Every Single Logical Fallacy Explained

0:00 this video is sponsored by Squarespace more about them in just a moment logical fallacies are a hot button topic every year there are videos that go viral all across YouTube explaining the top 10 logical fallacies or the best logical fallacies and how to spot and disprove them and these are all well and good but I want to do something a little bit different I want to propose a framework that moves Beyond simply identifying logical fallacies and instead sees why they are such poor arguments and gives you a way to spot bad debating even when you can't explicitly name the logical fallacy involved so rather than listing fallacies one by one I'm going to break them down into types and then argue why

0:47 I think this is a more productive and ultimately much more helpful way of viewing logical fallacies these types certainly won't be exclusive or exhaustive and some fallacies will definitely fall into more than one category but I do encourage you to build upon and improve my framework for your own personal use this is also something of a sequel to a video I made a long time ago about logical fallacies and it will cover some of the same material but there's also plenty of new stuff so if you've seen that one you will still get a lot from this one by the end of this video I hope that you won't even need to use these named fallacy labels at all but let's begin with the easiest kind of fallacy to Define and step into one of

1:32 my favorite topics formal logic but before moving on I want to take a brief moment to thank today's very kind sponsor Squarespace if you're looking to build a website then you know it can be a real pain first you have to choose a domain name and then design the whole thing and there's always this underlying worry that you're messing up and creating something that's not just messy but actually looks downright unprofessional but this is where Squarespace comes into play they compress all of that complexity into a single platform and use ready-made templates to take all of that headache out of website building they also have a feature called design intelligence which uses AI tools to help you make design choices which is really handy if like me you don't have the mind of a graphic designer and don't necessarily have a an

2:19 eye for visual arts to put it incredibly gently head to squarespace.com for/ unlisted advice and use the code unlisted advice to get 10% off your first purchase of website or a domain name thanks again to Squarespace for sponsoring this video and let's get back to it one formal approaches the word logic is used in a surprising number of ways from denoting particular systems to just meaning thinking well when I was at University I mainly studied formal logic which is a type of language designed to establish which premises imply which conclusions in other words what we can infer from what that sounds a bit abstract but we've all encountered this sort of thing in its basic form take the following argument one all men are

3:06 mortal two Socrates is a man three therefore Socrates is Mortal everyone can recognize that this is a good argument but more than that it is valid that is if all of its premises are true its conclusion cannot be false if all men are mortal and Socrates is a man then Socrates just must be mortal this is because the argument has the following valid logical structure one for any x if x is f then X is G two a is f three therefore a is G formal logical systems set certain rules which dictate which moves in an argument are valid and which are not that is which preserve truth and which allow for mistakes to

3:52 creep in these rules can vary between different logical systems for example while classical logic states that any statement must be true or false and there is no in between in three valued Logics there is truth falsity and some third thing which often stands in for something like I'm not sure so whereas In classical Logic the argument structure one not not a to therefore a is valid in many three valued Logics it is not classical formal logic provides one very neat framework with which to look at many logical fallacies for all the sway they hold in popular discourse most logicians don't really talk about particular logical fallacies but simply identify whether a given argument or proof is valid or not some fallacies

4:39 just use an invalid argument structure like the following one if Socrates were here then people would be angry two Socrates is not here three therefore people will not be angry this argument looks almost exactly like a valid logical structure called a modus ponent argument where if a implies b and a is true then B must also be true however the actual structure of this argument is if a implies b and a is false then B must also be false but this simply doesn't follow we can clearly see this in our example even if Socrates were not there irritating everyone with his incessant questioning people could still be angry they just have to be angry at something else like the weather or a substandard pot of tea this fallacy is

5:27 known as denying the antecedent as we said it's a mistake in logical structure it is perfectly possible that all of the premises would be true and the conclusion would still be false it is invalid if we were being technical then every fallacy of logical structure is just an example of the non sequor fallacy this is Latin for it doesn't follow and it identifies an argument as invalid this is why if logicians are criticizing an argument they will tend to say this doesn't imply what you think it does or this argument step is invalid rather than pointing to a specific named logical fallacy it's worth noting a good number of fallacies do fall into this category let's call them Loosely fallacies of form for example the fallacy of composition is when you infer

