This article first tells the story of someone who became paranoid with worry about things he later realised were unlikely to be really happening. He had justified his beliefs in them in ways he later realised weren't logical at all, arguing heatedly with parents and others who tried to convince him he was wrong. When he started thinking more clearly, after someone had pointed out to him the mistakes in reasoning he was making, he felt reassured, after he got over the embarrassment of having believed such unlikely things for so long.
The article then discusses lots of different ways people can make mistakes in their thinking or deliberately try to mislead people, giving examples of how it can be done, and talking about how to recognise those things as mistakes or attempts to mislead.
Skip past the following quotes if you'd like to get straight down to reading the article.
No matter where you go or what you do, you live your entire life within the confines of your head.
You and I are not what we eat; we are what we think.
--Walter Anderson, The Confidence Course, 1997
Did you ever stop to think, and forget to start again?
--Winnie the Pooh
People demand freedom of speech as a compensation for the freedom of thought which they seldom use.
Too often we... enjoy the comfort of opinion without the discomfort of thought.
--John F. Kennedy
The trouble with most people is that they think with their hopes or fears or wishes rather than with their minds.
I must have a prodigious quantity of mind; it takes me as much as a week sometimes to make it up.
--Mark Twain, The Innocents Abroad
A man posted to an Internet forum, telling the story of how not too long before, he'd started believing some paranoid conspiracy theories. He became obsessed with finding out more and more information about them. Thinking he was going to the place where he could get the most reliable information about them, he went to the website of a leading spreader of paranoid conspiracy theories. He didn't think to find out information from people who said there was nothing in the conspiracy theories, because he considered them untrustworthy. The leading spreader of them became his hero, the one who was exposing things the government and other organisations wanted to keep hidden, asking questions no one else was.
His family and friends began to find it unpleasant to be around him, because he would accuse them of being brainwashed sheep following the establishment unquestioningly, and he'd try to convince them there are evil organisations bent on controlling the minds of the public to keep them towing the line.
He said his mother tried especially hard to debunk his views, sending him emails explaining the other side. He wouldn't listen; he would respond by sending her YouTube links to things that backed up his opinions and by repeating the conspiracy theories he believed, as if she'd never heard them before. He regretted it later, but at the time, he rejected what she was saying because he dismissed her as just a biased government loyalist who would be bound to think the way she did because she was a Christian, as George Bush claimed to be, who was in power then. He now realises it was illogical to reject all the advice she was giving him just because of something personal about her.
His mother wasn't the only one who tried to reason with him; several people did. But it just made him angry and gave him more motivation to do whatever he could to find more evidence to back up his case. He became dedicated to finding out more and more to support his views. He would reject girls because of their political beliefs, and nearly split up with the girlfriend he had at the time he wrote the message on the forum because they argued about his conspiracy beliefs.
He says he's embarrassed about the views he held now, because he'd done a philosophy degree where he'd done classes in logic, so he ought to have seen the flaws in them. But it wasn't till someone pointed out to him what shaky ground he was basing his arguments on that he did. A friend of his came for a visit. At first the friend thought he was joking around when he talked about all the paranoid conspiracy theories he believed in. But when he convinced his friend he was serious and bombarded him with what he was convinced was absolutely unshakeable evidence, his friend laughed, and then pointed out all the logical flaws in the way he'd been dealing with the evidence for and against them, for instance rejecting his mother's claims and advice not because he could prove there was something wrong with them but because of something that didn't really have anything to do with whether the claims were true or not, the fact he assumed she must be a Bush loyalist. His friend showed him that all of his arguments had something wrong with the logic behind them. It made him realise that for years, rather than trying to find the best evidence whatever conclusion it led him to, he'd started out with a conclusion and then tried his best to find evidence that supported it.
He almost cried when he realised that was true. He'd thought he could pride himself on being a skeptical, critical thinker, not following the herd believing things unquestioningly. But in fact believing things unquestioningly and following his leaders like a sheep was exactly what he had been doing. His friend reminded him that to be truly open-minded, he ought to be just as questioning about his own beliefs as he was about the beliefs he was denying. He thought about how much time he'd spent finding evidence to prove his case, compared with how much he'd looked for evidence that it wasn't true. Then he realised the mistakes he'd been making all that time!
That night, he went to the websites of people he would have previously dismissed as liars being paid to spread misinformation by the government. He looked for evidence against his beliefs, willing to accept it if it was convincing this time, and he found it was very strong. He discovered that some of the things they pointed out should have been glaringly obvious to him.
He now believes he would have changed his mind a lot sooner if someone had pointed out all the errors in logic in his arguments, rather than him feeling as if he was in a competition to produce the most convincing evidence, duelling fact for fact, trying all the time to prove his position was the best.
So perhaps that could work with other people as well. Here are several errors in logic people sometimes make:
The term Ad Hominem is Latin for "against the man". It means you reject a claim a person's making because of who they are or something you accuse them of, rather than because you can prove there's something wrong with the claim they're making. An example is:
"Well that psychiatrist's obviously biased; he gets money from drug companies to promote their products, so what he says can't be trusted".
The fact that a psychiatrist gets money from drug companies might well make him biased so it's a good reason to treat what he says with caution; but the fact he has those interests in itself does not inevitably mean his claim can't be believed. What he says might be accurate, so the claim itself might well be worth looking into; it can't be dismissed out of hand.
Other examples include:
"Well he's pretty stupid; you can't really believe anything he says."
Even if he is a bit stupid, that doesn't mean you can't believe anything he says.
"That's just what I'd expect a government supporter to say!"
While a government supporter might be biased in favour of the government, it doesn't mean everything they say about them is wrong and can be dismissed because they're a government supporter.
"You have to say that because that's what your religion teaches and you have to follow it no matter what."
That's not relevant to whether what the person said is true or not.
When someone who makes a claim is insulted in response to it by being called stupid or just a sheep following a religion or the government or whatever, it might be tempting for them to respond with an insult in turn, especially if they've become angry. Or it might be tempting for them to discuss whether what the person said about them is true, for instance whether they really are an unthinking supporter of some organisation. But then the point they made might well be forgotten in the argument about them personally that follows. What they can do instead is to point out that the person has just made a logical fallacy in suggesting that a claim can be dismissed because it's promoted by them, and on the basis of a personal attack that's irrelevant to the claim itself.
That's where a person's claim is rejected because it seems they behave as if they don't really believe it so they're being hypocritical, or they said something earlier that contradicts it. Examples include:
"You said drinking alcohol was really bad for people earlier, but look, you're doing it! You can't think it's that bad then, so why should we take what you said seriously?"
What a person does doesn't make their claim false. It has to be judged on its own merits.
There are circumstances where if a person makes a claim about something and then acts as if it isn't true, it's good to be suspicious, for instance if they might have said what they said as a joke or they were playing a trick. But to dismiss a serious claim out of hand because the person who made it acts as if they don't believe it, isn't a logical thing to do, because the evidence for and against it is being ignored.
"Come on, you didn't used to like the government, but now you say they're doing a good job? I can't believe you're serious when you used to despise them so much."
What the person's saying about the government can't be considered wrong just because it contradicts something else they said about it. After all, they might have simply looked into things more thoroughly and changed their mind, or circumstances might have changed so they're judging by different things than they were before.
"You think I should be in bed by now, mother? Well you're still up."
Apart from the fact there's nothing wrong with parents staying up later, the fact they might still be up doesn't mean it wouldn't have been advisable for the child to be in bed so they can get a good night's sleep.
"You don't believe clothing should be made out of material that comes from animals that have been killed? But you're wearing a leather jacket."
There's nothing wrong with questioning whether the person really does believe what they said they believe. What's illogical is if someone talks as if they assume the actual claim the person is making is wrong, simply because they're behaving as if it is.
Related is the logical fallacy of justifying something you do on the grounds that the person who's accusing you of doing it does it themselves. For instance, a person might say,
"You don't think I'm safe around children because I'm aggressive? So, you can get aggressive."
What the person making the accusation does is irrelevant to whether what they're saying about the other person is true. It's a good idea to bring it up if it's a concern, but not in order simply to justify one's own behaviour. Two wrongs don't make a right.
Naturally, it's not a logical error to question why on earth someone wants to complain about something someone else does when they happily do it themselves. But it is a logical fallacy to justify something you do, or reject a claim someone makes, because of what they do; it means you're ignoring the evidence for and against the claim itself.
That's where a person tries to back up a claim they've made by saying they can guarantee what they're saying is true because the person they got the information from is an authority on the subject. They might be, but unless others can be sure they're reputable and some evidence for their claims is given, it isn't a good argument to just say you know something's true because someone important or educated in the field, or worse, in a field that sounds important but isn't really relevant to the particular area of expertise at all, said it.
Or a person might say they know their stuff because of who they themselves are, for instance saying they can be trusted when they say a new drug will be effective with only mild side-effects because they're a highly educated person with a master's degree in biology. If even drug companies with all their research into drugs and what effects they have on the body have to do clinical trials on drugs to see whether they're effective and what side effects they have, a person who just has a couple of biology degrees, no matter how impressive they sound, can't be automatically trusted to know whether a new drug's effective. They need to at least explain why they think it'll be effective before anyone should judge how well they know their stuff.
Or if a priest says he knows what he's saying about the Bible because after all, he is a priest, his claim to know what he's saying shouldn't be automatically accepted, because being a priest doesn't necessarily mean he knows what he's talking about. Only if he can make a convincing case as the why the claim itself is true should he be considered persuasive.
Or if someone says that as a scientist, he should think he's familiar enough with the scientific method to know psychology's all rubbish, to give another example, he shouldn't be considered impressive just because he can say that. Just because he's a scientist, it doesn't necessarily follow that he knows enough about psychology to make such a claim. It might turn out that he doesn't know much at all about it, even if he's a genuine expert in other areas. Unless he can back up what he says with convincing evidence, he doesn't need to be taken seriously.
