reviewed. // Had I bothered to read a little more, I would have noticed that this point was already made :p

Fallacious because:

(Following would seem to be arguments against AdAutoritatem?...)

This is not so clear. Many academics/intellectuals know more that the average person about a lot of subjects beyond there area of expertise, because they tend to get interested in things and spend the time --- moreso that average. The also tend to be more intelligent and better educated than average, which can make gaining such knowledge much more efficient. The fallacy is not in thinking that random expert might have a good opinion on Y, even though she is an expert in X, it is that thinking that her expertise in X is transferrable (of course it isn't).

Sometimes correct, because: However, appealing to authority may be a good HeuristicRule.

I like the distinction that experts' words have no more weight than anyone else's, but they are useful because they can provide information or answers or arguments _and_ the reasons, background and whatever else are required to back it up. Or at the very least references to sources that do.


In circumstances when neither participant is an expert in the field, an ArgumentFromAuthority can have value. Examples:

Grandpa: "I've just been bitten by a snake - I think I'd better soak in cold water"

Grandma: "No, my folks always said that you should put vinegar on it, what do you think Mary?"

Mary: "Well, that TV doctor said you should go straight to hospital - I guess he knows best"

Or:

Student Programmer Bill: "I'm writing my solution in one big module - it will save opening and closing all the files"

Student Programmer Jane: "The professor said we should use separate modules for similar functionality. I can't see that it makes much difference, but I guess we should do as he says"

This line of reasoning is itself fallacious - it's an AppealToTradition. For example, it might be that the local hospital is so crowded the emergency room takes 12 hours to treat anyone, in which time Grandpa will die. And it might be that sticking the solution in one big module leads Bill to do away with the filesystem as a program modularization mechanism, and use a soup or an inspector or a diagram to navigate from class to class.

What these folks could have argued logically was:

Mary: "That hospital is underfunded and understaffed, and Eb Johnson died in their waiting room last week. Let's tourniquet that bite and use the vinegar if Grandma feels sure about it, then try the hospital."

Jane: "I'm trying to remember the professor's argument. Oh yes, he said that sticking all the functions in one module would make it difficult to find individual ones and maintain them. Does that make sense to you? Maybe we can find another way to do it!"

Yes, *if* Mary and Jane knew a little something about the subject, they *could* have made these logical arguments. However, in situations where no one knows enough about the subject to make a logical argument, ArgumentFromAuthority is a reasonable HeuristicRule for choosing what to do. One hopes that, while doing that, one will gain enough experience to make a logical argument.


When refuting AdVerecundiam it is easy to fall into AdHominem.


AdVerecundiam works great if you reference just the right book author. If, however, you reference one that causes a negative emotional reaction in your target, then even if your case had merit you are screwed. --PhlIp


There's also a kind of argument from authority in reverse, as in "Oh, that must be false, because that's what <infamous expert> says!"

Yeah. "Positive thinking can't cure you, because that's just what UriGeller says!" I like it. Especially because it's not accurate. UG sez his positive thinking will cure you. --PhlIp


We apply our personal veracity tests on both quoted authority and presented logic. Of course experts know what they are talking about. It is just very difficult to pick the true expert. And true experts have a 'use by' date - just ask IsaacNewton.

The danger is when the listener has little knowledge of the subject, and her first encounters are all not as expert as she assumed. It is very difficult to change ideas which are accepted as expert. When I look back on the meaning of words used in InformationTechnology, and I remember what they meant early on, they are invariably reduced in meaning from the original. Two such words come to mind Relational and User Friendly, but there are many. I believe that both these changes can be attributed to the messages so strongly sent in the respective marketing wars which instigated them - one - Oracle, Informix and Ingres SQL battles, and - two - Microsoft's unprecedented Windows OS marketing campaign.

Now many 'experts' appear to believe in these distortions of marketing as scientific truth. I think that most people called 'expert', in any field, are those who are well-versed in ConventionalWisdom. -- PeterLynch

A while ago we hired an engineer to suggest a drainage solution for our house. I'm glad he was well-versed in ConventionalWisdom. -- JohnDuncan


The arguments that favor cases where the appeal results in a correct course miss the point: as mentioned previously, argumentum ad verecundiam means "appeal to reverence". It's not the authority on the subject being appealed to, it's the respect, and it effectively dares the opponent to denigrate the revered person. It's similar to an ad hominem argument, in fact, but in a "positive" manner. An argument cannot be logically made from the force of (relevant) authority, though it's certainly a respectable rhetorical device. Appeals to reverence alone, however, are considered weak (and fallacious) rhetorical devices. Consider, one deciding funding for community health clinics located in poor areas: one run by local government, or one run by the Missionaries of Charity. While either might have their strengths, one might face extreme backlash for passing up the latter -- who are you to snub Mother Theresa? (Possibly easier now that the less-than-stellar fiscal management of her order has come to be known).
The Latin means "appeal to reverence".

Is there any way to support that statement without an argument from authority?


If anyone has a paper certificate, such as a PhD or Microsoft Certification, you better believe them. And you better not ask questions. They are right, and that is that. True with many medical doctors who prescribe medicine within 10 minutes, without really informing you of any side affects. But also true with many programmers who just "know whats best" because of their magical intuition and certificate.