6:13 something about the whole set or collection of objects from properties about the objects themselves the fallacy of composition is quite interesting because sometimes it actually does get you to the right conclusion but its structure does not guarantee that you will find the right conclusion for example here is a solid argument that still technically uses the fallacy of composition one every part of this house is made of Lego two therefore the house is made of Lego the general structure of this argument is every X in collection y holds property F so the collection itself holds property F however we can immediately see that this isn't always the case for example one every brick in

6:58 this wall is under 30 cm long two therefore the wall is under 30 cm long in both cases the form of the argument is facius but in the first argument it still worked because it just so happens that if all the parts of something are made of a certain material then the whole thing is also made of that material this doesn't hold for properties like length or shape and so the general argument scheme cannot be relied upon we must assume some auxiliary premise to make it work and this illustrates another General Point that's going to become incredibly key in this video just because an argument is fallacious it doesn't mean that the conclusion is definitely not true this is especially the case when it comes to formal fallacies because validity is an incredibly High bar to jump over it

7:45 means there is no possibility where the conclusion is false provided that all the premises are true for example the following is a really quite persuasive argument and most people would say it is in some sense good but it is still definitely not valid one every morning so far the Sun has risen two therefore the sun rises every morning of course this is a perfectly normal inductive argument yet it is technically invalid because it is possible that even though the sun has risen every morning for billions of years it will stop Rising tomorrow through some unpredictable change logical validity is not the be all and end all when it comes to argumentation Additionally the second property of an

8:32 argument that logicians are often interested in is soundness this term is used in a couple of different ways sometimes it means the premises of the argument are true and sometimes it means the premises of the argument are true and the argument is valid most people use the second definition even though I think the first is more helpful because it allows you to talk about the truth of the premises and the validity of the argument entirely separately but my personal quibbles aside essentially if an argument is valid then the next question to ask is are all the assumptions of the argument true this is because if they are then the conclusion must also be true and we have an airtight case for that conclusion then it's happy days because we can all go home and the argument is put to rest for our current purposes we can analyze some

9:18 logical fallacies as having an obviously unsound premise or obviously unsound premises for example take a classic ad homonym attack imagine that two politicians are having a public debate and one of them turns to the other and says but you're a bad person so your policies will run this country into the ground we could represent that argument in propositional form as follows one you are a bad person two policies put forward by bad people will run countries Into The Ground Three Therefore your policies will run this country into the ground the trouble is the second premise of this argument is just false policies have merits independent from the people putting them forward it could be that a truly immoral person nonetheless has far

10:06 more economic or political Acumen than their opponents likewise someone who was extremely personally moral could be an outright incompetent leader what is true and what policies make sense have nothing to do with the people who' proposed them however it gets complicated since despite the arguments unsoundness most people do want to know their leader personal moral character when voting for them and we don't tend to think that they are wrong to do so whether this particular argument is unsound depends on which conclusion is actually being argued for political rhetoric often means people exaggerate the strength or form of their conclusions if the politician instead turned to the audience and said my opponent is morally bad so you should not trust them to make policies in your

10:52 interests the situation changes entirely then we have the following argument one my opponent is a bad person two you can't trust bad people to make good policies three therefore you can't trust my opponent to make good policies at the very least the second premise here is much more plausible it is not so obviously unsound that we would want to dismiss it as fallacious after all politicians can enrich themselves while in office and they can make policies that are not in the interests of the people they're governing and this may be more common if the politician themselves doesn't have a strong personal moral compass we can make SAR observations about appeals to Authority if someone is saying a leading expert has said this so it is true that relies on the false idea

11:37 that whatever a leading expert says simply must be true but of course leading experts are wrong all the time and mistakes are part of how Collective expertise progresses one of the greatest mathematicians of the early 20th century David Hilbert believe that mathematics would be reducible to a complete and consistent logical system and he was definitely proven Wrong by girdle however it's also clear that appeals to Authority are not always fallacious for example imagine that myself and a friend are having a discussion about the science of batteries however neither of us know very much about the science of batteries in this case appealing to what an expert thinks or expert consensus is a pretty decent proxy measure for Reliable belief formation experts can