Or, to give yet another example, if someone gets irritable when challenged on something during a conversation about mental illness and he says, "Look, I've worked in the mental health profession for ten years!" that shouldn't be considered relevant unless he can actually back up the claim he made in the first place with evidence. After all, who knows whether he even did a good job in his career.
A person might say a lot of things that could be taken as evidence by people less educated in the subject. But rather than just accepting them, it's a good idea for anyone to ask for the person to clarify what they're saying in words they can understand, if they're using jargon or unnecessarily big words, and also to ask them to provide more evidence for claims they're making, and to ask other questions.
Naturally, some claims to be a trustworthy source because of expertise in the subject can be relied on more than others. For instance, if an organisation generally thought to be reputable puts out some information to help the public about something they know a lot about, such as medical advice, it doesn't need to be thought necessary that they back up what they say with evidence to prove they know what they're talking about.
Advertisers often very successfully use the fallacy of appeal to authority to get people to buy products. For instance, people can think that if a famous actor is advertising something, it must be good, because they assume the actor wouldn't let their name be associated with something that wasn't. But the actor might not actually know much about the product at all. It might have flaws the actor didn't know about. Just because they're good at acting, it doesn't mean they're good at knowing how effective an anti-ageing cream will be, for example. Even if they can say it worked for them, that doesn't need to impress anyone, because people have no way of knowing whether the cream did make a difference, or whether they're just wishful thinking, wanting to think it did because they'll be paid to say it, or whether they perhaps started using different make-up at around the same time as they started using the cream, and that's what really improved their looks in front of the camera, to give another example, and so on.
On the other hand, if a history professor who's studied a particular episode in history in detail makes claims about it, more confidence can be put in what he says, because he will have done quite a bit of research on the subject before coming to his conclusions.
Then again, if what he says is known to be disputed by other experts, then for him to appeal to his expertise as evidence he's correct shouldn't be convincing.
Those who hear him might not know if there are other experts disputing what he says. But if what the professor says sounds very plausible and there aren't any known significant disagreements with his position, then putting a fair amount of confidence in what he says but keeping an open mind to the possibility he's wrong would be a fairly reasonable reaction. It would be impractical to look for evidence for everything; after all, there wouldn't be time to do much else in life if every single claim anyone made was thoroughly checked out. Sometimes, it's best to trust a person's credentials to make them competent to talk about something.
Another way an appeal to authority can be misleading is if someone doesn't identify what the authority is, but says they're sure something's true based on a book they read, or a television programme they watched, or they might say, "Scientists say that" or "experts believe" or "They say". If they don't give more details about it, there's no way of knowing whether the people they got the information from knew what they were talking about. The person might sound persuasive, perhaps saying something like, "I've got a book by an expert that explains clearly how it's possible to do this". But without knowing whether the author really is an expert and the information is good, there's no way of knowing whether it can be trusted.
That's when people say things that mean they think that because most people believe something, it must be true. In reality, just because most people believe something, it doesn't mean it's true at all. Most people believe there are real psychics, for example, but science has never been able to prove real ones exist, so the fact most people believe in them doesn't prove anything. Before it was discovered smoking can give people lung cancer, most people probably believed there wasn't much wrong with it.
Examples of a person using appeal to belief could include:
"Come on, most people think it's perfectly allright to mock people like that. You're just a whiner. Lighten up."
The fact that most people believe it's allright, if that's even true, which it might not be, doesn't mean it really is allright, since after all, some people might get upset by it, and it may be that most people don't take that into account.
"Come on, cannabis is harmless. Ask any cannabis user and they'll tell you."
Whether or not they will tell you that is open to question. Anyone who says they will is making an assumption and passing it off as a fact. And even if all of them do say it's harmless, it doesn't mean they're basing what they say on actual research. The opinions of many of them won't be able to be assumed to be reliable, and many might not even know the answer.
There are exceptions to the rule that just because most people believe something it doesn't mean it's true. It isn't always a logical fallacy to think that, because sometimes, if most people believe something, it can almost be taken as a guarantee it is true. For instance, if someone visiting an area asks several people where the cheapest cafes are and several people give them the same names and say they believe they're the cheapest, there's a high likelihood the information's reliable.
Another circumstance is where people might say burping is bad manners. It isn't intrinsically bad, but it becomes accepted as bad manners when most people think it is; the fact that most people think it is makes the belief a cultural standard. It might not necessarily be a good one, and that might be worth thinking about, but it doesn't change the fact that it is one because most people believe it is.
That's where someone says something's acceptable or justifiable because most people do it. Of course, even if most people do do something, that doesn't make it moral or justified. Someone using that fallacy might say something like:
"Yes I know we're compromising safety here, but don't worry, everyone does it in this business."
It's doubtful that "everyone" would be, and how would the person know, in any case? But even if lots of people do, that might mean it isn't perceived as that dangerous, or it could be that there are just a lot of businesses that aren't very safety-conscious. In any case, the fact that a lot of people cut corners doesn't mean there's nothing to worry about and it's acceptable for everyone to do it.
Another example might be:
"Yeah I know there's some corruption in this department, but nothing goes on here that doesn't go on in other government departments."
Again, that doesn't make it acceptable.
To give another example:
"I suppose it's wrong to have an affair, but so many people are doing it nowadays you'd feel a fool not doing it."
The amount of people who do it, which is open to question anyway, shouldn't determine someone's opinion of how good or bad a thing it is to do; there are far more important things to consider, such as whether it would hurt the marriage if it was found out. No matter how many people do something, it doesn't make it morally right.
That's when someone says they believe something, or don't believe something, because something bad or good would happen if they did or didn't, something that isn't actually related to the belief itself. In other words, it's different from saying something like, "I believe the pubs should close early because if they were open all night there would be more trouble". It's when the reason to believe something isn't directly to do with whether the belief is true but more to do with something like fear of what would happen to you if you were forced not to believe it. Examples could include:
"I can't believe the government would do that. If I did, I couldn't sleep at night."
It might be true that the person wouldn't be able to sleep at night if they did believe it, but that has nothing to do with whether it's true or not.
"I believe in angels because it's very comforting."
It might be comforting, but again, that has nothing to do with whether they're real or not.
That's when someone tries to convince people of something by stirring up emotions in them, rather than reasoning something through. They might do it unwittingly or in a calculated way. Advertisers do it a lot, not presenting much evidence for their product's benefits, but persuading people to buy it by evoking feel-good emotions in them. For instance, an advert for cider might have an image of someone feeling stressed, then pouring a drink and visibly relaxing and then starting to enjoy themselves as they begin to drink. That'll be meant to convince people to buy cider by filling their minds with thoughts of pleasure and getting them to associate them with it.
Or a politician might want to drum up support for a war, and broadcast speeches full of attacks on the people, designed to stir up hatred against them that'll move people to action against them, without actually discussing the reasons why they think it's a good idea to go to war or what disadvantages there might be. Image after image of violent acts committed by the enemy in a previous war might be broadcast on television, and they might enrage people and convince them the enemy needs to take a beating. They might forget to consider whether going to war against them is deserved this time and whether it's strategically a good idea, or whether there are other options that would be more humane and effective. They might forget to ask themselves whether the enemy are a brutal people now and whether fighting them might kill a lot of innocent civilians who don't even agree with what their government are doing. A person full of anger or hatred can act impulsively, doing the first thing that comes into their heads, and can regret it later.
Or a preacher might do sermons full of hate speech against homosexuals or some other group, calling what they do evil and saying that anyone who tolerates them is doing the devil's work. Some people might go out of the services full of hatred, disowning their children if they turn out to be gay, being thoroughly convinced by the emotions stirred up in them, and not once questioning their beliefs and looking into what other people with differing points of view have to say, to educate themselves about the facts. They might not even realise there are people with differing points of view if they're too ready to believe the preacher because he's an authority figure.
In an argument, someone using the logical fallacy of appeal to emotion might, for instance, declare that the law doesn't punish criminals harshly enough, and seek to prove it by telling an upsetting story about one person they know who was injured by a criminal and the criminal got an unreasonably light sentence. While the person they're talking about might deserve sympathy, the fact that they have only mentioned the case of that one person does not prove the entire law is soft on criminals, which is what they're claiming. Bringing up one case only proves that in that particular instance, justice wasn't done. People might be angered by the story, but they shouldn't let that convince them the person's claim about the whole law being soft on crime is valid.
Appeals to emotion aren't always bad. For instance, a motivational speaker will be far more effective if they spur people to positive action by getting them enthused rather than by giving a dry speech discussing the pros and cons of working harder. But when people's emotions get stirred up, they ought to watch that they're not being influenced to do something they might later regret by having their emotions appealed to, so they want to do something on impulse rather than calmly reasoning through whether it's a good idea and what it's likely to achieve and its disadvantages.
Beware of falsely accusing someone of committing the logical fallacy of appealing to emotion. They might make a point and illustrate it with something that evokes emotion in the reader or listener; but provided they're not substituting an attempt to stir up emotions for valid evidence, they can't be accused of making a logical fallacy.
