Note 1:

The fallacy is common in political arguments, as illustrated in the first example.

Example 1:

My opponent is a conservative who voted against higher taxes and welfare, therefore he will also oppose gun control and abortion.

Although the four positions are often grouped together under the rubric of “conservative”, any given individual might hold one position but not another.

Note 2:

A package deal argument need not be a fallacy when the conclusion is stated as a likelihood rather than as a certainty. Amending example 1 as follows gives a valid argument:

The candidate is a conservative who voted against higher taxes, welfare, and gun control. Therefore, he is likely to oppose abortion as well.

Example 2:

A child molester was caught in a nearby neighborhood and he was friends with many of his neighbors. Therefore, that neighborhood is full of sex offenders.

The argument is a package deal fallacy because it assumes that the neighbors knew that their friend was a sex offender and also implies their endorsement of such activity. It assumes guilt by association under incidental circumstances.

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Note:

Misleading vividness is similar to the appeals to emotion that we will discuss in later episodes but with the difference that it acts in combination with hasty generalization, and it creates its effect by piling on details about the case. By contrast, an appeal to emotion need not involve hasty generalization and may be lacking in detail.

Example 1:

Anne: I am giving up extreme sports now that I have children. I think I will take up golf.

Bill: I wouldn’t do that. Do you remember Charles? He was playing golf when he got hit by a golf-cart. It broke his leg, and he fell over, giving himself a concussion. He was in hospital for a week and still walks with a limp. I would stick to paragliding!

Example 2:

Tom: I’m planning to go on vacation in Mexico.

Dick: Oh, I certainly wouldn’t go there. You know Tim? He visited Mexico and his trip was a disaster. He got robbed, beat up so badly that he was on crutches for two months, had to pay bribes everwhere he went and then caught this horrible disease called giardia.

Tom: I’d better not go there after all.

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An argument from analogy involves noting the shared properties of two or more things, and inferring that they also share some further property. The form of the argument is as follows:

        P and Q are similar with respect to properties a, b, and c.

        Object P has been observed to have further property x.

        Therefore, Q probably has property x also.

Several factors affect the strength of the argument from analogy:

        1. The relevance of the known similarities to the similarity inferred in the conclusion.

        2. The number and variety of the examples in the analogy.

        3. The number of characteristics shared by the things being compared.

An argument from analogy is weakened if it is inadequate in any of the above respects.

Example:

According to Steven Jay Gould (in his book, Leonardo’s Mountain of Clams & The Diet of Worms), Leonardo da Vinci attempted, but failed, to explain the evident upward movement of water within and on the Earth’s surface (how does rain and snow get into the sky, a spring on a mountain side, and so on) because his theory was that the behavior of the Earth was analogous to the functions of the human body (that is, that the human body was a microcosm of the Earth) and so the Earth’s water was analogous to the body’s blood. However, as Leonardo was evidently aware, for the analogy to be strong there must be a similar mechanism for moving the fluid up against its gravitational tendency to settle to the lower parts, for both the body and the Earth. At that time, various mechanisms had been proposed for this in the case of the blood (note that the theory that the heart circulated the blood was not proposed until a century later), none of which was plausible as an explanation for the upward movement of the Earth’s water. Leonardo never found a mechanism that explained both phenomena convincingly and it is now apparent that it was because his analogy is inadequate to the task. That is, it is a false analogy.

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The fallacy takes one of the following two alternative forms, where the person committing the fallacy is labelled “Tom”:

        Tom: No A are B.
        Dick: Here is an example of A that is B.
        Tom: Well, no true A are B.

        Tom: All A are B.
        Dick: Here is an example of A that is not B.
        Tom: Well, all true A are B.

Note 1:

The term was coined by philosopher Antony Flew in his 1975 book Thinking About Thinking. Here is the canonical example given in the book:

Imagine Hamish McDonald, a Scotsman, sitting down with his Glasgow Morning Herald and seeing an article about how the “Brighton Sex Maniac Strikes Again.” Hamish is shocked and declares that “No Scotsman would do such a thing.” The next day he sits down to read his Glasgow Morning Herald again and this time finds an article about an Aberdeen man whose brutal actions make the Brighton sex maniac seem almost gentlemanly. This fact shows that Hamish was wrong in his opinion but is he going to admit this? Not likely. This time he says, “No true Scotsman would do such a thing.”

Note 2:

The fallacy is similar to begging the question (episode 23) but with the difference that the conclusion is a modification of the subject of the initial claim so as to arbitrarily exclude a counterexample. Begging the question assumes the premise in the conclusion but does not modify it, and does not necessarily involve any counterexamples.