12:24 certainly be wrong but if we personally don't know that much about a topic then they're often what we have to go on it can provide defeasible evidence for a particular conclusion and put a pin in this importance of context when evaluating logical fallacies as it's going to be the focus of the third section of this video considerations like this mean that while formal approaches to logical fallacies are fantastic in a whole host of ways and I think that if everyone learned basic propositional logic the world would be a much better place they don't do justice to the full complexity of argumentation for one thing contextual factors like the prior knowledge of the arguers and the strength with which a particular conclusion is put forward seem highly relevant to where a given argument is facius or not and this isn't necessarily

13:10 captured neatly by just using formal systems another way of looking at matters might be more convenient or more practical moreover there are fallacies like the no true Scotsman fallacy and the burden of proof fallacy and the straw man fallacy which are not to do with soundness and validity but something a little bit more nebulous and as a result the formal approach can't quite capture this so as much as it pains my heart to do so we must descend from the platonic realm of logical laws to the messy business of real world argumentation and step into a fascinating recent field of philosophy called informal logic two the argument game in Ludi Vicken Stein's postly published Works he gave one of the most

13:57 famous analyses of language in history that went on to influence computer science Linguistics philosophy psychology and more whereas many traditional theories of language tended to focus on the semantic content of statements and the pure logical relations between them Vicken Stein's later works were much more concerned about what language does and the different purposes it conserve he called these purposeful ways of using language language games and similar to other types of games they have certain rules and certain expectations just like how when you're playing chess there are appropriate ways to move the pieces and inappropriate ones there are ways to get conversations wrong so to speak some of these language games are very obvious and have very obvious rules like a

14:43 cross-examination in a court of law where there are explicitly defined constraints on what can and cannot be said and someone actively enforcing those constraints at the time but some games are much more subtle for example The Language game of standup comedy allows people to say false statements as long as they are funny enough whereas The Language game of a PhD vior does not give this leeway so one way to look at this larger class of logical fallacies that are not captured by formal logic is to ask what are the rules of the argumentative language game and do these wider logical fallacies break them in recent years many philosophers have tackled this question one highly influential analysis comes from Douglas Walton and says that in a standard argument each person aims to persuade

15:30 the other person while at the same time getting to the truth of the matter as much as possible according to Walton the implicit rules of this language game assume that each person genuinely wants to persuade their opponents to their point of view and to understand why they disagree he asks us to picture the dialogue as two agents Each of which hold conflicting conclusions and a set of prior commitments that led to those conclusions that is what they already believe to give you a flavor I'll outline just some of his explicit rules one arguments against the opponent must assume the opponent's commitments two both sides must honestly represent both their commitments and their opponents and not change their commitments without explicitly saying so three each person

16:15 must answer reasonable questions from the other side four no one can declare definitive victory until the other side's position is untenable or has been explicitly conceded five in general arguments should appeal mainly to the opponent's reason these are just a general sketch of Walton's rules of argumentation they are not exhaustive because what seems appropriate in an argument will vary slightly from situation to situation and is not really reducible to a finite set of laws but a good overall question to ask is this is each person honestly searching for the truth and to persuade one another on that basis or do they seem like they're doing something else if they're doing something else then Walton thinks they are implicitly breaking the rules of

17:01 argument in my last video on logical fallacies I called this sort of thing Bad Manners but the framework of informal logic provides a much more precise way of dealing with them incidentally that video ended up getting restricted for sexual content I could have sworn that I didn't but perhaps I was wrong either way a few examples will help illustrate why this way of looking at fallacies can sometimes be helpful take the no true Scotsman fallacy this is where someone suddenly shifts their definitions in order to defend a point say for the sake of argument we were debating whether philosophers made good lovers you pointed to a number of philosophers who either were or would make very poor lovers say n shophow and the numerous monastic thinkers throughout history but

17:48 I then reply aha but they must have not been true philosophers any true philosopher is a phenomenal lover this is a classic example of the no true Scotsman fallacy I am changing my definition on the fly to reply to a counter example the thing is there is nothing logically wrong with this logic cannot dictate definitions and if I suddenly want to Define philosopher in a weird and wonderful way there is no logic police who will come to my house and handcuff me to my radiator formal logic can only kick in once definitions have already been established but no true Scotsman still breaks a key rule of argumentation it is dis honestly shifting my position without explicitly conceding this to my opponent it means I