That's related to appealing to emotion, because it's where people say a lot of long words which give people confidence they're doing something good, and may even buoy them up with a sense of patriotism or commitment to a cause that leads them to do rash things, when the words don't actually mean much by themselves. They give a nice feeling that something good's being done that it would be nice to support, when in reality, without an explanation of exactly what they signify, they don't on their own mean as much as the person using them is hoping people will think they mean. Imagine a politician's describing changes to the health service, or a war they want people to join, and they use the following words. They make it sound as if they're doing something good and the previous system or the enemy is bad, but really, if they filled a speech with words like this but didn't explain any of the details of their plans, would you be any the wiser at the end of the speech about what they were going to do than you were at the beginning? If you were confident they must be doing something good because of the words being used, you'd be committing a logical fallacy in your mind:
If politicians or other authority figures wanted to persuade people to do something for them or to accept a new system, and it had a lot of disadvantages, instead of frankly discussing the pros and cons of it and just what people would have to lose or suffer if the scheme was adopted, they might do a speech full of words like that that made it sound as if they were promising great things, and that sacrifice was necessary for great good to triumph over evil. People might be carried along by the feel-good words and the ones bringing threats to mind. But the one using the words hasn't said much at all. To give some examples that illustrate that:
"This will bring much-needed modernisation to the system. It will unharness great potential and lead to wonderful innovations, great improvements, and an increase in quality and standards. We are the party of change, allowing many people to fulfil their aspirations and achieve great success."
That sounds great. But what, in effect, does any of that mean? Unless examples are given of just what, in practical terms, is going to happen, they're just feel-good words that could mean any number of things. The person making those claims hasn't explained what evidence makes them sure their programme will be a good one, what advantages and disadvantages it'll bring, and just what kind of changes people can expect to have to face. And if people are convinced by them that things are going to be wonderful and they aren't, so they challenge the one who made that glowing promise about how things would be great, asking them why things aren't that good after all, the person can simply say they didn't mean quite what the person challenging them thinks they meant.
Sometimes things can be made deliberately ambiguous because it means a government or other organisation can make a promise to the public that sounds good, but they're not in reality committing themselves to achieving that much.
"This is an evil regime. We're fighting to bring freedom and democracy to its people, to raise standards in their country and to defeat the perpetrators of terror. Our valiant principles must defeat theirs. It's time for all brave-hearted men to do their patriotic duty and fight to bring moral values back to these people!"
Words like that might stir up patriotic fervour in some people and make them think the government are good and right and it'll be honourable to fight for them. But really, what do they mean? Such sentiments don't say anything about whether there's a plan of action in place to make sure things do improve in the country; there isn't any really decent explanation of the reason the regime's so bad it needs to be removed and why it has to be done soon; they haven't said anything about the dangers people motivated to action by them will face on the battlefield; they haven't explained why warlike activity is necessary rather than some other course of action, and so on.
That's where someone tries to get someone to believe or do something, or when someone says they're going to believe or do it, not because they can reason things through and persuade anyone that it makes good logical sense, but for fear of the consequences of not doing so.
Examples include things like:
"You'd better agree that the new company policy is the best one if you want to keep your job."
It's the kind of tactic bullies use to get their way.
"You're wrong, and if you don't vote against this new policy we'll vote you out of office."
Such a tactic could be used as a last resort when all attempts to reason logically have failed because the person just won't listen to reason, but if it's taken as the first approach, it suggests the person making the threat really hasn't thought through their reasons for not liking what they're opposing and whether they really are good ones.
"If you don't give up vegetarianism, I'm going to eat a lot more meat and make you watch me chewing on those animals you love so much."
This says nothing about whether vegetarianism's right or wrong. The tactic can be used by people who haven't got a good argument.
"There's a lot of proof the Bible's true. Everyone who refuses to accept that truth will burn in Hell."
If there's a lot of proof for it, the person saying so ought to be able to explain it, rather than resorting to trying to scare people into believing it.
"... In any case, I know your phone number and I know where you live. Have I mentioned I am licensed to carry concealed weapons?"
That's clearly an attempt to win an argument by bullying. The person making the threat might not have put forward a good case for what they're trying to get the other person to think or do at all. In fact, a good question to ask them would be whether they can put forward a good case for it, and if so, what is it, and why don't they feel confident to win the argument by putting it forward and trying to persuade with reason and logic? If their reasons for wanting what they want are that good, why aren't they sure they can persuade others by explaining their reasons, rather than using intimidation tactics?
Of course, there are circumstances where making threats is a logical thing to do, for instance if it's the only way to stop someone harming another. But if it's possible to reason with them, supposing the threat isn't immediate so you have time, and if you're actually trying to persuade them you've got a good reason for believing what you do, then resorting to intimidation is not a logical thing to do.
"You know, Professor, I really need to get an A in this class. I'd like to call in during your office hours later to talk about my grade with you. I'll be in your building anyway, visiting my father. He's your dean, by the way. See you later."
That's trying to get the professor to give a good grade not because the work is good enough; chances are it isn't, or the person wouldn't feel the need to use veiled threats; but it's trying to make the professor give a good mark for fear of what'll happen otherwise. If the person wants a good grade, they ought to work for it. If they're not good enough, chances are they won't do too well in their chosen career if it's one that demands high standards. So the logical thing to do would be to aim for something else instead.
That's where someone assumes something's true just because they heard someone say it was, or because they know someone for whom it is true, and assume that that must mean it's true for everyone; or they think it's true for themselves or for someone they know, when in reality they're mistaken because something else happened instead. All in all, any evidence like that will never be as reliable as scientific evidence where lots of people are studied and steps are taken to make sure what they think is happening really is, such as if they think a drug's working but in reality it might just be the placebo effect, so they give some people a placebo to see how effective it is compared to how effective the drug is.
"I don't believe smoking can cause cancer. My grandmother smoked twenty a day. She also had a glass of whisky a day. She didn't die till she was 95, and she was healthy till then."
That may be true, but just because one person escapes ill effects of smoking, it doesn't mean everyone will. No one claims that everyone who smokes will get a serious illness, just that it increases your chances of getting certain illnesses.
"I know homeopathy works. I'm a homeopath, and I've had dozens of patients tell me they've got better after coming to see me."
That may be true; but how do you know it was what you did that cured them? A lot of them might have been suffering from things that get better on their own fairly quickly anyway. Some of them might have been taking other things besides what you recommended, so they think it was your treatment that helped them when it was really something else. Some people might be suffering from diseases that naturally get better and worse, and they might have naturally gone into a phase of the disease that wasn't so bad after they saw you. And how many people have come back to you and said your treatment didn't help? Perhaps not many. That won't necessarily be because it's effective; it might be because a lot of people give up on things and just quietly move on. And of course if anyone died, they won't be back to tell the tale. So the anecdotes you can tell about people getting better after they were treated by you can't be taken as conclusive evidence.
"I know vaccinations can cause brain damage in children. I read a post on an Internet forum from someone who said her child was lively and intelligent until around the time she had a vaccine, and then she went quiet and stopped being interested in the world and now she's mentally retarded."
That's obviously tragic. But can you be sure it was the vaccine that did it? What if it was a genetic disease that happened to kick in at around the same time as she had the vaccine, or some kind of terrible infection she caught? Could she have had a nasty accident, such as if a carer she was left with dropped her and she fell on her head? Or if it was the vaccine, how can you be sure it was more than a once-in-a-million bad reaction? Is it worth the risk of what might happen if you warn everyone off getting their children vaccinated? A lot of the diseases eliminated by vaccination are killers. Some can cause brain damage themselves. You haven't even said which vaccine it was, but are assuming all of them are just as bad. It's better to rely on scientific research where they test the vaccine on lots of people and study the results.
"The summers were warmer when I was young. I remember we had glorious summers in those days. We had such fun at the seaside.
Perhaps that's true; but memory isn't always reliable, because it's so easy to forget things, or just remember some parts and not others and start thinking everything was like the most memorable parts. The most glorious days would stick in the mind more; it would be easier to forget the days spent sitting in the house not doing much because it was drizzly, unless there were a surprising amount of them. Also, a week or two of overcast weather might start a person looking back with fondness to hot days they remember in the past, and they might think it's been overcast and cool for so long that summers can't be what they used to be; but in reality, there might always have been years like that or weeks during most summers like that, but they've just forgotten. So the impression that summers used to be warmer could simply be an unintentional distortion of memory.
"Reincarnation must be real. I read a book about a woman who was hypnotised and she remembered a past life 150 years ago and talked about details she can't have made up because it says life was like that in the history books. Also, I heard about a little boy who believed he was the reincarnation of someone who'd died a few years before, and he talked about details he couldn't have known.
That's still a flimsy reason to believe something, because there are possible entirely non-supernatural explanations for what happened. Even if you don't know what they might be, its as well to bear in mind that there might be some, and not to base a whole belief on the word of just a few people. As for reincarnation, it's a good example of that, because people recalling past lives under hypnosis isn't good evidence for it at all; people can fantasize a lot when they're hypnotised, especially if they're being asked questions that encourage them to think of more and more detail. And they can recall details they read in books or watched in films and think they happened to them. As for very young people believing they're reincarnations of others, their parents could have trained many of them to pretend to really believe they're whoever they're claiming to be, teaching them about their lives, because they want to try to make money from the relatives of the person they're claiming to be or to make money by selling the story to a paper and so on. Even if a hundred children said they were reincarnations of people who'd recently died, it wouldn't rule out the possibility that many or all could be playing a part in a con by the parents to make money.
"Eat raw onions. I heard about someone on a Japanese island who ate raw onions every day and lived to 120."
Really? Can you be sure the story's true? If it is, can you be sure it was the onions that led to his long life? After all, he must have done lots of other things as well, so how do you know it wasn't one of those? and there might be lots of other people on the island who eat raw onions but die much younger.
Beware of falsely accusing someone of committing the logical fallacy of using anecdotal evidence. People can often want to illustrate a point they're making by telling a story, to demonstrate the harm something can do with an example of the harm it did do to someone it happened to, or to suggest that if it happened to someone, chances are it's happening to others also, or to catch a listener's attention with something interesting, or to engage their emotions so they appreciate more fully the impact something's having on people; but they can only be accused of using anecdotal evidence if they actually substitute such a story for valid evidence. Telling an anecdote in itself is not a logical fallacy.
