Logical Fallacies
Consider yourself rational, do you? đ
Here are 24 common thinking flaws (especially popular with politicians and even some journalists). How many do you regularly commit? This list comes from the good people at The School of Thought / Your Logical Fallacy Is. The only change is placing Anecdotal and Ad Hominem first. Also, minor editing and replacing whilst with while.
To discover more about thinking straight, read Hans Roslingâs landÂmark âFactfulnessâ.
Check out our Biases, Quotes, and Sources pages.
1. Anecdotal
You used a personal experience or an isolated example instead of a sound argument or compelling evidence.
Itâs often much easier for people to believe someoneâs testimony as opposed to understanding complex data and variation across a continuum. Quantitative scientific measures are almost always more accurate than personal perceptions and experiences, but our inclination is to believe that which is tangible to us, and/or the word of someone we trust over a more âabstractâ statistical reality.
Example: Michael said that that his grandfather smoked 30 cigarettes a day and lived till 97 â so therefore you shouldnât believe everything you read about meta analyses of methodologically sound studies showing proven causal relationÂships.
2. Ad Hominem
You attacked your opponentâs character or personal traits in an attempt to undermine their argument.
Ad hominem attacks can take the form of overtly attacking somebody, or more subtly casting doubt on their character or personal attributes as a way to discredit their argument. The result of an ad hominem attack can be to undermine someoneâs case without actually having to engage with it.
Example: After Jessica presents an eloquent and compelling case for a more equitable taxation system, Chris asks the audience whether we should believe anything from a woman who was once arrested and smells bad, too.
3. Strawman
You misrepresented someoneâs argument to make it easier to attack.
By exaggerating, misrepresenting, or just completely fabricating someoneâs argument, itâs much easier to present your own position as being reasonable, but this kind of dishonesty serves to undermine honest rational debate.
Example: After Matthew said that we should put more money into health and education, Joshua responded by saying that he was surprised that Matthew hates our country so much that he wants to leave it defenseless by cutting military spending.
4. Slippery Slope
You said that if we allow A to happen, then Z will eventually happen, too, therefore A should not happen.
The problem with this reasoning is that it avoids engaging with the issue at hand, and instead shifts attention to extreme hypotheticals. Because no proof is presented to show that such extreme hypotheticals will in fact occur, this fallacy has the form of an appeal to emotion fallacy by leveraging fear. In effect the argument at hand is unfairly tainted by unsubstantiated conjecture.
Example: Jacob asserts that if we allow same-sex couples to marry, then the next thing we know weâll be allowing people to marry their parents, their cars and even monkeys.
5. Appeal to Emotion
You attempted to manipulate an emotional response in place of a valid or compelling argument.
Appeals to emotion include appeals to fear, envy, hatred, pity, pride, and more. Itâs important to note that sometimes a logically coherent argument may inspire emotion or have an emotional aspect, but the problem and fallacy occurs when emotion is used instead of a logical argument, or to obscure the fact that no compelling rational reason exists for oneâs position. Everyone, bar sociopaths, is affected by emotion, and so appeals to emotion are a very common and effective argument tactic, but theyâre ultimately flawed, dishonest, and tend to make oneâs opponents justifiably emotional.
6. Loaded Question
You asked a question that had a presumption built into it so that it couldnât be answered without appearing guilty.
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.
7. Bandwagon
You appealed to popularity or the fact that many people do something as an attempted form of validation.
The flaw in this argument is that the popularity of an idea has absolutely no bearing on its validity. If it did, then the Earth would have made itself flat for most of history to accommodate this popular belief.
8. Genetic
You judged something as either good or bad on the basis of where it comes from, or from whom it came.
This fallacy avoids the argument by shifting focus onto somethingâs or someoneâs origins. Itâs similar to an ad hominem fallacy in that it leverages existing negative perceptions to make someoneâs argument look bad, without actually presenting a case for why the argument itself lacks merit.
9. Middle Ground
You claimed that a compromise, or middle point, between two extremes must be the truth.
Much of the time the truth does indeed lie between two extreme points, but this can bias our thinking: sometimes a thing is simply untrue and a compromise of it is also untrue. Half way between truth and a lie, is still a lie.
10. The Fallacy Fallacy
You presumed that because a claim has been poorly argued, or a fallacy has been made, that the claim itself must be wrong.
It is entirely possible to make a claim that is false yet argue with logical coherency for that claim, just as it is possible to make a claim that is true and justify it with various fallacies and poor arguments.
11. Special Pleading
You moved the goalposts or made up an exception when your claim was shown to be false.
