Category Archives: Logical fallacies

‘It’s only a theory’

by Tim Harding

(An edited version of this article was published in The Skeptic magazine,
June 2018, Vol 38 No 2)

One of the most face-palming things about having a science background is when creationists or other science deniers say ‘It’s only a theory’ when dismissing a scientific theory such as evolution.  This was recently the misconception that frustrated readers the most on The New York Times – Science Facebook page.

In everyday conversation, we tend to use the word ‘theory’ to mean a hunch, a guess or tentative hypothesis, as opposed to a known fact.  But that’s not what a ‘theory’ means to scientists.

‘In science, the word theory isn’t applied lightly,’ says Kenneth R. Miller, a cell biologist at Brown University. ‘It doesn’t mean a hunch or a guess. A theory is a system of explanations that ties together a whole bunch of facts. It not only explains those facts, but predicts what you ought to find from other observations and experiments.’

Photo credit: Zohar Lazar

The word ‘proof’ is used in mathematics but not in serious science.  I don’t recall ever seeing the word ‘proof’ used in this sense in a published scientific paper.

The prevailing scientific theory is the one that best explains the facts and has not been falsified, despite experimental attempts to do so. As Richard Dawkins says ‘Gravity is a fact. Evolution is a fact. The prevailing theory of gravity is Einstein’s. The prevailing theory of evolution is Darwin’s.’  Dawkins has also invited anyone who doubts the theory of gravity to test it by jumping out of a tenth-storey window.

This conflation of two different meanings of the word ‘theory’ is an instance of the equivocation fallacy.  In logic, equivocation is an informal fallacy resulting from the use of a particular word or expression in more than one sense throughout an argument, leading to a misconception.  It is a type of ambiguity that stems from a term having two distinct meanings, not from the grammar or structure of the sentence.

Reference:

Zimmer, Carl. In Science, It’s Never ‘Just a Theory’. The New York TimesApril 8, 2016.

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Cultural universals vs cultural relativism

cultural universal (also called a human universal), as discussed by Emile DurkheimGeorge MurdockClaude Lévi-StraussDonald Brown,  Steven Pinker and others, is an element, pattern, trait, or institution that is common to all human cultures worldwide. In his book Human Universals (1991), Donald Brown defines human universals as comprising “those features of culture, society, language, behavior, and psyche for which there are no known exception”, providing a list of hundreds of items he suggests as universal. Steven Pinker lists all Brown’s universals in the appendix of his book The Blank Slate.

Evolutionary psychologists hold that behaviors or traits that occur universally in all cultures are good candidates for evolutionary adaptations. Some anthropological and sociological theorists that take a cultural relativist perspective may deny the existence of cultural universals: the extent to which these universals are “cultural” in the narrow sense, or in fact biologically inherited behavior is an issue of “nature versus nurture“. The existence of cultural universals provides strong evidence against the currently fashionable notion that all human behaviours, including gender differences, are culturally determined.

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Consent to risk fallacy

A common argument against counter-terrorism measures is that more people are killed each year by road accidents than by terrorists.  Whilst this statistic may be true, it is a false analogy and a red herring argument against counter-terrorism. It also ignores the fact that counter-terrorism deters and prevents more terrorist attacks than those that are eventually carried out.

This fallacious argument can be generalised as follows: ‘More people are killed by (fill-in-the-blank) than by terrorists, so why should we worry about terrorism?’  In recent media debates, the ‘blank’ has included not only road accidents, but also deaths from falling fridges and bathtub drownings.  However, for current purposes let us assume that more people do die from road accidents than would have died from either prevented or successful terrorist attacks.

Whenever we travel in a car, almost everybody is aware that there is a small but finite risk of being injured or killed.  Yet this risk does not keep us away from cars.  We intuitively make an informal risk assessment that the level of this risk is acceptable in the circumstances.  In other words, we consent to take the risk of travelling in cars, because we decide that the low level of risk of an accident does not outweigh the benefits of car transport.

On the other hand, in western countries we do not consent to take the risk of being murdered by terrorists, unless we deliberately decide to visit a terrorist-prone area like Syria, northern Iraq or the southern Philippines.  A terrorist attack could occur anywhere in the West, so unlike the road accident analogy, there is no real choice a citizen can make to consent or not consent to the risk of a terrorist attack.