That's where someone tries to persuade another person of something by flattering them so they feel more favourable to the idea of doing it, regardless of how advisable a thing it is to do. The flatterer might not make a good case for why what they want's a good thing at all. They'll be hoping the compliments will appeal to the vanity of the person and they'll think more favourably about doing what they want. Falling for persuasion by flattery could mean making disastrous decisions sometimes, because the advantages and disadvantages of doing a thing might not be weighed up. A decision might be made not because it's the best one in the circumstances, but because the person who makes it wants to please the flatterer, because they're glad they seem to think highly of them. Examples of appeal to flattery include:
"I have a lot of confidence in your judgment. You've always been a good leader. And you know you're a good friend of mine. Now I really do think going to war would be a good idea. They're a terrible threat. They've been building up their arms for years; they need to be stopped. I'm sure you'll make a fantastic wartime leader, and under your leadership we'll easily win."
If the compliments go on like that, the flattery might blind the leader to the fact that a good case hasn't been made for war. There has been no discussion of the costs and benefits and weighing up of alternative courses of action and their advantages and disadvantages. No consultation with independent advisers who could frankly discuss such things. Falling for flattery can cause people to make decisions for reasons that aren't very good at all.
"I think your ideas are brilliant, professor. I'm going to say a lot about them in my paper. ... I hope you don't mind if I go a little over the deadline for handing it in."
If the professor does the student the favour of letting him take longer than most students have to do the paper, he's doing it not because there's a logical reason to do it, but because he's fallen for a softening-up tactic.
That's where someone assumes or tries to persuade another person that something's better or correct because it's newer or new. In reality, just because something's new, it doesn't automatically make it right or better. Often newer things are better, because they're more advanced, better quality in the case of food, and so on. But it doesn't follow that every new thing will be.
Examples of the fallacy might include:
"I think we should update our business plan. The trendiest thing in marketing techniques now is the FI method. It's the latest thing out of the think tank. It's so new that the ink on the reports is still drying. Yes, you might say our current marketing technique's quite effective, but we have to stay on the cutting edge. That means new ideas and new techniques have to be used. The FI method's new, so it's bound to be better than some old technique that's been around for ages."
The old and new techniques should be assessed on their merits, their advantages and disadvantages and likelihood of effectiveness. If no attempt to explain why something new is better is made, but people are expected to accept it just because it's new, then a logical fallacy is being made.
"A new and better morality is sweeping the country. No longer do we cling to outmoded ideas! People have new enlightened ways of thinking! Things are being accepted that weren't tolerated before. That's progress!"
If no attempt is made to explain just why the newer morality is supposedly better and what was wrong with the old one, it's not a good argument at all to say the newer morality's better just because it's new.
That's where someone tries to convince another person to think or do something not because they can give them good reasons for it, but because they deserve pity because of something. Or someone can commit it if they do something because they feel sorry for a person, when their better judgment would tell them not to because there are good reasons why it's a bad idea.
Examples of it include:
"I think I was too hasty in asking her to marry me. I really don't think we're right for each other after all. But I have to go through with it. It would break her heart if I called the wedding off."
It might not break her heart as much as divorcing several years down the line when you could have kids who might also be very upset will. Bear in mind that's a possibility. If not calling it off could have worse long-term consequences than calling it off, then the fairer and more logical thing to do in reality would be to call it off, though logical thinking was obviously a bit lacking earlier in the relationship to have enabled it to get this far. Calling it off will no doubt be upsetting for both of you, so you deserve sympathy. But if it's in danger of breaking up anyway, sooner's probably better than later. On the other hand, thinking logically now might still lead to you deciding to go ahead with it, because it might help you work out how to do your best to make the relationship better.
"Please give me a high grade. I won't get into my chosen career if I don't get one and that would really upset me."
How well would the person do in their chosen career anyway if they're not good enough to get the grades required to enter it? Giving higher grades out of pity wouldn't be a logical thing to do. And trying to get a higher grade by appealing to someone's pity rather than by working harder is using a logical fallacy.
"We should give him the manager's job; he needs the money; he's looking after a big family."
He might need the money, but if it turns out he can't do the manager's job, he might end up in a worse position than he's in now. Besides, the company needs someone who's going to be good at the job. There is no discussion here of whether he would be or not. Why is that? Pity should never be the only consideration. There might be other ways he could get more money. Why resort to what seems the most obvious thing when it might not even be the best?
Naturally it's not wrong to do things for people out of pity. But it isn't logical to argue that something should be done simply out of pity, ignoring the questions of whether it would be a genuinely advisable thing to do.
That's when someone believes, or tries to convince others, that something is good or right just because a lot of other people like or approve of it. In reality, even if they do, that isn't evidence for how good it really is.
"My fellow Americans...there has been some talk that the government is invading people's privacy by allowing police to enter peoples' homes without the warrants traditionally required by the Constitution. However, these are dangerous times and dangerous times require appropriate actions. I have in my office thousands of letters from people who let me know, in no uncertain terms, that they heartily endorse the war against crime in these United States. Because of this overwhelming approval, it is evident that the police are doing the right thing."
Since we don't know whether the reasons for those people's approval are good ones, and even whether they know what's really going on, or also whether although there are a lot of letters, the people who wrote them are actually in a minority of the population who believe something most people think they have good reasons not to believe, we can't conclude anything at all from the fact the politician says lots of people like what they're doing. Even if they do, it doesn't mean it's a good thing to do. Without knowing the reasons why the government are allowing what they are, anyone who judges that it is good because a politician says a lot of people think it is has fallen for a logical fallacy. They in reality have no way of knowing whether it's good or not till they know more facts.
"I read the other day that most people really like the new gun control laws. I was sort of suspicious of them, but I suppose if most people like them, then they must be okay."
Without knowing the reasons most people like them, it's impossible to know whether they're good reasons. A lot of people might like them for bad reasons. Besides, just because someone says most people like something, it doesn't mean most people really do. It might be worth questioning how the person who claims they do knows it.
"What's wrong with you? Most people love jokes like this."
In reality, even if that's true, it doesn't mean they're genuinely good or that everyone should like them. If it means anything, it might mean most people have bad taste. But again, how could anyone know that "most" people like them? Whatever the truth of the matter, the fact that some people like them isn't evidence for the idea that everyone should or that they're good.
That's where instead of putting forward logical reasons to oppose what someone's saying, a person just ridicules it, as if mocking it is evidence it isn't true. Ridicule might sometimes have a place, but no matter how much ridicule is heaped on something, it doesn't mean that thing's wrong, and anyone who thinks ridicule's a valid substitute for explaining good reasons for something they believe to be true is mistaken. For instance, if someone said, "Two and two make four" and someone else said, "That's the stupidest thing I've ever heard. Didn't they teach you anything worthwhile at school? You must have gone to a school for retards! How can anyone not know two and two are five?" that would hardly mean the person who said two and two make four was wrong!
Ridiculing something in itself isn't fallacious. Ridicule can be used to bring a point home, but only if it's backed up by a reasonable argument. Sometimes, someone makes a false claim and it's possible to show that if it were to be logically followed to its conclusion, the conclusion would be ridiculous. For instance, if someone claimed that members of a minority group couldn't be racist, someone else could say the claim was absurd, and bring the point home by pointing out that if it was true, it would mean that since white males are a minority in the world, they can't be racist, which means the Nazis and the Ku Klux Klan weren't racist. They might be talking about "oppressed" minorities, but Hitler himself claimed German speakers living in the part of the world he grew up in were oppressed by the Cheques. Does that make him not racist? That's a form of logic by ridicule. But ridicule that doesn't try to prove a point but is just mockery is no substitute for logical argument if the person using it actually wants to get a point across. In fact, it can make the person being ridiculed angry, and that can make them stop listening.
Examples of substituting mockery for providing evidence to support a point of view include:
"You think it's a good idea to do that? That's laughable!"
That says nothing whatsoever about why it isn't a good idea. Mocking someone's idea doesn't make a person right.
"You think you can get a job as a train driver? Yeah, when hell freezes over! You'd probably crash it on your first day. Ha ha ha."
That explains nothing whatsoever about why the person doesn't think the person they're mocking could be one. There's no way of knowing whether they've got good reasons for thinking it or not.
That's when someone argues against something by saying something likely to influence a person to change their mind out of spite, rather than because there's good evidence to do so. Examples include:
"You want to vote for her? Remember last year when you were standing for the committee. She didn't vote for you, did she."
If the person decides to vote for someone else instead of the person they originally intended to vote for out of spite when they're reminded of that, they're not voting for who they think will be the best person for the job; they're changing their mind for reasons that aren't logical. Also, it's not logical to try to persuade someone to change their mind for any reasons other than sensible ones to do with what's genuinely best.
"Yes, I know you think his idea will really help this department save money, but remember last year when he showed you up in public by criticising one of your ideas in front of the whole department? How about going with my idea instead?"
If the person does so, they're not doing it for sensible reasons but they're letting base emotion dictate to them and get the better of their better judgment, because what matters most is what idea will be best for the department. And anyone who tries to change another person's mind by saying something likely to give them bad feelings towards a person or thing, rather than trying to convince them with evidence that there's a good reason to change their mind, is using a logical fallacy.
That's when someone assumes that something's the best way of doing things or a good way because it's "always been done that way" or because it's older. In reality, traditional things are not always better at all, even when the tradition's been carried on for years. In some countries, for example, it's traditional to marry girls off in their early teens. That's hardly better than letting them grow up first.
People might prefer traditional things because it feels more comfortable than branching out and trying new things or it's easier to stick with something that's already known than to learn new things, but arguing that something's better simply because it's old or has always been done is not good reasoning. Something can't be better simply because it's traditional. There are circumstances where it's not unreasonable for someone to think certain old things are probably better, such as when they're talking about vintage wine. But that won't be better just because it's old, but because ageing does something to the quality of the taste.