Note 3:

The fallacy is also similar to the overwhelming exception fallacy (discussed in the previous episode) insofar as both fallacies are committed in response to a counterexample but with the following difference: The overwhelming exception fallacy responds to the counterexample by acknowledging it by stating that the initial claim is “except for” the counterexample, and creating the false impression that the counterexample is insignificant. By contrast, the no true scotsman fallacy restates the initial claim in a way that fallaciously denies that the subject of the counterexample is a subject of the claim.

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Note:

A common way of committing the overhelming exception fallacy is to first make a hasty generalization and then, when confronted by the exceptions, to state that the generalization is “except for” those cases. Alternatively, the person making such an argument will anticipate the exceptions and exempt them before an opponent can point them out.

Example 1:

Our foreign policy has always helped other countries, except of course when it is against our National Interest.

Example 2:

All Americans are useless at foreign languages. Ok, I’ll make an exception for those who live in multi-ethnic neighborhoods, have parents who speak a foreign language, are naturally gifted in languages, have lived abroad or who went to a school with a good foreign language program, but the rest are absolutely useless at foreign languages.

Example 3:

Tom says: We are the freest country in the world!

Dick replies: What about the fact that we have the highest number of prisoners both as a proportion of the population and in absolute terms? Our total taxation as a proportion of GDP is greater than about two-thirds of the countries in the world. Self-medication is prohibited for many substances that can be bought over the counter in most countries. Getting in and out of the country and even flying from one part to another has turned into an invasive ordeal. There is a multitude of rules regarding starting a business and hiring and firing of employees; and street vending is banned. The national elections are a contest between stooges that end up implementing almost identical platforms. The government and the courts have subverted every last paragraph of the constitution, which is intended to protect our rights. The mass media present a conformity of lies. The primary and secondary education system consists largely of regimentation and indoctrination, and higher education is a usurous fraud of credentials that the typical young person will take decades to pay for and which will never gain him an appropriate job. Each of those things represents a significant limitation on our freedom, and on each score, many other countries do better.

Tom replies: Well, apart from those things, we are the freest country in the world!

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Note 1:

This fallacy is the opposite of slothful induction (discussed in the previous episode) which is the denial of the logical conclusion of an inductive argument.

Note 2:

The deductive version of this fallacy is the converse accident fallacy, discussed in episode 56.

Note 3:

When referring to a generalization made from a single example it has been called the fallacy of the lonely fact or the proof by example fallacy.

Example 1:

Tom travels through a town for the first time. He sees 10 people, all of them children. Tom concludes that there are no adult residents in the town.

Tom’s reasoning is a hasty generalization fallacy because 10 people is a very small sample of almost any town. Also, “there are no adult residents” is too strong a statement unless the sample includes the entire population because there would in fact only need to be one adult in order to invalidate it.

Example 2:

Dick sees a news report about “a big drugs bust” featuring a photo of police posing with hundreds of large, neatly stacked packs of what the caption says is some illegal drug. An official is quoted as saying, “we are winning the war on drugs!”

This is a fallacy of hasty generalization because it is a generalization about the total use of illegal drugs, based upon an unrepresentative event. If Dick gathered additional information, or the official was honest, then Dick might learn that illegal drugs have steadily dropped in price while their potency has steadily risen, which implies that their production and distribution system has become more efficient. He would also learn that only a small proportion is interdicted by law enforcement and that the officials, banks and politicians have too much financial incentive, in bribes, resales of seized product, money-laundering, increases in agency budgets, and excuses for more of a police state, to “win” the “war”, at least up until now.

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Note 1:

This fallacy is opposed to the fallacy of hasty generalization (to be discussed in the next episode) insofar as hasty generalization makes a generalization from unrepresentative or insufficient cases, while slothful induction is the failure to make a generalization justified by sufficient and representative cases.

Note 2:

The deductive version of this fallacy is the accident fallacy (also known as sweeping generalization), discussed in episode 55.

Example 1:

Hugo has had twelve accidents in the last six months, yet he insists that it is just a coincidence and not his fault.

The argument is a slothful induction because twelve accidents in six months is strong evidence of a common cause to the accidents that has to somehow involve Hugo, yet he claims that there is no common cause at all.

Example 2:

The polygamist has had twelve wives for twelve years but no children. Says he, “I just can’t imagine what is wrong with all those women!”

This is an example of slothful induction because children normally result from marriage and twelve wives for twelve years is sufficient to conclude that the absence of children has something to do with the man.

