A logical fallacy is a flaw in reasoning.
Strong arguments are based on testable premises and logical relationships, whilst weak arguments – whether due to weak premises or to weak relationships – tend to use logical fallacies to appear stronger than they are or to appear to weaken an opposing argument. Most people inadvertently commit logical fallacies in presenting an argument, but regrettably they are often deliberately used by politicians, the media, salespeople, and others to manipulate and fool people, and by those in power and authority to deflect, denigrate, or dismiss criticism.
It is important to recognize these fallacies so that one can avoid letting a debate be hijacked and insist that it return to the actual issue under discussion.
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Where two alternative states are presented as the only or exclusive possibilities, when in fact more possibilities exist, both possibilities may co-exist, and/or neither may be valid.» more »
Also known as the false choice or false dilemma, this insidious tactic has the appearance of forming a logical argument, but under closer scrutiny it becomes evident that there are more possibilities than the either/or choice that is presented. It may also be used to argue that because one thing (your opponent’s argument) is wrong something else (your argument) is correct, when there is no reason for that conclusion (your argument has to be proved on its own). At its worst, ie in politics/religion, the false choice is generally between supporting or submitting to a government program or revealing yourself as a traitor (‘us’ vs ‘them’, ‘with us or against us’). The evocation of an ‘enemy’ is related to Argumentum ad Populum and of course the Enemy Narrative.
Also: Perfect Solution, arguing against something simply because it is imperfect or incomplete rather than engaging with the terms at hand. This is the basis of the admonition, ‘Don’t let the perfect be the enemy of the good.’ Unfortunately, it is often invoked to dismiss criticism of a compromise rather than defend that compromise as indeed ‘good’.
Casting the argument in the mold of a hero-villain story.» more »
As described by George Marshall in his book Don’t Even Think About It, the Enemy Narrative is the basic structure of adventure tales and mythology: An enemy intends harm, and a hero intends to defeat the enemy and restore a good. Acting thus in the real world, creating enemies when the purpose of rhetoric is to persuade, avoids proper engagement with the problem and thwarts its solution. The Enemy Narrative combines elements of False Choice and Argumentum ad Populum and is typically an essential aspect of demagoguery. Already divisive and unconstructive, it invariably tends toward ‘scapegoating’, the singling out of someone or a group for blame (as in witch hunts, pogroms and other ‘cleansings’). In the religious or philosophical realm, such simplistic dualism of good versus evil is called manicheism.
Opposite: Win-Win. The fact that an ‘everybody benefits’ argument has to be made implies a social or economic situation in which that is in truth unlikely, that one side is winning a mess of pottage, the other a birthright.
Misrepresenting someone’s argument to make it easier to attack.» more »
By exaggerating, misrepresenting, or just completely fabricating someone's argument, it’s much easier to present your own position as being reasonable.
Reduction to Absurdity
Reductio ab Absurdum or Argumentum ab Absurdum.» more »
In classical rhetoric, this is an error of attempting to prove a statement by showing the impossible result if it were untrue (rather than clarifying the implied premise on which both conclusions are based). In popular argument, it is more like the Slippery Slope tactic, attempting to refute the validity of only an extreme or exaggerated version or imagined consequence of an argument instead of engaging with its substance. Note, however, that valid extrapolation of an argument’s reasoning may be used to show a weakness in its premises or relationships.
Asserting that if we allow A to happen, then Z will consequently happen too, therefore A should not happen.» more »
The problem with this reasoning is that it avoids engaging with the issue at hand, and instead shifts attention to baseless extreme, even exaggerated and implausible, hypotheticals. The merits of the original argument are then tainted by unsubstantiated conjecture.
Changing the Subject
Avoiding engagement with an argument by creating a new one.» more »
Also called ‘whataboutery’, this is the classic red herring or deflection tactic. In the form of ‘relativism’ it is used to make one’s own errors (or crimes) appear smaller by comparison with greater errors (or atrocities, calamities, etc) elsewhere. It is often used with the implication that harm in one form prevents more harm in another form, without, however, providing evidence for that comparison – see Doublethink.
≈ examples: ‘Don’t you care about …?’
Excluding the Middle, leaping from a premise to conclusion without a valid intervening connection.
Attacking your opponent’s character or personal traits, or simply name calling, in an attempt to thereby undermine or dismiss their argument.» more »
Besides directly denigrating the person, one may also accuse them of a hidden agenda or conflict of interest, either of which are indeed valid concerns but should not be used to avoid argument. A ‘vested interest’ is a specifically financial conflict of interest. Argumentum ad Hominem is an attempt to change the subject.
Judging something good or bad on the basis of where or whom it comes from.» more »
To appeal to prejudices surrounding something’s origin is another red herring fallacy. This fallacy has the same function as Argumentum ad Hominem, but applies instead to perceptions surrounding an argument’s source or context. It often relies on Argumentum ad Populum and even False Choice. Combined with Argumentum ad Hominem it is an attempt to exclude someone from a debate on the basis of irrelevant markers, such as formal schooling, language ability, command of specialized jargon, socio-economic status, social group, etc (ie exclusivism: ‘in’ group vs ‘out’ group; see also Appeal to Authority). At its ugliest, the Genetic Fallacy is racist and tribalist.