Examples of the fallacy include:
"This church has believed this for nearly 2000 years. That's longer than any other church has believed what they believe. In fact, we're older than any other church. So I can confidently say we know best."
The simple fact that a belief and a church is older than others does not make it better.
"I'm an old lawyer. I do things in the traditional old way. So you'll know you'll get quality with me."
A traditional old way doesn't guarantee quality. He hasn't even defined what he means by the old way, so there's no way of knowing whether it's really good or bad.
"I don't know why our gang fights the other one, but we've been doing it for decades and decades, so there must be a good reason for it."
It can't be assumed that just because something's been going on a long time there's a good reason for it. It might have started for a very bad reason, and it might simply be being carried on because of each gang's desire for revenge on the other one for past losses, and paranoia about what kind of people they are and fear of their intentions. To assume it must have been going on as long as it has for a good reason because if there was a bad reason it would have stopped is to commit a logical fallacy.
That's when someone holds a belief or changes their mind not because they have good evidence to do so, but because others in their group believe something different and they just assume it must be true, want to fit in or are scared of rejection if they form a different opinion. So they might say they believe something, but their reasons aren't good; they might not even know any good reasons to believe it. No matter how much pressure is put on someone to believe a certain thing, and by how many people, it doesn't make the claim right.
Sometimes people might have practical reasons for conforming to the beliefs of others, such as if they're in a religious group and they could be disowned by their family if they change their religion or abandon religion, and they really don't want that to happen. But arguing that something is true or telling yourself it is just because of fear of rejection or the need to fit in is logically fallacious. Examples include:
"All the cool people do it. Most of my friends do, and they look down on people who don't. So it must be what people are supposed to do and I'll do it."
There's no examination there of whether it's actually a sensible thing to do or whether the "cool" people have a good reason for doing it or not. What if it's actually harmful? Then it would surely be best not to do it no matter what they think, even if friends are lost over it. By whose definition are they "cool" anyway? Their own? Well naturally they're going to want to think they are. But perhaps lots of other people don't think they are at all and don't think what they do is good. They just don't talk about it so much. In any case, just doing something because they do it, without even thinking through whether it's a good idea, means doing it for a reason that's not a logical one.
"You say that opinion isn't acceptable around here? I didn't really mean it. I agree with you really."
The person's accepting the other's opinion not because there's better evidence for it than their own, but because they don't want to be ostracised. They might not really agree but just be saying so. Perhaps their own opinion's far more moral; but for fear of rejection and any other consequences, they're keeping quiet and going along with the others, ignoring the rights and wrongs of the matter. While that might be in their best interests, the logic of which opinion is best itself is being put aside.
"It's far more expensive than I can really afford, but I've just got to get that dress. It's the height of fashion now, and if I don't get it, what will the people at the club think of me!"
Apart from the fact that the people at the club might not think anything at all if the person doesn't get the dress so their concerns might be baseless, they're not getting it because it's a genuinely good, logical idea, but because they're worried about peer pressure, probably overly worried, or giving into vanity and the wish to be admired. If putting their own possibly baseless worries or shallow emotions above a logical consideration of whether getting it's a good idea will even harm their finances, it's even more illogical.
They're when someone argues in a way that really calls for the questions:
"Hang on, what's the beginning point of your attempt to prove this with logic? Or are you even going to try?
In other words, how can you prove what you're saying with logic, rather than saying that since you're sure one thing is true, some other thing must be true, and the other thing's true so the first thing must be? That just takes us round in circles, because you say you believe the first thing because you think the other's true, and you think the other's true because you're sure the first thing is. So the argument's a circle with no beginning or end, just going round and round.
Your assumption that the first thing's true isn't a good reason for believing anything else, because what if what you're assuming is true to start with isn't?
You're just assuming what you're beginning your argument with is true and expecting us to as well, when really, if you want us to believe you, you need to prove it's true with evidence instead, if it is."
The person's conclusion might not even follow logically from the first point they made in the argument, but in reality be exactly the same as it, but just disguised a bit. An example of that kind of thing is:
"We fully believe in the right of everyone to carry a gun in a tolerant country like this, because after all, it is a measure of people's freedoms in this country that they be allowed to be armed."
That's basically saying you believe it because ... you believe it. There's no discussion of why the thing's believed in the first place.
That example's similar to circular reasoning, though what someone says takes a more complex form in that. Examples include:
"It's always wrong to kill another person intentionally. The death penalty is an act of killing another person intentionally. Therefore the death penalty is wrong."
Who says it's always wrong to kill another person intentionally? Why is it? Perhaps it is. But in order to make a logical case, you need to explain the reasons why. It's not logical to just assume it's true and expect everyone else to agree once you've said it is.
"God must exist. Why? The Bible says so. You ask how I know the Bible's telling the truth? Because it was written on the orders of God."
That's basically saying God must exist ... because he says he does. It's just assumed that he says he does and therefore he must exist. No independent verification is given to support the case.
"You say you'd like another reference before deciding whether to offer me a job? Fine. My work colleague Bob will do. ... What, how do you know you can trust him? Oh he's trustworthy allright; I can vouch for that."
What? The interviewer's being asked to believe your work colleague is trustworthy because you say he is, and he's being asked to believe you're trustworthy because your colleague will say you are? Um, sorry, but it doesn't work like that. How can the interviewer tell either of you are trustworthy?
That's where someone makes a claim they can't or won't prove, and tries to justify the claim by saying it's up to others to disprove it, rather than it being up to them to prove it. Sometimes the claim might be totally unreasonable, yet still someone might claim they're going to believe it unless someone can prove it isn't true.
Or sometimes, if there isn't much evidence for a claim, it might be illogically thought by some that the opposite of it must be true, even though there's not much evidence for that either; and those trying to claim the opposite might claim a victory.
"The new therapy I'm promoting helps a lot of people. I'm going to do workshops all over the country teaching others to do it. What? You want proof it works? Well I'm sure it does, and if you want to raise concerns about it, you go ahead and prove it doesn't work. If you can't prove it doesn't work, I'll remain convinced it does."
If someone promoting a new therapy hasn't got much evidence it works, and they claim it's up to people to prove it doesn't work rather than for them to reassure people that it's a good one, then the therapy could even be dangerous and no one might know till it's damaged quite a few people and others do set out to prove it doesn't work.
"I think you're conspiring against me. No, why should I provide evidence you are? Prove to me that you're not if you want me to believe it."
Someone who makes an accusation against others should at least provide some evidence so the accused and anyone else can understand why they're making the accusation and the accused isn't under pressure to disprove something that came completely out of the blue, as they might be. It would be difficult to prove you haven't done something like plotting against someone. It would require convincing people that every hour of the day during the past weeks, you were doing something innocent. How could anyone prove that?
"I believe in God, and I'm going to keep on believing in him unless you can prove he doesn't exist, so there."
Belief in God might seem quite far-fetched to some. So it's only fair for the person stating a belief to explain why they believe. And it's illogical for a person to imply they have no reason for their belief but they're going to believe it anyway unless the person they're talking to happens to be able to disprove the belief. They might not be able to prove beyond dispute that their claim is true. But it would be reasonable for them to recognise that their claim might be wrong but to explain why they personally think it's true.
Sometimes the burden of proof will keep switching from one side to the other, since if one person says something that sounds like convincing proof, the other side will have to say something to prove it isn't true if they still think they're right. In response, the first side might say something else that sounds convincing, thus shifting the burden of proof back to the other side again, and so on.
That's where someone makes a claim, and instead of rebutting it with any evidence, someone else dismisses it, claiming the person would be bound to say what they said, because of some circumstance like financial interest, religion and so on. While that might be true in some cases, that in itself doesn't make a person's claim invalid. The logical way to rebut a claim is to provide evidence against it. While a person might be motivated to make a claim because of some interest, it can't be disproved by pointing to their self-interest. However, it's perfectly valid to treat it with a lot of caution if it seems to be particularly convenient to a person's interests and contradicts other findings, such as when research by a tobacco company concludes that smoking and lung cancer aren't linked after all. It isn't the person's affiliation with the tobacco company that makes the claim false though, naturally.
Examples of circumstantial ad hominem include:
"You think it's right to cut welfare spending? Well of course you would; you're a Republican. You're biased."
That says nothing to rebut the claim that it'll be good to cut welfare spending. It isn't logical to dismiss a claim simply because of who the person making it is.
"Well of course he's going to be anti-abortion; he's a religious priest. I don't think we should take any notice of it."
It may well be that his opinions on abortion have been formed entirely by what his religious doctrine tells him to think; but nevertheless, to dismiss a claim that abortion's wrong by saying nothing about the rights and wrongs of abortion but just saying he's bound to oppose it because of who he is does nothing to rebut his claim, and so it's a logical fallacy.
"Well of course you're going to say homeopathic remedies can kill pain; you're a homeopath. Now get out of here!"
Instead of rudely dismissing his claim because of who he is, he should be asked to justify it, and then the question of whether or not there's any truth in it can be examined.
Naturally, if someone's making a claim considered silly and there's no time or wish to examine it, it's reasonable not to take it seriously, and to want to move on to other things without examining it. But it's not logical to disbelieve it simply because of who the person making it is.
That means assuming that something which is true about the parts of a thing or just one of the things will be true of the whole of it or all those things together as well, in situations where it doesn't logically follow that it will be. Examples include:
"A tank uses up more fuel than a car. Therefore, all the tanks use up more of the world's fuel than all the cars."
Naturally this isn't true, because there are far more cars in the world than tanks. That simple fact has been missed.
"A tiger eats more food than humans. Therefore, tigers, as a group, eat more food than all the humans on earth."
This is untrue for the same reason; there are far more humans in the world to eat food than tigers.
"Every player on the team's a superstar! Therefore they're bound to make a great team."