18:33 am no longer arguing honestly but attempting to obscure what my true conclusion and my true beliefs are the same goes for the mot and Bailey fallacy this is where an arguer has two positions which they shift between at will the mot is usually an eminently sensible and defensible position but one that is much more modest whereas the Bailey is a far more extreme position that is taken whenever the argu is not being directly challenged to use my normal outlandish example imagine that I am the leader of the puppy hating party of Great Britain and Northern Island and I want to argue for the complete eradication of puppies I know that my position is highly unpopular so I conceal it using a Mot and Bailey fallacy my mot is I'm just letting

19:21 people know that some of these puppies will inevitably bite people when they grow up and my Bailey is all puppies must be proactively disposed of whenever someone challenges my second extreme position by pointing out that most puppies will grow up to be harmless I can then say I know that most puppies are harmless I'm just telling people that some will inevitably bite when they are fully grown again there is nothing in formal logic that prevents me from doing this but I'm not being honest about my position and so I'm falling a foul of the argumentative rules then there are burden of proof fallacies this is where I unjustly try to make someone else bear the burden of proof when it truly rests with me for instance if I

20:09 were arguing that goblins control the weather and someone else asked me to produce proof and I simply said well you can't prove that goblins don't control the weather I am trying to make the opponents take up the burden of proof when I'm the one making a novel and unusual claim it's not always the person making a positive claim who has the burden of proof if I'm defending the idea that the Earth revolves around the Sun and someone else simply wants to say it's false that the Earth revolves around the Sun then they're making a negative claim and I'm making a positive one but they still have the burden of proof because the generally accepted position is heliocentrism this doesn't by itself mean that heliocentrism is correct but it does mean that if the goal of an argument is to persuade people it

20:55 definitely requires disproving rather than the burden beginning of on the HELOC Centrist so to speak the strawman fallacy is also not against any rules of formal logic logic deals with relationships between propositions and nowhere does it say that you cannot completely parody your opponent's position in the process but it does go against the rules of argumentation outlined here it is dishonestly representing your opponent standpoint and as a result it is an informal fallacy but believe it or not things get even more complicated because despite the fruitfulness of this approach we can't simply lay down a set of laws and say that anything that breaks them is a fallacy for many supposed fallacies whether or not they are actually felicious is highly dependent on context

21:41 but luckily this is just our next point if you want to help me make more videos like this then please consider becoming one of my wonderful patrons the link is in the description three contextual fallacies imagine for a moment that I am a lawyer arguing that my client should be given a lighter sentence than usual for his crimes I talk about how he grew up in a broken home how a gang took him under their wing and how he only committed this crime because he was starving won't you take pity on this man I said here is my question is what I'm doing felicious or not it is clearly an appeal to pity which is normally seen as a fallacy but whether it is outright fallacious seems to depend on a further question whether the pity is warranted

22:29 this example is also from Walton's work and it fantastically illustrates the importance of context when we're discussing fallacies for instance imagine the crime committed was stealing a loaf of bread and the situation was all very Jean Balan in this case most people think that the appeal to pity would be somewhat appropriate since most think petty theft is less worthy of condemnation when it is committed out of desperation however if the man was guilty of a triple homicide then most think the appeal to pity is now entirely inappropriate you can't try and make us feel pity now we want to say you have already done the near unforgivable Walton argues that whether the appeal to pity is fallacious or not cannot be established by simply looking at the argument we must also look at the

23:16 context in which the argument is given and he is not the only one the same point is made by Christopher Tindale and has become mainstream among informal logic Scholars another pretty good example of contextual importance is the ad homonym attack we looked at earlier there the contextual Factor was what specifically the politician was arguing for if they were arguing that bad people necessarily make bad politics then they would commit a fallacy if they were instead arguing that bad people are less trustworthy and this is pretty important if you're going to be in a position to empower yourself at the cost of your nation then the ad homonym attack is no longer irrelevant but is pretty important it seems like that's a pretty good thing to know attacking someone's person in a debate is only fallacious if

24:02 their character is not actually pertinent to the issue at hand Beyond these more obvious contextual factors conclusions can be argued for at different strengths in practice we don't just believe things wholeheartedly or reject them outright we believe things to a given degree of confidence we might also not believe in something but just think it's plausible or believe in something while recognizing that it is only probable and not definitive and this has a real bearing on whether a given argument is felicious or not this is again pretty evident with an appeal to Authority for example if I were arguing that the Earth was flat and you pointed out that almost every expert on the topic agrees that the Earth is not flat this does not refute any of my flat Earth arguments directly however it will

