Sonus silentii fallacy

34 点作者 pud超过 11 年前

15 条评论

itafroma超过 11 年前

The fallacy the author is thinking of is called argumentum e silentio, or the argument from silence. Academically, arguments of the form "well, X civilization is known for meticulous record-keeping and they make no mention of Y, therefore Y must not have happened" would be good examples of arguments from silence.In this instance however, it'd be of the form, "if our product was defective, our customers would speak up. We haven't heard anything from our customers about it, therefore our product is not defective."The author correctly points out that this formally follows the modus tollens format:<pre><code> A: Our products are defective B: Customers are complaining to us P1. A → B P2. ~B ------ C: ~A </code></pre> This is a valid[1] argument: assuming the premises P1 and P2 are true, C necessarily follows. The fault in logic comes from P1 not being true: it is not necessarily the case that customers would complain to the company if the product was defective. Since P1 is false, the argument is unsound[2] and thus ~A (our products are not defective) is not necessarily true.However, it's important to point out that one can still inductively[3] conclude ~A is likely to be true, just not necessarily true. That is:<pre><code> P1. Based on past evidence, our products being defective likely means customers would speak up about it. P2. Our customers haven't complained to us ----- C: Our products are probably not defective. </code></pre> This is a perfectly fine inductive argument. The company, should they be claiming to make this argument, would have to be amenable to be proven wrong: while it may be unlikely that customers would remain silent if their product was defective, it's certainly possible.[1]: <a href="https://en.wikipedia.org/wiki/Validity" rel="nofollow">https://en.wikipedia.org/wiki/Validity</a>[2]: <a href="https://en.wikipedia.org/wiki/Soundness" rel="nofollow">https://en.wikipedia.org/wiki/Soundness</a>[3]: <a href="https://en.wikipedia.org/wiki/Inductive_reasoning" rel="nofollow">https://en.wikipedia.org/wiki/Inductive_reasoning</a>

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jloughry超过 11 年前

In the second World War, bombers returning from missions over Germany were carefully examined for battle damage and the locations of bullet holes mapped. Armour plating is heavy and cuts into the planes' useful range and load---where should it be placed? Abraham Wald suggested putting armour plate over places where no bullet hole had ever been observed, because those were the vulnerable spots. Planes shot in those locations never returned to be counted.It's called the problem of non-ignorable non-response.

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wrs超过 11 年前

I worked on the first Microsoft product to ship with the "sorry, the program has crashed, please report it" dialog box. (MSN Explorer, if you're curious.) Very soon I had thousands of reports of crashes in a system service that were clearly not the fault of our app. I took the reports to the other team to get the problem fixed, and their initial response was "no users have reported it, and it's never happened in our test lab, so we'll make it a low-priority bug". (!!!)Thank goodness for the internet...your app/device can report its own problems rather than waiting for your users to do it.(BTW: MS product teams did quickly regroup to prioritize actual crash reports over the test lab.)

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StavrosK超过 11 年前

Absence of evidence is evidence of absence (it's not proof of absence). If there is no evidence that anyone is unhappy with the product, it is strictly better than if there is evidence that some people are unhappy (obviously). So, the "evidence of absence" one isn't a fallacy, really.Hell, the modus tollens is a valid argument form. If X, then Y. No Y, therefore no X (but this isn't strictly "evidence of absence").

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erehweb超过 11 年前

Going from "nobody has complained" to "the customers are happy" does not seem too much of a stretch, particularly for an expensive unit. Granted, it doesn't logically follow, but I would class this as a reasonable deduction from evidence rather than a fallacy. Note also that it's self-correcting - once one person complains, the company can't use that defense any more.

codex超过 11 年前

Unfortunately one cannot assume the opposite either: that just because your unit broke, others have broken, or many others have broken. You buy thousands of things in your lifetime; odds are that at least one will suffer some kind of freak failure, or even repeated failures.In this case the manufacturer is in a position to have more evidence, at least in principle, even if they might be inclined to ignore it.In my own experience, if Google didn't turn up other instances of my problem, the issue was extremely rare or caused by some unique quirk in my environment.

noonespecial超过 11 年前

I own a relatively expensive piece of electronic equipment that keeps breaking.I corresponded with someone who works for the manufacturer. His response to me was (paraphrased), “we’ve sold thousands of these units and nobody else has complained. Therefore, our product must be good.”I've never quite understood the logic behind this thinking on the part of product manufacturers. The product has already disappointed the customer on multiple occasions, but the customer is still willing to give the product another chance in the form of a repair or replacement; and the manufacturers first impulse is that rotten customer is stealing from us, treat him like some kind of thief.They're about to lose that customer (and everyone he knows who asks him for a recommendation) forever. Send him a replacement. Send two. For bonus points, pay for him to ship the defective one back for detailed analysis of what was going wrong.

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pjdorrell超过 11 年前

A variation on this is:* Our Internal Revenue Collection website must be really good, because no one ever complains about it, even though we have a conspicuous link to the complaints form on every page.* Why would anyone ever hesitate to make a complaint to the Ministry of Internal Revenue Collection if they felt they had something to say?

greenyoda超过 11 年前

It's also possible (and perhaps more likely) that all the other customers received products that work OK, but there was some kind of rare manufacturing defect in the device the author bought (e.g., an out-of-tolerance part or a bad trace on a circuit board). Of course, the manufacturer should have recognized that as a possibility. This kind of problem shows up a lot with cars, where you can have a "lemon" that has recurring problems.

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prof_hobart超过 11 年前

Is it the same unit that keeps breaking, or do they keep sending replacements and they all keep breaking?If it's the former, then the story seems to miss the rather critical point that even if they were 100% certain that every other user was happy, that's irrelevant to whether he's got a faulty unit.However good your quality control is, eventually a faulty one is going to fall through the net, so the fact that a thousand or a million other people have ones that didn't go wrong does't help the one person who's unit did.Of course, if he claims to have had multiple faulty units, and no one else has ever reported any, that's a different matter.

mathattack超过 11 年前

This seems to me to be more like Supportus Lazicus. Many support organizations are purposefully understaffed, so you have to mathematically prove that there's a problem to get through the noise. For small ticket items it's very hard to beat this. Many large ticket software firms have this problem too. That's why you need to negotiate an out in the contract, so you can call the salesman and say, "Your competitor is coming in for a demo in forty five minutes. I'm not sure if this is a bug or not, can you look into it for me?" You'll get a response within 30 mins.

gcb1超过 11 年前

"but 100% of the access are using IE6. why should we add support for another browser?"

kineticfocus超过 11 年前

A Priori rationalization based on Argumentum ad Ignorantiam. Conflated with A Fortiori of the evidence. (Just my guess)edit: could also be labeled a non sequitur.

fluxon超过 11 年前

"I own a relatively expensive piece of electronic equipment that keeps breaking."Underconstrained problem set: no $ figure, class of product, mfg name, or indication of who repaired it. Without any specifics, it's difficult to analyze the manufacturer's response in its true context.

cstrat超过 11 年前

Reading the title I attributed the faulty electronics as being a Sonos product.

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