That isn't necessarily so, since just because they're individually good players, it doesn't mean they'll work well together. Some might be asked to play in positions they're not used to, or they might all be told to adopt tactics that turn out not to be good, or they might all want the limelight rather than being team players so they'll try to compete with their team mates for it instead of co-operating as a team, and so on.
"Come on, you like pizza and you like lemonade. You're just bound to like this lemonade-drenched pizza."
That's obviously not so.
That's when one thing caused another thing, but someone thinks that other thing caused the first thing, without much evidence to think that. So they get it the wrong way around. Or sometimes it just isn't clear which thing caused which, or whether something totally different caused both of them, and yet someone will be sure, without much evidence at all, that one thing caused the other. Speculating that one thing caused the other will often be reasonable; but being sure of it with little evidence isn't.
"I think this new music should be banned. It's evil, with all those lyrics glorifying violence and abuse of women. What? You say the music might be a result of people living in that kind of culture, not the cause of problems? Or it might cause a few but it's probably far more usual that people who like doing that kind of thing are attracted to that kind of music, rather than it influencing them to be like that? I suppose it's possible, but I'm still convinced that things would be a whole lot better if this evil music didn't exist. It just wouldn't put ideas into their heads. So I'm going to use every ounce of my energy to campaign to get it banned."
It might be that there's some truth to what the person who wants the music banned is saying, but they haven't tried to prove there is with any evidence, or to find evidence before being so sure of themselves they want to put all the energy they have into a campaign to get it banned. They have no good reason to be sure of it in the absence of evidence, especially when they know it may well be the case that far more often, the opposite is true - people who are like that anyway are the ones attracted to that music.
"Ever since I started taking this antidepressant, my depression's got worse. It must be to do with what some people say about things getting worse before they get better. I'm going to have to increase the dose of tablets, whatever the doctor says."
And what if the saying about things getting worse before they get better just doesn't apply here at all? What if Your body's having a bad reaction to the antidepressant and it's actually causing the added depression? It could be downright dangerous to just assume things are bound to get worse before they get better and take more. Or what if the increase in depression has been caused by an unfortunate change of circumstances you happened to have at around the same time you started taking the tablets, and you'd be far better off trying to alter it than increasing the dose of antidepressants and putting up with it?
"Ever since I bought this new house, I've been feeling tired. There must be something in the atmosphere. I bet it's got something to do with why the previous owner sold it. I'm going to have an angry word with them. They didn't tell me about this."
Feeling tired might be caused by the atmosphere in the house or some toxin leaking from somewhere. But what if it isn't? Jumping to conclusions too hastily could lead to embarrassment. What if you're tired because of all the stress moving house caused and all the energy you put into it? What if it's some medical reason that just happened at around the same time as you moving?
"It's no wonder that kid's that naughty when his mum shouts at him like that. He's probably quite disturbed."
His naughtiness might well have something to do with the way his parents treat him. But it might not be as clear-cut as you think. What if part of the reason his mother shouts at him like that is because he's so naughty and it's the only way she knows of how to deal with it? What if one causes the other in a constant feedback loop where the behaviour of each of them is fuelled by the other and makes it worse?
That's where instead of responding to an opponent's actual argument, someone distorts it in some way, exaggerating it or misrepresenting it in another way, and responds to their twisted version, claiming it's what their opponent actually said and they're knocking it down as it deserves. Naturally, doing that is illogical, because it doesn't provide evidence against the real argument.
"The right honourable gentleman says he'd like to see military spending cut. So he wants to leave us defenceless! He thinks that if an enemy invades, we should just step aside and let them. I'm sure none of you agree with that!"
Of course, that's not what the person said at all.
"Peter says atheism's a valid position to hold. So he thinks it's perfectly allright for people to have no morals and to live for selfish pleasure, since there's nothing after death so you've got to make the most of life now. Well I don't think any of us can agree with that position, can we."
Peter said nothing of the kind. The speaker's imposing his idea of what atheism means on his interpretation of what Peter said, rather than logically analysing what he did say.
That's where someone thinks it's OK to do something wrong to someone just because they did it to them or someone else, or because they would have done something bad if they could have. There's no logical purpose to it unless they can be sure it'll deter the person from doing it again. Otherwise it just serves some emotional desire for retaliation or it's a justification for unethical behaviour. Examples include:
"She revealed my real name on that Internet forum. I'm going to post her address for everyone to see. I'm perfectly justified. Tit for tat, that's the way it is."
That could be dangerous, much more dangerous than someone just posting a name, and for what? Is it designed to stop her posting your name again or anything else about you? Do you have the slightest bit of evidence that it will actually do that? Or are you just doing it out of a childish desire for retaliation, heedless of the possible consequences, just as long as you get your emotional satisfaction in that few seconds it takes to post it? What if you become widely known as the person who posted someone's address on the forum and everyone thinks you're a nasty irresponsible numbskull for it from then on? You're just not thinking logically, are you. And are you really naive enough to believe "tit for tat" is merely a process where someone does something you don't like, you do something they won't like, and that's the end of it? Do you not think they're likely to want to do something else to get their own back on you? Then if you do something back because you believe another wrong will make things right, they might want to get their own back on you again, and it could just get nastier. Is it worth it?
"I think torturing terrorist suspects is a good thing; after all, they've killed some of our people."
Apart from the illogic of blaming people who are as yet only terrorist suspects of killing your people, do you have any evidence torture will actually do any good? Is it not possible it could make things worse, by damaging relations further between your country and the ones they come from? Have you done any investigation whatsoever into other means of getting information and how they compare with torture as regards how effective they are at getting it, such as the 'softening-up approach' where suspects are put in a friendly environment for a while where the idea is that the suspects' confidence is built up till they feel friendly enough to want to reveal information? If you found out that was a much more efficient way of getting information than torture, would you still prefer torture because you think they deserve it? If they're not tortured it doesn't mean they'll go free.
"They're doing some horrible things in our country; let's go to theirs and make some people there suffer."
And just what do you imagine you'll achieve by that? Do you think their government will think, "Gosh, if they're going to make some of our fellow countrymen suffer, we must stop what we're doing over there!" Don't you think that instead, there's a high likelihood they might think, "They really are barbarians! They deserve what's happening to them over there!" And they might do more of it. Look what America did after the 9/11 attacks in 2001, for example. Do you think harming some of them will give you some kind of emotional satisfaction? Well how will you feel this time in a month when you hear about what happened afterwards? What if some of your people who live in the country you want to harm people in think every one of your group must be like you and some other ones living there suffer because people want to take out their anger on them because of what you did? Don't you think there are other ways of protesting that will actually get the message across that you want to put across, rather than possibly a very different message from the one you were intending? Why should innocent people suffer anyway? Not everyone in that country agrees with what their government's policy towards your country is. You might be harming people who disagree with it. What if a lot of people disagree with it, or would if they knew more about it? Don't you think publicising what's going on and protesting strongly in the media might be far more effective than doing something nasty that might stop people caring about what's going on? After all, if more people know about the worst effects of it, more people might campaign to get their government to change their policies. And if the government thinks losing those people's support and that of others who have no confidence in them any more after finding out about what they're doing will mean lost votes at the next election, they might.
"I don't treat everyone like this. I've just been treating you like dirt because you criticise me too much so I have no respect for you."
Well, since your behaviour's obviously given them the impression that you're just a nasty person who treats everyone like that, do you not think responding to their criticism by behaving like that was a bit misguided, since it gave them a completely different message than the one you thought you were putting across? Do you still think it's a good idea, despite the fact it's given the wrong impression? Just what are you hoping to achieve? Is it changing their attitude and behaviour towards you in a good way, or is it just making it worse? On reflection, wouldn't you have to agree that two wrongs don't make a right?
Naturally it's sometimes true that parts of something have the same properties as the whole of it, such as part of the human body being made up of what the rest's made of. To state that wouldn't be a fallacy because there's so much evidence for it. But sometimes there either isn't enough evidence to draw the conclusion that part of a thing or a group and so on has the same characteristics as the entire thing put together, or the evidence contradicts the idea.
"This office block's huge. The offices in it must all be pretty big."
Not necessarily. There just might be a lot of them.
"America is a prosperous country. Therefore everyone in it must be wealthy."
"Ethiopia's a poor country. So everyone in it must be poorer than any one of us in the West."
Not necessarily at all. Some people in the West are very poor, and some countries considered poor have very rich elite classes.
That's when someone claims that either one thing is true or another one is, when in fact both things could be false, or there could be some truth in both of them but neither is entirely true. Or a person creating a false dilemma might claim that since one thing can be proven false, another thing just must be true. It's also called black-and-white thinking, ignoring other options and grey areas.
"As the Chancellor, it's my job to announce we'll have to cut spending on public services significantly. It's either that or this country spends more money than it can afford."
Really? Why does it have to be public services that suffer from funding cuts? Aren't there things less important that could have less money allotted to them? And aren't there other ways of raising money? Is it really either spending cuts or the country spends money it can't afford? Isn't putting an extra penny or two on income tax an option?
"Stop complaining about this place. Love it or leave it."
Actually there are other options, such as working to improve it.
"I'm sure he isn't a wife beater. You have to accept that if he was, he'd have an aggressive personality that we'd all be able to detect. Are you going to try to argue that he has, or are you going to accept like a sensible person that he's just not the type?"
Naturally those aren't the only two options. A wife beater quite likely won't be aggressive all the time; when wife beaters are in public, getting their own way so everything's going well for them, or making efforts to behave in a civilised way when it doesn't, they can seem friendly. Many can apparently be charming.
A real television advert was packed with false dilemmas, apparently to try to suck in customers by making them think using their services was the only decent option available. It was for a company helping people move house:
Is United right for your move? Ask yourself: do you want (A) a seamless professional move? Or (B) your possessions set on fire? (A) technology experts to set up your home network? Or (B) raccoons to run amok with your electronics? (A) portable containers to move yourself? Or (B) complete chaos? If you answered A, call United.