Appealing to popularity or the fact that many people do or believe something as an attempted form of validation.» more »
The flaw in these arguments is that the popularity or unpopularity of an idea has very little bearing on its validity.
Appeal to Emotion
Manipulating an emotional response in place of a valid or compelling argument.
Also: Argumentum ad Populum, appealing to group fears and prejudices, myths and ideals.» more »
Appeals to emotion include appeals to fear, envy, hatred, pity, guilt, idealism and more. Though a valid, and reasoned, argument may sometimes have an emotional aspect, one must be careful that emotion isn’t used to avoid rational argument. Argumentum ad Populum and Appeal to Emotion are perhaps the most dangerous of fallacies, used for a great range of purposes from selling soap to selling war. They define ‘demagoguery’.
Appeal to Authority
Saying that because an authority says something, it must therefore be true.» more »
It’s important to note that this fallacy should not be used to dismiss valid expert opinion. Invalid appeals are to inexpert authorities (government representative, parent, news commentator, vested interest, experts in another field, etc) to support your argument, rather than reference to valid evidence. A particularly nefarious form of Appeal to Authority is hiding behind ‘the law’ or excusing one’s argument/actions as ‘standard procedure’ (eg in the so-called ‘Nuremberg Defense’: ‘I was only following orders’). Rather than acknowledging the evidence that those laws, regulations, or industry standards are inadequate or ill enforced, or just plain bad, such argument seeks to dismiss that evidence – it is often combined with Isolated Incident (see Anecdote). Another form of Appeal to Authority combines Argumentum ad Hominen and Appeal to Technology to attack someone as, eg ‘against science’ to avoid engaging with their argument. It can also be combined with Argumentum ad Populum and Appeal to Emotion to appeal to the authority of a group (eg political party, lifestyle demographic), in which ‘exclusivism’ may come into play, ie the insidious assumption that different rules apply to different groups (‘double standard’), generally with the intention of dismissing scrutiny of one’s own group and/or authority. In the schoolyard this would be a form of ‘Peer Pressure’, asserting that if someone doesn’t agree with the argument, then they don’t belong in the group – see also Bandwagon and Appeal to Purity.
Appeal to Nature
Making the argument that because something is ‘natural’ it is therefore valid, justified, inevitable, good, or ideal.» more »
Many ‘natural’ things are considered to also be ‘good’, but naturalness itself doesn’t make something good or bad in a particular context.
Opposite: Appeal to Technology. Many ‘man-made’ things are indeed ‘good’, but novelty or technology itself doesn’t make something good or bad in a particular context. Also: Appeal to Progress.
Moving the goalposts, or asserting exception or new conditions when a claim is shown to be false.
No True Scotsman
Making an Appeal to Purity as a way to dismiss relevant criticisms or flaws of an argument.» more »
This fallacy is often employed as a measure of last resort when a point has been lost. Seeing that a criticism is valid, yet not wanting to admit it, new criteria are invoked to dissociate oneself or one’s argument.
≈ example: Angus declares that Scotsmen do not put sugar on their porridge, to which Lachlan points out that he is a Scotsman and puts sugar on his porridge. Taking offense, Angus asserts that no true Scotsman sugars his porridge.
Avoiding having to engage with criticism by turning it back on the accuser – answering criticism with criticism.» more »
Literally translating as ‘you too’ this fallacy is commonly employed as an effective red herring because it takes the heat off the accused having to defend themselves and shifts the focus back onto the accuser themselves. A variant may be called Preemptive Tu Quoque, accusing others of what you anticipate them to accuse you of, in the infantile belief that nobody will notice that you are in fact the one guilty of the charge, or that you are inoculating yourself from the charges by making them first. Preemptive Tu Quoque may also be called Conscious Projection, with the same intent.
≈ example: ‘I know you are but what am I?’
Assuming someone or something has the same characteristics as you and yours.» more »
Projection can also represent a failure of persuasive power.
Begging the Question
A circular argument, in which the conclusion is included in the premise.» more »
This logically incoherent argument often arises in situations where people have an assumption that is so ingrained, such as religious belief or cultural habit, that it is taken in their minds as a given, a premise that does not need to proved. It becomes ‘circular’ when the conclusion is essentially a restatement of that premise.
≈ example: God created the universe because only God could have done.
Asking a question that has an assumption built into it so that it can’t be answered without appearing guilty.» more »
Loaded question fallacies are particularly effective at derailing rational debates because of their inflammatory nature – the recipient of the loaded question is compelled to defend themselves and may appear flustered or on the back foot.
≈ example: When will my opponent apologize for taking bribes?
Dismissing a claim by accusing the person making it of being manipulated by or suggestible to the agendas of others.» more »
Nocebo comes to rhetoric from the field of medicine, where it refers to the opposite of placebo, that is, not a benefit due to positive suggestion (of eg a sucrose pill presented as a therapeutic drug) but rather a harm or, more usually, a lack of benefit due to negative expectation. It implies a ‘psychosomatic’ instead of a possible physical cause. In rhetoric it is essentially an attempt to ‘blame the victim’. It also implies an Enemy Narrative.