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Note 1:

This fallacy is opposed to the accident fallacy (discussed in the previous episode) insofar as the accident fallacy applies a generalization indiscriminately even to a clear exception, while the converse accident fallacy makes an exception to a generalization indiscriminately even for cases where the generalization should apply.

Note 2:

The inductive version of this fallacy is called hasty generalization (to be discussed in a later episode).

Note 3:

The slippery slope fallacy (to be discussed in a later episode) is the converse accident fallacy when used in the following context: namely, in an argument that claims that some insignificant event will result in a chain of events that produce an undesirable result, but without the arguer quantifying the likelihood of each step in the chain. The fallacy is in failing to support the argument by quantifying each step.

Example 1 (of converse accident):

If we allow people with glaucoma to use medical marijuana, then everyone should be allowed to use marijuana.

The argument is a converse accident fallacy because the medical exemption from the marijuana prohibition is applied to cases where the grounds for the exemption don’t apply. Notice that the argument is a fallacy regardless of one’s view of the prohibition. A person who argues against the prohibition needs to at least try to use relevant grounds, otherwise he is engaging in sophistry (the dishonest use of fallacies in debate).

Note 4:

By changing the wording, we get the slippery slope version of the above example, namely: “If we allow people with glaucoma to use medical marijuana, then eventually it will become acceptable to allow anyone to use marijuana.”

Example 2:

Because you allowed Jill, who was hit by a truck, to hand in her assignment late, you should allow the entire class to hand in their assignments late.

The argument is a converse accident fallacy because, as in example 1, the medical exemption from the general rule is applied to cases where the grounds for the exemption don’t apply.

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Note 1:

This is one of four fallacies of generalization that fit together as a family that I find useful for understanding and remembering. There also are other fallacies of generalization, that I hope to later orient in relation to these four. The four fallacies are the subject of this and the next three episodes. I’ve arranged them in the following grid with a one-sentence description of each. If you read more widely you may note that fallacyfiles.org uses the names “converse accident” and “hasty generalization” as synonyms for the same fallacy but here I follow Wikipedia’s definitions. The distinction of each fallacy from the other three has two (and only two) dimensions:

Note 2:

This fallacy requires that one confuse a generalization (“some”) for a categorical statement (“always and everywhere”). The potential for such confusion is reduced if one includes qualifying words such as “some”, “many”, “normally”, and “rarely” to indicate the generalization.

Example 1:

Cutting people with a knife is a crime.
Surgeons cut people with knives.
Therefore, surgeons are criminals.

This argument is an accident fallacy because it applies a useful generalization to a clear exception to the generalization.

Example 2:

Killing people is a crime.
Tom killed the armed burglar that threatened him in his home.
Therefore, Tom is a criminal.

This argument is an accident fallacy because it applies a useful generalization to a clear exception. Note that it requires a more challenging definition of crime than is needed in example 1. Everyone would be likely to agree that the argument in example 1 is a fallacy. However, the argument in example 2 would cause people who conflate “criminal” with “illegal” to consult their local legal code before they could decided on whether or not it was a fallacy. I claim that anyone who conflates the two terms is, as a result, going to commit logical contradictions in their own thinking – for example, when government agents do something, under color of law, that outrages them.

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Note:

Wikipedia’s discussion of this fallacy is confusing insofar as, after giving a definition similar to the one above, they then go on to introduce examples where cause and effect are unclear, rather than factually known. But cases where the cause is unclear are already described by cum hoc ergo propter hoc (which was the subject of episode 24) or post hoc ergo propter hoc (episode 47). Therefore in this discussion I shall adhere strictly to the definition above; that is, the cases where cause and effect are factually known but fallaciously reversed.

Example 1:

Europeans in the Middle Ages believed that lice were beneficial to your health, since there would rarely be any lice on sick people.

The reasoning was that the people got sick because the lice left. The real reason however is that lice are extremely sensitive to body temperature. A small increase of body temperature, such as in a fever, will make the lice look for another host. The medical thermometer had not yet been invented, so this increase in temperature was rarely noticed. Noticeable symptoms came later, giving the impression that the lice left before the person got sick.

Example 2:

Terrorism causes an increase in the power of the security agencies.

This is a wrong direction fallacy because the preponderance of evidence is that most apparent terrorism is covertly carried out by, or instigated by, security agencies. So the actual causal relationship is that it is the power of the security agencies that ultimately causes terrorism.

Example 3:

Narcotic drugs are illegal because of their harmful social effects.

This is a wrong direction fallacy because the harmful social effects of narcotic drugs are mostly caused by their illegality. In the typical case, a narcotic drug had less problems associated with it before it was made illegal as compared to after it was made illegal.

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