That's when someone thinks a claim someone makes, or a thing, is good or bad simply because of its origins. Examples include:
"You think milk is bad for you? Well I've always been brought up to believe it's good and healthy. I'm not abandoning that belief in a hurry!"
If they can explain good reasons why they believe milk is good and healthy, and they cast serious doubt on the other person's claim that milk's bad for you, that's fair enough. But simply believing that what you were brought up to believe is superior because you were brought up to believe it is not believing something for a good reason, and suggesting it is is a logical fallacy.
"I find your use of the word 'handicapped' offensive. I feel as if you've just insulted me. Do you know it originated when a lot of disabled people had to beg, cap in hand, because they couldn't get work and there wasn't much of a welfare state to support them? If you continue to use that word, I'm going to assume you're disablist."
It's illogical to be offended because someone used a word they probably don't know the origins of. Even if they do, they're unlikely to be using it because they think disabled people are beggars, but simply because it's the word they've heard most commonly used. It's even more illogical to develop unfavourable views about a person just because they don't stop using a word they're in the habit of using. There just isn't enough evidence that there will be a good reason for those views.
"That paper says he's a corrupt politician; but we all know that paper's been a tacky tabloid since time immemorial."
That says nothing about the truth or falsity of the claim. It might mean it should be treated with caution, but it doesn't mean it can be assumed it's false.
That's when someone tries to convince someone, or decides, that they don't want to believe or approve of something, simply because people they wouldn't want to be associated with do, rather than because of any evidence.
"You're a Christian? But they're barbarians! Think of the Crusades and the Inquisition in the Middle Ages. And what about all the squabbling they do nowadays about which denomination is right? It's stupid. How can you possibly believe in Christianity after that?"
Since the fact people who've done things like that weren't doing them because they followed true Christian teaching, people who follow it won't necessarily think like them at all. So it's illogical to pour scorn on a person's beliefs not because of the beliefs themselves but because of who else claimed to believe them.
"You're an atheist?! That means you must approve of what Stalin did! He killed millions. You agree with Communism, do you?"
Atheism and Communism are not the same; just because Communists liked to promote atheism, it doesn't mean all atheists are Communists, just as the fact that some of the brutal dictators of the past have called themselves Christians doesn't mean all Christians are like them.
"What? Those sexist pigs are voting for him? I don't think I will after all then."
Someone running for office ought to be judged on their policies, not on who's voting for them. After all, just because a couple of 'sexist pigs' are voting for him, it doesn't necessarily mean he's one. It might, but that ought to be determined by what he stands for, not by who else is voting for him. The fact he has unsavoury supporters ought to possibly flag up a warning sign, but what if they're voting for him for a reason completely unrelated to what kind of person he is and what he stands for?
That's when someone draws a conclusion about a whole population or thing after discovering that a small sample of them are like that. In reality, some might be very different. It can be akin to prejudice. Or sometimes just laziness, where, for example, someone asks a few people questions, and concludes the entire town thinks like them. A much bigger percentage of a town's population would have to be surveyed before any conclusion about what everyone there thinks could be reached.
"Americans must be very rude. Did you hear what that one said to me?"
Not all Americans have the same attitudes and personality.
"Oh look. A black sheep. Sheep in this part of the country must be black."
There isn't nearly enough evidence to conclude that.
That's when someone assumes when one thing happens after another one, the first thing caused the second. It doesn't occur to the person that some other thing might have caused both. One example is that studies found that women taking a type of hormone replacement therapy had a lower than average incidence of heart disease. Some doctors at first thought it must be protective against heart disease. But scientific trials of it were carried out to test whether it really was, and it was found it actually caused a slight increase in the risk of heart disease. So the studies were looked at again, and it was found that women taking hormone replacement therapy tended to be from a higher social class, and tended to have a better diet and did more exercise. That was causing them to have a better chance of avoiding heart disease. It just so happened that they were also taking hormone replacement therapy.
There was also a study that found a relationship between children going to sleep with the light on in their bedroom and them developing near-sightedness in later life. The study concluded that sleeping with the light on caused it. It was reported in the press. But a later study was done that found that children who developed near-sightedness often had parents with the condition. It concluded that parents who had it were simply more likely to leave the light on in their children's rooms, so they could see them more easily. The reason the children got it was simply that it was a condition passed down from their parents.
Other examples include:
"Those new Baptist preachers must be stirring up hatred. Have you noticed that since the new churches were built and they've come along, there's more violence and drunkenness in the town centre at the weekend?"
If there's no evidence that the preachers really are the cause, then to assume they must be is illogical, especially when no other cause is looked for. It may be that a cause of both the new arrival of the preachers and the rise in drunken violence is a rise in the population of the town.
"The pine trees by the river are dying and loads of pine needles have fallen in the river. Now lots of fish are dying. It must be the pine needles killing them."
Or what if something else is killing both the trees and the fish, such as toxic effluent from the local chemical company flowing into the river? Maybe the pine needles have no effect on the fish whatsoever.
A moderate position between the extremes or compromise often will be the best thing. But not always. And if someone argues that it is, without any evidence to back their argument up, they are not being logical. For instance, if lawyers in court were arguing over whether a man was innocent or guilty of something terrible and worthy of decades in prison, it wouldn't be a fair suggestion to argue for resolving things by giving the man half the sentence. Examples of arguing for a compromise or moderate position without thinking things through first include:
"I wish you two wouldn't argue so much. You don't have to despise each other just because one wants the use of guns made even more lawful in America than it is and thinks they should be just as readily available in other countries, and one would like to see guns remain illegal in some European countries and banned in America. I mean, why don't we compromise? Why couldn't they legalise guns in those countries but only let people who were likely to need them most have them, like people in inner cities?"
In a situation like that, a compromise position could be just as disastrous as an extreme one, or more so.
"The government wants to cut some welfare benefits by 50% to save money in this time of austerity and to encourage people back to work. But the opposition wants to increase them by 10 % to keep up with the cost of living. I think a good way of resolving this would be a compromise, cutting payments by 30 %. That means it's somewhere in the middle of the two proposals."
So that's cutting people's welfare benefits despite the rise in the cost of living simply for the sake of compromise! Some kind of compromise might eventually have to be reached; but it shouldn't be reached just as a shortcut. Arguing out the various merits and drawbacks of trying to get people back to work by cutting benefits is one thing it's advisable to do before coming to a conclusion.
"We can't afford to send the thousands of troops they're asking us to send to the conflict. But we do want to please them, so we don't want to refuse to send any. Let's send a few hundred instead."
If that means the odds would be against them in a battle because there wouldn't be enough of them to ensure victory, compromising like that could again lead to disaster.
That's when someone thinks something's more risky than it is, and more risky than things it's actually safer than, because there's a dramatic news story about it or they've had a problem with it themselves. Something that goes dramatically wrong and is publicised is bound to imprint an impression of danger on people's minds. But being sure it's more dangerous than other things that are statistically far more dangerous than that is logically fallacious. An example includes:
"Those images of that train crash on television were horrible. I was upset by them. All those injured people. I'm going to stop travelling by train and travel by car from now on. Yes, I know you say that statistically you're far more likely to have a serious car accident than be in a train crash, but I can't believe that; train crashes are so nasty!"
It's understandable if people feel a bit fearful about going on a train after they've seen horrible images of an accident. After all, fear isn't a nice feeling, and if they think they're going to feel it when they get on a train, it's understandable if they don't want to. But unless they've got reason to believe the number of train crashes is going to increase quite a bit in the future, then ignoring the statistic about train travel being overall much much safer than car travel, and deciding car travel's safer, is not logical.
That's when instead of addressing a claim a person's just made, someone replies by just saying something abusive to or about them, as if they imagine doing that brings their claim into disrepute. Doing that can also be called Ad hominem abusive. Some people witnessing the conversation might imagine a person's claim has been brought into disrepute if they make it and then several people just ridicule them. They might think, "If they're that daft, how can anyone believe what they say?" But that would be just as much a logical fallacy as it would be for a person to verbally attack someone themselves and to think they themselves have done a good job of dismissing the claim the person's making. Just because someone says something bad about a person, it doesn't mean their claim can't be true. It might not be true; but just saying something abusive hardly proves that.
Personal attacks won't all be obviously nasty. Some can be more subtle, simply implying the person claiming something doesn't know what they're talking about, because of inexperience and so on.
Naturally not all claims people make deserve to be investigated or refuted with equal seriousness. For instance, if someone claimed that fairies organised the assassination of John F Kennedy, it would hardly be fair to expect people to treat that as a serious scholarly theory and investigate it to try to find evidence against it. Laughing at the person with the fairy theory and calling them daft wouldn't be an unreasonable response. Still, that wouldn't mean you were responding with logic. It would hardly be a logical rebuttal of the claim. That might be because the claim wasn't thought worthy of one. But if the person laughing thought they actually were rebutting it with logic, then they would be making a mistake. Rebutting it with logic would mean saying something like, "Fairies couldn't possibly organise a thing like that; they're allegedly so small they couldn't possibly have brains big enough to allow them to do the things they're alleged to be able to do."
Examples of substituting personal attack for evidence include:
"He criticises the government; but I, as a university professor, should think I know better than him, who's only just starting off as a student at university, and I think the government are doing a good job. Still, it was a good attempt at an argument, and I'm sure his arguments will get better as he learns."
Despite the fact he's only a new student, his claims might still be good ones. To say nothing about them, but to instead just try to discredit him as having a lack of knowledge, even while affecting a show of being nice, is to try to use a trick rather than logic.
"She believes drugs should be illegal, but she's just a goodie two-shoes Christian, so what she says on the subject isn't worth bothering about."