≈ example: Wendy started getting migraines after nearby wind turbines began operating. George, the company supervisor, said it was only because she had read of similar claims promoted by fossil fuel–funded websites and her doctor was only encouraging her belief.
Ignoring, dismissing, or wrongly interpreting, explaining, and recalling evidence to confirm or protect one’s beliefs and prejudices.» more »
Political opinion polls often use the tendency towards confirmation bias to shape their questions and manipulate answers.
Presuming that a real or perceived relationship between things means that one is the cause of the other.» more »
Many people confuse correlation (things happening together or in sequence) for causation (that one thing actually causes, or contributes to causing, the other to happen). Sometimes correlation is coincidental, or it may be attributable to a common cause.
Also: Weakest Link, dismissing a causative pathway by attacking the least supported part. This may or may not be valid, depending on the importance of that part and/or the strength of the evidence for the rest of the pathway implying that part.
Also: Complex Cause, dismissing a causative pathway by applying an accusation of False Causation to the relationship of its steps. Again, this may or may not be valid, depending on the evidence for their connection.
Also: Plausible Mechanism, dismissing an argument of causation by denying a plausible mechanism. Again, this may or may not be valid, depending on the evidence of causation. When correlation starts to look like causation, and can be tested, the lack of a known mechanism does not disprove it but rather points to a new field of research.
Cherry-picking data clusters to suit an argument, or finding a pattern to fit a presumption.» more »
This false cause fallacy is coined after a marksman shooting at barns and then painting a bullseye target around the spot where the most bullet holes appear. Clusters naturally appear by chance, and don’t necessarily indicate causation.
Burden of Proof
Saying that the burden of proof lies not with the person making the claim, but with someone else to disprove the claim.» more »
The burden of proof lies with someone who is making a claim, and is not upon anyone else to disprove. The inability, or disinclination, to disprove a claim does not make it valid. The Burden of Proof should not, however, be used to stifle reasonable inquiry and doubt.
Using personal experience or an isolated example instead of a valid argument, especially to dismiss statistics.» more »
Also: Isolated Incident, dismissing or downplaying the importance of an example as ‘rare’ or ‘insignificant’.
An anecdote may or may not represent the ‘norm’, and may or may not represent a rare exception to the ‘norm’. If research has not been compiled on the subject at issue, anecdote constitutes the raw data out of which statistical patterns may emerge and causal relationships discovered or proved.
Assuming that what’s true about one thing or a part of something is true about something similar or the whole.» more »
Analogies can be useful but they may also concentrate on irrelevant, inconsequential similarities and overlook pertinent, significant dissimilarities. We must show evidence for why there is a high degree of probability that a consistency exists.
≈ example: Daniel was brilliant at hide and go seek because he knew he was made up of atoms which are invisible to the naked eye and therefore so was he.
Saying that because one finds something difficult to understand, it’s therefore not true.» more »
Subjects such as biological evolution via the process of natural selection require a good amount of understanding before one is able to properly grasp them; this fallacy is usually used in place of that understanding.
Using double meanings, ambiguities of language, or equivocation, which weakens the conclusions or defies being pinned down.» more »
Politicians are often guilty of using ambiguity to mislead. It’s a particularly tricky and premeditated fallacy to commit. Also ‘wiggle room’ and ‘weasel words’. On scrutiny, such statements are seen to have no meaningful content.
Asserting that two conflicting ideas are the same.» more »
In George Orwell’s Nineteen Eighty-Four Doublethink, an aspect of ‘Newspeak’, acknowledges the cognitive dissonance between what the state says and what it does and simply asserts that they are the same. Although the logical error – and manipulative brutality – of Doublethink is obvious, it is disturbingly common in commercial, political, and moral life. Thus we have ‘good war’, ‘humane slaughter’, ‘sustainable consumerism’, and other oxymorons. It is generally a tactic of self-rationalization to avoid self-scrutiny that might lead to change.
To bring it into the realm of logic, Doublethink may be seen to derive from a logical progression cynically used to reject progress altogether. For instance, Freedom leads to inequality to disorder to tyranny to Slavery, therefore Freedom Is Slavery. And as Slavery is thus Freedom’s mature form, there is no reason to long for its immature form. In another example, Peace follows War follows Peace, and so on. Thus War Is Peace. And: To occupy a country is to liberate it.
Saying that a compromise, or middle point, between two extremes must be the truth.» more »
Some of the time the truth does indeed lie between two extreme views, or compromise is politically expedient, but this can bias our thinking: sometimes a thing is simply untrue and a compromise of it is also untrue. Halfway between a truth and a lie is neither and possibly an altogether new lie.
Believing that ‘runs’ occur (or don’t occur) to statistically independent phenomena such as roulette wheel spins.» more »
Each spin of the wheel is itself entirely independent from the last and hence carries the same odds.
Presuming a claim to be necessarily wrong because a fallacy has been committed in its the argument.» more »
This is just one more way to unconstructively avoid engaging with the actual matter of the argument, which it may well be possible to present without logical error.
[originally adapted from yourlogicalfallacyis.com]