Watch out for people who always speak or write in a very clear and precise manner too, with no pondering about anything. If they rarely ask or hint questions, they already know everything. Short and precise sentences with never even a hint of run-on. They know they are just right. This is dangerous. Watch out for them


A friend of mine is currently in a debate wherein his oponent is falliciously appealing to authority. This friend has come to me for help in explaining the fallacy (since his oponent does not believe he is commiting a fallacy). Here is the dialogue:

Steve: Macroevolution is true, see this article on the Stickleback as proof. [Article gives examples of mircoevolution (change within a species) amongst the stickleback population. The author, an alleged expert on evolution, argues that this proves macroevolution (the creation of a new species).]

Brett: This article gives examples of microevolution, not macroevolution. Change within a species is, by definition, microevolution. Since this article only gives examples of microevolution, it does not prove macroevolution. Change within a species (microevolution) is a necessary condition for macroevolution (the creation of a new species) but in itself microevolution is not a sufficient condition for macroevolution. Macroevolution may or may not occur, but this article does not prove it to be so. Macroevolution does not necessarily follow from microevolution, it is a non-sequiter to suppose that it does. [Note: I am not necessarily agreeing that this argument is a non-sequitor, I am just repeating Brett's argument.]

Steve: You are too religiously blinded to admit the truth. No matter how many fallacies you invoke, the truth is, every single authority agrees that macroevolution is true and that articles such as this one prove it.

There are a lot of fallacies in Steve's final statement. First, rather than answer Brett's criticism about the stickleback article he avoides the question - he never responds to the claim that mircoe does not prove macroe. Second, there is some sort of ad hominem where he attacks Brett's religious beliefs rather than the argument. Third, not every authority agrees that marcroe is the case. There are many well though of scientists that are theists (or catastrophists), or believe in intelligent design that disagree regarding macroe. But the fallacy about which I am most concerned is what I perceive to be an appeal to authority that is fallicious. Steve states that "no matter how many fallacies you invoke...every single authority agrees that macroevolution is true..." seems to be arguing as follows:

If all authorities agree with a give theory, that theory is true. All authorities agree that macroe is true (and that articles such as this one prove it). Therefore macroe is true (and this aritlce proves it)

This is a fallacy. In debate and even rigorous logic one may appeal to authority. However, the work of that authority is thereby open to examination. If the work of the authority is called into question and found to be wanting, one cannot revert back to authority in general, he must argue against the argument presented.

Forgetting for a moment which side of the evolution debate you are on, could someone please comment. How can I help Steve understand he has committed a fallacy in the way in which he is appealing to authority.

Thank you.

We on this Wiki don't have many answers when it comes to making people see their own fallacies. Keep in mind, though, that Steve's opinion may be more along the line: "Experts - people who have, by nature, studied this subject far more than you or I - have largely come to an agreement that macro-evolution is true based on the available evidence. Scientific theories must be falsifiable by nature, so unless you have evidence to falsify this theory upon which experts largely agree, I seriously doubt you'll be able to sway anyone to your side - certainly not me." Steve doesn't care that he pointed you at the wrong paper - he probably didn't understand it anyway. Keep in mind that BurdenOfProof is, in a very practical and matter-of-fact way, to be shouldered by whomever is attempting to change what is 'accepted' truth in the audience. In this case, you're probably better off not arguing with Steve because he doesn't consider himself well enough educated in the subject to present all the proper arguments and evidence: he'll just wait for you to win against the community of experts.

Copied this nice statement to YouCantConvinceMe.

There's plenty of circumstancial evidence for macro-evolution, such as leg bones in whales and snakes. Thus, you don't have to rely on authorities. There's no other model I know of to explain these, except maybe the "sloppy creator" theory in which God uses mass copy-and-paste with low QC, which most religious folks do not accept. (I expect VB coder jokes to follow.)
Completely Useless?

Some argue that authoritative evidence is completely useless. As a practical matter, I disagree. It is indeed "weak" evidence, but not useless evidence. We often don't have time or access to reinvent the experience of others in ourselves. There's only so many shoes we can walk in and hats we can wear in a lifetime. An authority that has proved useful for other issues that we have verified is generally given more weight. In fact, there are music and movie recommendation algorithms that rely on this principle. The more another person's taste tends to match yours (based on review surveys of recommendations), the more weight their opinions are given. Of course, this is aesthetic-related metrics and not "facts", so may not be fully comparable to the issues that rage in software engineering. But then again, software engineering is largely related to psychology. -top

ItDepends on who the authority is. The catholic pope is an authority, and should be ignored. Ed Codd was an authority on relational, and he should be listened to.

[No, it doesn't depend on who the authority is. Stating the the pope's arguments should be ignored because he's the pope is an AdHominem, and stating that Ed Codd's arguments should be accepted because he's Ed Codd is an AdVerecundiam. Both are fallacies.]

See also: QuotingNotThinking, EvidenceVersusProof, EvidenceTotemPole, FallaciousArgument, RhetoricalTechnique,
CategoryJargon, CategoryCommunication, CategoryEvidence

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