Anyone falling for such a dismissal of a claim certainly isn't falling for a logical argument. The argument has completely been avoided.
"Oh be quiet you conspiracy nut. Just how many other forums have you trolled with this stuff? I bet you live in your parents' basement and you never come out; you just sit there inventing silly fantasies all day."
Again, that says nothing about the claim itself. Even if ten people say things like that, it doesn't automatically make the claim nonsense.
That's like ad hominem but it means trying to destroy someone's credibility before they've even had a chance to make a claim, so people will be prejudiced against what they say when they do. Examples include:
"The man giving the lecture today once invited an extreme right winger to speak at the university. If he speaks against left wing ideas, you'll know why."
Anyone who lets that influence them could possibly read more into things than the lecturer actually says. And they might be so focused on looking for hints of sinister things that they don't take in what the lecturer's saying well so they won't get such a good understanding of their arguments. And after all, what if the lecturer invited the extreme right winger to speak so his ideas could be publicly debated and discredited? The lecturer could have some good ideas. Attacking him rather than his ideas is not logical.
"Don't trust anything he says. He believes the moon landings were a hoax. I mean really! How stupid can you get!"
That doesn't mean nothing he says will be correct. Trying to prejudice people against everything he might argue because of one of his beliefs isn't logical.
That's when someone tries to stop their opponent winning an argument not by putting forward a better one, but by saying something irrelevant which deceptively seems relevant in some way, to divert attention away from the subject so they can change it. Examples include:
"You've been arguing that public funding should be put aside to help the youth of this country, by arranging for youth clubs in each town to be started and extra programmes of education to begin. Actually I think we put aside a lot of money to deal with youth issues as it is. Do you know crime among the youth is very high in some parts? I don't think prison sentences are anywhere near long enough."
That's an attempt to change the subject. It might not necessarily be a deliberate one. But in any case, if it succeeds, the issue of putting aside public money to start youth clubs may just be forgotten.
"You say there's a new study that says a gene's been linked to major depression? Oh come on. Everyone knows depression's to do with bad life circumstances. I heard there was another study once that found depression costs the health service a huge amount. They give them antidepressants a lot of the time when they should be telling them to get help to sort their lives out. I heard someone on the radio say she felt depressed and had been taking antidepressants, and one day she went out and did some good exercise, and when she came back she felt so much better she threw all her antidepressants away, and never looked back. So even exercise can help."
The original claim might be totally forgotten about by the end of that, especially if people start talking about whether exercise is a substitute for antidepressants or get offended that anyone could suggest that just a bit of exercise could make depression go away just like that and get angry. The person saying those things has said nothing whatsoever that casts serious doubt on the claim that it's been found that there's a new gene linked to major depression.
That's when someone assumes, without any evidence to back up what they think, that doing one action will inevitably lead to another, and then another, and things will get worse and worse, so the first action shouldn't be done. It's not a fallacy if they can show logically how it's quite possible that that could happen. But it is a fallacy if they just warn that it will without feeling the need to support their claim with evidence. They might point to examples of times when things happened that led to worse things to try to show that bad things will happen again. But that will only be logical if there's a good reason to believe similar things will happen.
Examples of the slippery slope fallacy include:
"Don't do the lottery. If you get attracted to gambling, you'll want to take bigger and bigger risks, till you're gambling with far more of your money than you can afford and you might even turn to crime to support your habit."
That does happen to some people; but since they're in a small minority, the person needs to show why there's a special reason why it's likely to happen to the person they're talking to. If they can't, and assume it'll happen to everyone, then they are ignoring a lot of evidence, so they are being illogical.
"If the government brings in a law allowing euthanasia, it won't be long before people are allowed to kill off their grandparents just because they're a nuisance. We can't allow them to make mercy killing legal."
There doesn't seem to be a good reason why one thing should lead to another; and unless the person can give convincing evidence as to why it might, then they are being illogical in thinking it will.
That's where someone thinks a certain rule, standard or principle applies to everyone else, but, for no good reason, thinks it doesn't have to apply to them. Examples include:
"Yes I know I've been preaching against adultery for the past twenty years, calling down hellfire on adulterers, warning them of eternal punishment. But ... well, ... she and I love each other. And I was unhappy in my marriage and so was she. What we have is a beautiful thing. But yes, I still believe most adulterers will suffer eternal torment."
Most people who have affairs might be able to justify themselves by saying they were unhappy and they love the person they're having an affair with. There's no logical reason at all why any one of them should hold the rest to high standards while they don't feel the need to hold to them themselves.
"No, constable, I don't approve of speeding at all. It's a despicable habit. But it's been a long day. I'm tired. And there's a great television programme on I really want to get home for. Please let me off, just this once."
Most people will think they have reasons for speeding. Many people coming home from work will be tired and looking forward to getting home. If speeding's wrong when they do it, there's no reason why it shouldn't be for the person who's just been caught.
That's where someone assumes without thinking that people or things that get a lot of attention in the media spotlight are just like everyone or everything in the group they're associated with. So they stereotype the people or things in the group because of what they've heard or read. In reality, it's the unusual things that normally get most media attention.
"I'm never going to America. It's full of crime and violence. And people shout and swear all the time. It would be far too dangerous and I wouldn't want to be around all those abusive people."
The things reported in the papers are the dramatic things that make the news; and films show dramatic things because their makers want to make them exciting and interesting. They're not representative of the way everybody is.
"You seem a decent young person. I can't believe you went to school around here. I read so much in the papers about violent and promiscuous teenagers nowadays; you're not like that at all. You must have been raised in a convent school. I just can't believe you're a normal teenager."
Using the papers as a source of general knowledge on the habits of any group, and then finding it difficult to believe any members of the group could be any different, is not a logical way of thinking, since the papers like to report the most sensational things and ignore anything that would be boring to report on.
That's when people think that if they've had an unusual run of good or bad fortune or just a string of similar results, things will have to change soon. It's not a fallacy if they think things will change because on the balance of probabilities, things aren't likely to stay that way for that much longer. But it is one if they haven't got a good reason for thinking it. For instance, if they've lost three card games in a row, there isn't any good reason why they should win the next, especially if the game depends partly on skill and they're not that skilled. But they might feel sure that their luck just has to change soon.
Other examples include:
"Yes, I've lost six boxing matches in a row, but my bad luck can't go on forever. I reckon I'm due a win now! In fact I'm so confident I'd even recommend you bet on me to win."
It isn't just luck that depends whether people win or lose. A lot will have to do with the skill levels of the person and their opponents. And besides, when it comes to small numbers of things, streaks of the same things happening can happen even just by chance. They don't correct themselves to make things even.
"This horse hasn't won all week, but the form books say he won in half his races last year. With that form, he's due for a win! I'm going to bet my wages on him!"
What if he's slightly injured or in a little pain? What if he's been drugged by some corrupt official trying to fix the race? It isn't just probability that determines how bad or good his form will be.
That's where a group of people who aren't representative of a population as a whole are used to draw a conclusion about the whole of that population, as if they're just the same as people who are different.
It doesn't just apply to people; it can be anything. For instance, if someone buys a basket of strawberries in the market, they might look at the ones at the top, think they're really nice, and take the strawberries home, assuming they're all like that. But the ones at the top might be an unrepresentative sample. The ones at the bottom might be all rotten.
An unrepresentative sample of people might be the result of a mistake in gathering information. For instance, if an organisation's doing an opinion poll asking people whether they have children, and they're standing outside a shop that sells toys and clothes for babies taking the poll, most people they approach and ask the question might well be people just going into or coming out of the shop who do have children and that's why they're there. So the poll might end up concluding that more people have children than really do, because the sample of people they used was more likely to have children than a sample of the public who were asked somewhere else would. A sample of the public taken elsewhere in the neighbourhood might be far more representative of the public in general.
To give some other examples of how samples of people chosen from the public to take part in a poll can be unrepresentative of the public, and how it's a logical fallacy to claim they're representative:
"We wanted to find out who'd win the election. We polled 100 people from all over this council estate and it's obvious the Labour party's going to sweep to power."
People on a council estate might be far more likely to vote Labour than other sections of the public, so to just poll them and claim it's possible to tell how the whole public's going to vote all over the country is a logical fallacy.
"Alfred Kinsey claimed that one in ten men are gay, so it must be true. After all, he was a qualified sex researcher."
Just because someone's qualified in something, especially when it's a questionable field, they aren't necessarily going to provide trustworthy enough findings for anyone to be absolutely certain of them. As a matter of fact, Alfred Kinsey's reports on the sexual habits of American men in the years after the Second World War were rather flawed. He only interviewed a small number of men, but from those, he imagined he could draw conclusions about the sexual habits of the entire male population. He concluded that one in ten men was gay, one in two had cheated on his wife, and one in six had either been victimised by or had victimised another family member sexually. Research into the people he polled found that there were far many more men from prisons than would be found among the general public, and also a significant number of male prostitutes. Also, some people had volunteered to take the survey rather than being randomly asked, and it can often be that many of those who volunteer to take a survey have an issue with something.
To give an example of something else rather than humans, it was reported that once when Puerto Rico was hit by a hurricane, there were ten thousand claims by residents for hurricane damage. The US Government decided to calculate the amount of aid it gave by adding up the amounts of money claimed in the first hundred claims and multiplying by a hundred, to get the rough amount they assumed would be claimed in ten thousand of them. Someone was involved in the "difficult task" of persuading the US government that the first hundred applications wouldn't necessarily be the same as the rest. Small claims are likely to come in first because they need less preparation.
This article is part of a series on self-improvement on this website, which mostly features articles on overcoming conflict in marriages and with others, recovering from emotional problems such as depression and anxiety, and coping with other difficult life situations. To see what's in it, Go to the list of articles.