Humans are funny creatures and have a foolish aversion to being wrong. Rather than appreciate the benefits of being able to change oneâs mind through better understanding, many will invent ways to cling to old beliefs. One of the most common ways that people do this is to post-rationalize a reason why what they thought to be true must remain to be true. Itâs usually very easy to find a reason to believe something that suits us, and it requires integrity and genuine honesty with oneself to examine oneâs own beliefs and motivations without falling into the trap of justifying our existing ways of seeing ourselves and the world around us.
12. Black-or-White
You presented two alternative states as the only possibilities, when in fact more possibilities exist.
Also known as the 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. Binary, black-or-white thinking doesnât allow for the many different variables, conditions, and contexts in which there would exist more than just the two possibilities put forth. It frames the argument misleadingly and obscures rational, honest debate.
13. The Texas Sharpshooter
You cherry-picked a data cluster to suit your argument, or found a pattern to fit a presumption.
This âfalse causeâ fallacy is coined after a marksman shooting randomly at barns and then painting bullseye targets around the spot where the most bullet holes appear, making it appear as if heâs a really good shot. Clusters naturally appear by chance, but donât necessarily indicate that there is a causal relationship.
14. Personal Incredulity
Because you found something difficult to understand, or are unaware of how it works, you made out like itâs probably not true.
Complex subjects like biological evolution through natural selection require some amount of understanding before one is able to make an informed judgement about the subject at hand; this fallacy is usually used in place of that understanding.
15. The Gamblerâs Fallacy
You said that ârunsâ occur to statistically independent phenomena such as roulette wheel spins.
This commonly believed fallacy can be said to have helped create an entire city in the desert of Nevada USA. Though the overall odds of a âbig runâ happening may be low, each spin of the wheel is itself entirely independent from the last. So while there may be a very small chance that heads will come up 20 times in a row if you flip a coin, the chances of heads coming up on each individual flip remain 50/50, and arenât influenced by what happened before.
16. No True Scotsman
You made what could be called an appeal to purity as a way to dismiss relevant criticisms or flaws of your argument.
In this form of faulty reasoning oneâs belief is rendered unfalsifiable because no matter how compelling the evidence is, one simply shifts the goalposts so that it wouldnât apply to a supposedly âtrueâ example. This kind of post-rationalization is a way of avoiding valid criticisms of oneâs argument.
17. Appeal to Nature
You argued that because something is ânaturalâ it is therefore valid, justified, inevitable, good or ideal.
Many ânaturalâ things are also considered âgoodâ, and this can bias our thinking; but naturalness itself doesnât make something good or bad. For instance murder could be seen as very natural, but that doesnât mean itâs good or justifiable.
18. Burden of Proof
You said that the burden of proof lies not with the person making the claim, but with someone else to disprove.
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 render that claim valid, nor give it any credence whatsoever. However it is important to note that we can never be certain of anything, and so we must assign value to any claim based on the available evidence, and to dismiss something on the basis that it hasnât been proven beyond all doubt is also fallacious reasoning.
19. Appeal to Authority
You said that because an authority thinks something, it must therefore be true.
Itâs important to note that this fallacy should not be used to dismiss the claims of experts, or scientific consensus. Appeals to authority are not valid arguments, but nor is it reasonable to disregard the claims of experts who have a demonstrated depth of knowledge unless one has a similar level of understanding and/or access to empirical evidence. However, it is entirely possible that the opinion of a person or institution of authority is wrong; therefore the authority that such a person or institution holds does not have any intrinsic bearing upon whether their claims are true or not.
20. False Cause
You presumed that a real or perceived relationship between things means that one is the cause of the other.
Many people confuse correlation (things happening together or in sequence) for causation (that one thing actually causes the other to happen). Sometimes correlation is coincidental, or it may be attributable to a common cause.
21. Tu Quoque
You avoided having to engage with criticism by turning it back on the accuser â you answered criticism with criticism.
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22. Ambiguity
You used a double meaning or ambiguity of language to mislead or misrepresent the truth.
Politicians are often guilty of using ambiguity to mislead and will later point to how they were technically not outright lying if they come under scrutiny. The reason that it qualifies as a fallacy is that it is intrinsically misleading.
23. Composition/Division
You assumed that one part of something has to be applied to all, or other, parts of it; or that the whole must apply to its parts.
Often when something is true for the part it does also apply to the whole, or vice versa, but the crucial difference is whether there exists good evidence to show that this is the case. Because we observe consistencies in things, our thinking can become biased so that we presume consistency to exist where it does not.
24. Begging the Question
You presented a circular argument in which the conclusion was included in the premise.
This logically incoherent argument often arises in situations where people have an assumption that is very ingrained, and therefore taken in their minds as a given. Circular reasoning is bad mostly because itâs not very good.