The Consent to risk fallacy omits this critical factor of choice from the equation, so the analogy between terrorism and road accidents is false.

 

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Travel expenses are not ‘entitlements’

‘I hate the word entitlement’
– Prime Minister Malcolm Turnbull, 13 January 2017

During the recent political scandal about MPs claiming reimbursement for non-work related travel expenses, the media has mistakenly referred to travel expenses as ‘entitlements’, thus implying that they are some sort of ‘perk‘* of office.  This usage of the word ‘entitlement’ is irrational; and any argument that the reimbursement of legitimate work-related travel expenses is a perk is fallacious. It reveals a lexicological laziness on the part of journalists who pride themselves on being wordsmiths.

All employees have the right to be reimbursed for legitimate expenses incurred as a result of doing their job. Such reimbursements are not classified as income by the ATO, and they cannot logically be regarded as a ‘perk’ of office. On the contrary, if legitimate work expenses were not reimbursed, the employee would in effect be donating money to their employer.

Where such expenses are claimed for non-work related activities, they should not be reimbursed and if they have been reimbursed in error, they need to be repaid by the recipient. In this context, the use of the word ‘entitlement’ is doubly irrational.

Note:

*Cambridge Dictionary definition: An advantage or something extra, such as money or goods, that you are given because of your job e.g. ‘A company car and a mobile phone are some of the perks that come with the job’.

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Appeal to hypocrisy

Appeal to hypocrisy (also known as Tu quoque, Latin for, ‘you also’) is an informal logical fallacy that tries to discredit the validity of the opponent’s argument by asserting the opponent’s failure to act consistently in accordance with its conclusion(s).

The Appeal to Hypocrisy fallacy follows the pattern:

  1. Person A makes claim X.
  2. Person B asserts that A’s actions or past claims are inconsistent with the truth of claim X.
  3. Conclusion: Therefore X is false.

An example would be

Peter: ‘Based on the arguments I have presented, it is evident that it is morally wrong to use animals for food or clothing.’

Bill: ‘But you are wearing a leather jacket and you have a roast beef sandwich in your hand! How can you say that using animals for food and clothing is wrong?’

This argument is a fallacy because the moral character or past actions of the opponent are generally irrelevant to the validity of the argument. It is often used as a red herring tactic and is a special case of the ad hominem fallacy, which is a category of fallacies in which a claim or argument is rejected on the basis of facts about the person presenting or supporting the claim or argument.

 

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No true Scotsman

No true Scotsman is a kind of informal fallacy in which one attempts to rescue a universal generalisation from counterexamples by changing the definition in an ad hoc fashion to exclude the counterexample. Rather than denying the counterexample or rejecting the original claim, this fallacy modifies the subject of the assertion to exclude the specific case or others like it by rhetoric i.e. those who perform that action are not part of our group and thus criticism of that action is not criticism of the group.

Philosophy professor Bradley Dowden explains the fallacy as an ‘ad hoc rescue’ of a refuted generalisation attempt. The following is a simplified rendition of the fallacy:

Person A: ‘No Scotsman puts sugar on his porridge.’

Person B: ‘But my uncle Angus likes sugar with his porridge.’

Person A: ‘Ah yes, but no true Scotsman puts sugar on his porridge.’

The introduction of the term is attributed to British philosopher Prof. Antony Flew, because the term originally appeared in Flew’s 1971 book An Introduction to Western Philosophy.

A practical example of this fallacy occurs when Marxists try to defend their regressive and unworkable ideology against the overwhelming evidence from the 20th century that almost every communist regime was brutally repressive; and most of them resulted in poverty for everybody except the communist party hierarchy. ‘But they weren’t true communists’ they say. Yeah, right.

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‘I’m entitled to my opinion’

(An edited version of this article was published in
“The Skeptic” Vol 37, No. 2, June 2017)

The claim ‘I’m entitled to my opinion’ or ‘I have a right to my opinion’ is a logical fallacy in which a person rejects objections to their argument by claiming that they are entitled to their opinion.  This claim is usually uttered by people in disagreement when they have hit the wall in defending their point on its merits. It is a last ditch rhetorical device that attempts to rescue their position by defending their right to hold an opinion, no matter how stupid, ignorant or ill-founded that opinion might be.