24:49 be enough to throw doubt upon the conclusion shift the burden of proof in my direction and warrant further investigation on my part say the recent South Pole experiments which demonstrated that the Earth was definitely not flat or any of the other numerous experiments along the same lines the appeal to Authority was justified for a particular conclusion establishing the definite uncertainty of the Flat Earth hypothesis then this allowed for further investigation revealing that the Earth was not flat context is especially important when thinking about inductive arguments some fallacies like the slippery slope fallacy depend almost entirely on where whether there is sufficient evidence for the slippery slope in question for instance when debating whether euthanasia should be legalized in a

25:36 given country people tend to point to where euthanasia laws have gradually expanded from just applying to painful terminal illnesses to more and more cases such as non-terminal conditions and mental illnesses when this is brought up some people accuse it of being a slippery slope fallacy but that depends on one to what extent these expansions have actually happened and two whether the new country's legal system is sufficiently similar to those other countries that the expansion might plausibly happen there too it also depends on how strongly the conclusion is argued for if the arguer thinks the slippery slope will definitely happen then that is fallacious no inductive reasoning can justify such claims whereas if they're simply saying that this evidence makes it more probable

26:21 that the slippery slope will occur then that is not fallacious but a standard application of inductive reasoning again this is all assuming that their premises are correct similarly some standardly fallacious arguments can't prove anything is true but they can shift the burden of proof in some contexts this is often the case for the argumentum ad populum or the appeal to popular opinion if the majority of people woke up tomorrow believing that the sky was green that would certainly not make it green but it would mean that it's plausibly on us to convince them otherwise this is because if we assume that the goal of our argument is to persuade then in this case persuading the most people requires refuting their beliefs and in this case positively

27:07 arguing that the sky is not green here the justification for moving the burden of proof is practical rather than philosophical though this too will vary from Context to context a publicly elected politician has to care a lot more about what the majority thinks than an academic who will largely pay attention to academic consensus the textual factors just never end sometimes what counts as fallacious depends on pretty wide- ranging philosophical beliefs like what is right and wrong this is clearest with the argumentum ad baculum or the argument from force a classic example of this is believe what I do or I will hurt you at one level this is an unsound argument because no amount of force will make a false proposition true but sometimes warning

27:55 of consequences is perfectly reasonable for example if you're about to steal a car I might say you shouldn't do that you'll go to prison here I'm assuming that you want to act in your own best interests and I'm reminding you of the likely consequences of your actions this differs from a direct threat because I'm not going to send you to prison myself and also because most people see it as just for car thieves to be punished for their actions If instead we were in the world of 1984 and a thought police agent said you should say that you'll go to prison this seems closer to a fallacy because the law in question strikes us as unjust these numerous contextual factors add pretty significant complication to our definitions of

28:41 fallacies because it means we can no longer identify most fallacies simply by their structure or their appearance we can't label every time someone references an expert as an appeal to Authority fallacy and we can't dismiss every appeal to emotion as straightforwardly fallacious we need to ask what context the argument took place in and what the arguer is actually trying to prove the world of argumentation is far broader than simply formal logic or even the rules we outlined in the previous section identifying fallacies in practice requires what Aristotle called fris or practical wisdom it means taking into account a wide variety of factors incorporating formal logic context and the implicit rules of persuasion to

29:27 evaluate the extent to which any given argument is committing one or more fallacies but then this raises an important further question if there's all this complication to logical fallacies then what's the point of criticizing arguments using these terms and I would say there actually isn't much Point Beyond simply convenience and that we would do well to expand our Horizons here four Beyond logic and fallacies perhaps my favorite named fallacy is the fallacy fallacy this is where someone uses logical fallacies a bit like a magic spell as if merely speaking their name is enough to dismiss someone's argument and furthermore treat their conclusion as false the best

30:13 demonstration I found of this magic spell use of fallacies is actually in a meme by original P 6209 here we have an exchange between two people one is a stereotypical Chad and the other a sort of car of an unintelligent person the Chad is using fallacy labels to convince the other person to give him their wallet illustrating just how unhelpful this little argumentative name calling can sometimes be here saying imagine if I asked for your bank details is changing the subject of the debate but it's doing so in a relevant way it is challenging the Chad to show that their demands can be justified to some external third party and that they're not just making a self-interested demand we can imagine situations where the Chad

31:00 actually has a good response imagine that he's investigating the other person on suspicion of murder and he wants to use the wallet as evidence then he could say these two situations are not the same I am confiscating your wallet for public benefit and if I were under investigation for murder then my wallet could also be taken as we've already discussed sometimes so-called fallacies are simply imperfect arguments rather than ones that deserve outright dismissal if I'm having a debate and someone makes an appeal to Authority fallacy suggesting that whatever the expert consensus is must be true then sure they have made a mistake but it would also be a mistake for me to ignore expert opinion if I know far less about

31:45 the topic then expert consensus is definitely worth listening to it's just not worth taking as gospel my opponent has actually told me something very valuable here and if I'm arguing in good faith and search for truth then I would ask although this person has presented the argument in a FCI way what does it actually imply another way of posing this question is what is the Justified warrant of the facius argument that is what useful information does the facius reasoning still contain sometimes this just won't be very much if someone argues that I am wrong because I have curly hair and curlyhair people can never be right then I haven't really learned anything other than that my opponent does not like curly hair but if

32:32 they were appealing to majority opinion on the matter then that does tell me something it means that either most people are wrong or there might be some flaw in my own position of course it could be that they are all wrong but it does encourage me to reexamine my argument it SWS just that little bit of doubt and justifies a measure of epistemic humility here instead of just pointing out the fallacy in being done with things we are noting what the opponent's premises actually do imply of course this may not be a very good rhetorical strategy but it is a much more nuanced way of thinking about fallacies themselves because it tells you where your opponents might actually have a point even if they can't express that point properly now we are not just

33:18 considering the opponent's argument and their conclusion but also their premises in isolation to see what they demonstrate by themselves it is in effect a principle of Charity that allows us to Steelman our opponent's position if you wanted to go one step further another question you could ask is what would it take for my opponents to be correct this allows you to see not just where they go wrong but also what it would take for their argument to become persuasive for example if my opponent is overplaying their hand with an unjustified slippery slope argument it's worth asking how much further Evidence would be needed before their point becomes highly Justified and in fact incredibly persuasive circumstances change all the time and by using this

34:04 approach our beliefs will change along with them rather than becoming calcified and dogmatic I also think that the named fallacy approach has some disadvantages beyond the tendency to assume that the conclusion is false just because the argument in its favor is fallacious it also encourages this incurious attitude to debate where we're simply trying to find ways to dismiss an opponent's position rather than take anything from it ourselves and potentially improve our stock of true beliefs additionally given the considerations from the last couple of sections pointing to particular fallacies can often be unhelpful for appreciating what has actually gone wrong in a particular argument if not all personal attacks are at homonym

34:50 fallacies and not all slippery slope arguments are fallacious then we may obscure What's Happening by attempting to pigeonhole these arguments based on surface level features so I would propose a slightly different approach instead of reaching for fallacy labels we can ask a series of questions to evaluate almost any argument that's thrown our way one is this argument valid two are there any obviously unsound premises three are they acting as if they want an honest discussion of ideas or have they Fallen a foul of an argumentative rule four with what strength is the conclusion being argued for plausibility probability proof or something else five what level of

35:36 strength do the premises actually give to the conclusion does it match the arguer intention or have they overplayed their hand six what have your opponents premises shown if they are true regardless of their intention do you need to adjust your argument or your beliefs on this basis and seven under what circumstances would your opponent's argument be correct of course this is just my model and it's very much open to Improvement or adjustments depending on its flaws and your individual needs but I hope it is some help in taking you through the process of both identifying what is wrong with a fallacious argument but also what might be learned from it regardless because while it can be

36:23 satisfying to Simply hurl a fallacy at someone this way I'm reasonably confident that you'll be able to take something new from almost every argument you encounter even and perhaps especially the bad ones but if you want to learn more about the kinds of questions that promote sound critical thinking then I have a video on socrates's very famous questioning model right here thank you so much for watching and have a wonderful day