The claim exemplifies a red herring. The right to have an opinion is not what is in dispute. Whether one has a particular entitlement or right is irrelevant to whether one’s opinion is true or false. To assert the existence of the right is a failure to provide any justification for the content of the opinion. The claim also implies that all opinions are equal, which exemplifies the relativist fallacy.[1]

The entitlement would be relevant only if it guaranteed the truth of your opinions. But it can’t do that, because it is an entitlement supposedly enjoyed by everybody. And people disagree.  Two debaters are both entitled to their contradictory opinions about a given issue, but they can’t both be right. [2] So insisting that you are entitled to your opinion cannot possibly give you any logical advantage in a debate.

Endnotes

[1] The relativist fallacy, also known as the subjectivist fallacy, is claiming that something is true for one person but not true for someone else. The fallacy rests on the law of noncontradiction. The fallacy applies only to objective facts, or what are alleged to be objective facts, rather than to personal tastes or subjective experiences.

[2] In classical logic, the law of non-contradiction (LNC) is the second of the three classic laws of thought. It states that contradictory statements cannot both be true in the same sense at the same time, e.g. the two propositions ‘A is B’ and ‘A is not B’ are mutually exclusive.

References

Harding, Tim ‘Who needs to Know?’ The Skeptic magazine, September 2015, Vol 36 No 3 p.36.

Stokes, Patrick., ‘No, you’re not entitled to your opinion’. The Conversation. October 5, 2012.

Whyte, Jamie (August 9, 2004). ‘Sorry, but you are not entitled to your opinion’. The Times. News UK.

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There are no ‘judicial inquiries’

The popular Australian media often refers to calls for a ‘judicial inquiry’.  There is actually no such thing in Australia (or Canada) – this term is incorrect and quite misleading.

Whilst Royal Commissions and other boards of inquiry are sometimes (but not necessarily) chaired by retired or sitting judges, they are not acting in their capacity as judges when conducting a public inquiry. Thus these inquiries are not part of the judicial system – they are appointed by and are part of the executive branch of government. They do not ‘sit in judgement’ – all they can do is to make recommendations to government.

Associate Chief Justice Dennis R. O’Connor of Ontario, Canada has put it this way:

‘There is some debate as to whether sitting judges should serve as commissioners of independent inquiries.  Conducting an inquiry is not part of the judicial role nor involves judicial duties.  The creation of an inquiry is an act of the executive.  A judge who serves as a commissioner is carrying out a function of the executive, not the judicial branch of government.  The judge as commissioner does not adjudicate on issues of civil or criminal liability.  The findings and recommendations in a report have no binding legal effect.  The judge fulfills the function frequently carried out by non-judicial investigators or committees.'[1]

The Australian High Court has cited the opinion of the Supreme Court of the United States in Mistretta v United States [2] :

 

‘The legitimacy of the Judicial Branch ultimately depends upon its reputation for impartiality and nonpartisanship.  That reputation may not be borrowed by the political Branches to cloak their work in the neutral colors of judicial action.’

The former Chief Justice of Australia, Murray Gleeson has commented:

‘That is a salutary warning even in jurisdictions where there is no constitutionally required separation of powers, such as the Australian States.  There are well understood practical dangers of judges being drawn into political controversy by an injudicious decision to take on an inquiry in which partisan interests are involved.  It may be that the reason why the executive seeks a judge for an inquiry is that it is obvious that it may arouse political passions, and it is hoped they may be cooled by a neutral inquirer.  That might be a good reason for the judiciary to decline to be drawn in.  What is worse, however, is a case where an inquiry is given a task which is of such a nature that its performance cannot be completely independent of executive or legislative influence.  It is one thing to seek to turn the judiciary’s reputation for impartiality to public advantage; it is another thing to use that reputation to give to partisan executive or legislative action a spurious appearance of impartiality.'[3]

In 1923, Chief Justice Irvine wrote to the Victorian Attorney-General declining a request that he invite one of the judges of the Supreme Court of Victoria to undertake a Royal Commission, and expressing the view that it was generally inappropriate for judges to do other than hear and determine issues of fact and law in the context of the resolution of a justiciable matter.  In 1954, the judges of the Supreme Court of Victoria, with the support of the Victorian Bar, adopted a resolution that, except in a matter of national importance arising in times of national emergency, it is undesirable that any judge should accept nomination as a Royal Commissioner.  The Chief Justice of Victoria has told former Chief Justice Gleeson that this remains the view of her Court.[3]

References

[1] The Hon. Associate Chief Justice Dennis R. O’Connor  ‘Some Observations on Public Inquiries’, Canadian Institute for the Administration of Justice, Annual Conference. October 10, 2007, Halifax, Nova Scotia.

[2] US Supreme Court Decision. Mistretta v United States 488 US 361 at 407 (1989).

[3]  Murray Gleeson, ‘The Right to an Independent Judiciary’ Speech to 14th Commonwealth Law Conference, London, September 2005.

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Conjunction Fallacy

One of the central assumptions of mainstream economics has been that people make rational choices.  As a challenge to this assumption, Nobel prize winning behavioural economist Prof. Daniel Kahneman gives an example where some Americans were offered a choice of insurance against their own death in a terrorist attack while on a trip to Europe, or insurance that would cover death of any kind on the trip. People were willing to pay more for the former insurance, even though ‘death of any kind’ includes ‘death in a terrorist attack’.

This is an instance of the Conjunction Fallacy, which is based on the false assumption that specific conditions are more probable than general ones.  This fallacy usually stems from thinking the choices are alternatives, rather than members of the same set.

The logical form of this fallacy is:

Premise: X is a subset of Y.

Conclusion: Therefore, X is more probable than Y.

The probability of a conjunction is never greater than the probability of its conjuncts. In other words, the probability of two things being true can never be greater than the probability of one of them being true, since in order for both to be true, each must be true. However, when people are asked to compare the probabilities of a conjunction and one of its conjuncts, they sometimes judge that the conjunction is more likely than one of its conjuncts. This seems to happen when the conjunction suggests a scenario that is more easily imagined than the conjunct alone.

Interestingly, Kahneman discovered in earlier experiments that statistical sophistication made little difference in the rates at which people committed the conjunction fallacy. This suggests that it is not enough to teach probability theory alone, but that people need to learn directly about the conjunction fallacy in order to counteract the strong psychological effect of imaginability.

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The Recommendation Fallacy

By Tim Harding

(An edited version of this fallacy was published in The Skeptic magazine Vol.37, No.1, March 2017 ).

I was once elected as a local government councilor in an inner Melbourne suburb.  The Council had serious concerns about poor staff performance, both in providing advice to Council and in implementing Council decisions.  As these problems appeared to be systemic rather than just the fault of the CEO, we brought in management consultants for an independent review of the Council administration.

After interviewing both Councillors and staff, the management consultants reported that there were indeed systemic organisational deficiencies related to poor staff culture.  One of the most pervasive problems was that few staff understood the difference between a recommendation and a decision.  They seemed to think that staff made decisions and the Council either ‘ratified’ or ‘overturned’ their ‘decisions’.  Some staff even mistakenly classified rejection of their recommendations by the elected Councillors as ‘political interference’! They did not seem to understand that their role was to provide professional advice to the Council, including options and recommendations. (There were also deficiencies in the implementation of Council decisions, but that is a separate issue).

I also found that this was a problem at junior levels in the state public service; but not in the middle and senior ranks. Junior staff needed to be taught how to analyse problems and make recommendations, instead of indulging in what I called ‘problem referral’ without providing options or recommendations to management.  I have also found this staff deficiency in some NGOs, such as ANTaR, where I have been a board member.  It seemed to me that our education system did not teach students these fairly fundamental skills of working in a professional office environment.

A recommendation has no status other than as advice to a decision-maker.  Although a recommendation may well be persuasive, depending upon the expertise of its author, there is no obligation by a decision-maker to adopt any recommendation.  Thus it makes no sense to say that a recommendation has been ‘overturned’.  Only decisions can be overturned.  Similarly, a recommendation cannot be ‘implemented’ unless and until it has been adopted as a decision by decision-maker who is authorised to make that decision. (The media often make these errors). These are errors of reasoning, just like other fallacies.  So I have dubbed such confusions between recommendations and decisions instances of the Recommendation Fallacy.

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