{"id":167,"date":"2006-04-04T12:26:14","date_gmt":"2006-04-04T16:26:14","guid":{"rendered":"http:\/\/thenonsequitur.com\/?page_id=167"},"modified":"2017-01-25T13:30:58","modified_gmt":"2017-01-25T18:30:58","slug":"informal-fallacies","status":"publish","type":"page","link":"https:\/\/thenonsequitur.com\/?page_id=167","title":{"rendered":"What’s a non sequitur?"},"content":{"rendered":"

Special note: we’re in the process of rewriting this page–if you think we ought to add anything, or if you think we ought to clarify something, or you have fun examples of any of the fallacies you’d like to share, please don’t hesitate to let us know in the comments below.<\/em><\/p>\n

What’s a non sequitur?<\/strong><\/p>\n

In Latin, a dead language in nearly every respect save portentous phrases like salva veritate<\/em> and names of important philosophical notions, the phrase non sequitur<\/em><\/strong> literally means “it does not follow.”\u00c2\u00a0 What “does not follow” is the conclusion<\/em> from the premises<\/em> of an argument.\u00c2\u00a0 When that happened, in ancient Rome and in the Middle Ages, people would scream “non sequitur!”\u00c2\u00a0 In a broader sense, a non sequitur is a logical fallacy<\/strong>, from the Latin fallacia,<\/em> meaning “trick.”\u00c2\u00a0 So a fallacy is a kind of trick, a logical trick.\u00c2\u00a0 Yet another term for a logical trick is sophism<\/strong>, which recalls the ancient Greek Sophists, famous for their dishonest argumentative trickery.<\/p>\n

Reasoning fallaciously is something like cheating or stealing. You attempt to acquire something that you have not earned or paid for. Unlike cheating however, when one reasons fallaciously one does not, despite appearances to the contrary, actually acquire anything.\u00c2\u00a0 After all, the whole point of argument is proof<\/em>–if your proof fails, you don’t earn your conclusion–even if some people think you do.\u00c2\u00a0 Your conclusion may turn out to be true independently of your argument, but that doesn’t make your reasoning good.\u00c2\u00a0 It just makes you lucky.\u00c2\u00a0 The cheater may be a better athlete, but that doesn’t mean the cheater deserves to win by cheating.<\/p>\n

Very roughly then (as we have at this moment no stable theory) a fallacy is a systematic and egregious defect in an argument.\u00c2\u00a0 To continue the cheating analogy, we might liken a fallacy to a penalty in a football game.\u00c2\u00a0 Penalties are the typical ways one tries to break the rules (i.e., to cheat)–offsides, holding, face masking, etc.\u00c2\u00a0 There are certainly more ways to violate the rules than these, and determining which penalty has been committed sometimes involves a great deal of interpretation on the part of the referee, but the general concept is clear to anyone who knows about football.\u00c2\u00a0 As it’s possible to group football penalties into categories, it’s also possible to group informal fallacies into categories.\u00c2\u00a0 As football offensive lineman are prone to holding, ideologically driven arguers will tend to distort (straw man–see below) their opponents’ arguments in order to “win.”<\/p>\n

But we think the analogy to football ends there.\u00c2\u00a0 Dealing with fallacies isn’t like the referee’s hand motions in a football game.\u00c2\u00a0 It involves–or rather should involve–some explanation.\u00c2\u00a0 Nothing annoys us more, in fact, than people who scream the fallacy name without offering any accompanying analysis.\u00c2\u00a0 For us it’s the analysis that’s important.\u00c2\u00a0 The name is just a kind of shorthand placeholder for the general problem.<\/p>\n

What are the fallacies?<\/strong><\/p>\n

There are two basic types of fallacy–formal<\/strong> and informal<\/strong>.\u00c2\u00a0 A formal fallacy<\/strong> is a systematic defect in deductive reasoning.\u00c2\u00a0 Here’s an example of one:<\/p>\n

Since all dogs are animals and all cats are animals, it follows that all cats are dogs.<\/p><\/blockquote>\n

The problem here is the formal fallacy of the undistributed middle.\u00c2\u00a0 The defect concerns the logical form of the argument, not the content of the propositions.\u00c2\u00a0 For a more detailed discussion of formal fallacies, click here (page not up yet).<\/p>\n

By contrast, informal fallacies<\/strong> regard the content.\u00c2\u00a0 An informal fallacy is a systematic and diagnosable defect in inductive (broadly speaking, non-deductive) reasoning.\u00c2\u00a0 It usually involves some kind of distortion of the content of the argument.\u00c2\u00a0 These may be distortions of relevance, probative force, or meaning for instance.\u00c2\u00a0 Aristotle, the first to engage in the systematic study of fallacies, identified 13 different fallacies in his On Sophistical Refutations<\/em>.\u00c2\u00a0 For those click here<\/a>. \u00c2\u00a0 Nowadays informal reasoning texts tend to present anywhere from 18 to 25.\u00c2\u00a0 Some scholars have identified many more.\u00c2\u00a0 Here are two examples: one<\/a> and two<\/a>.<\/p>\n

Following a lot of informal logic texts and for the sake of simplicity we group the the informal fallacies into three basic categories–fallacies of relevance, fallacies of weak induction (or fallacies of evidence) and fallacies of presumption and ambiguity.\u00c2\u00a0 These correspond to the three typical types of distortion in informal reasoning: distortion of relevance, of evidence strength or probative force, and distortions of meaning.<\/p>\n

The following is a list of the fallacies one is likely to run across in every day arguments found in op-ed pages and elsewhere.\u00c2\u00a0 As time permits, we will add somewhat cartoonish examples of the fallacies for the sake of the curious public.\u00c2\u00a0 The egregiousness of the examples shouldn’t be viewed however as a claim that all instances of fallacies in everyday life will be similarly absurd and egregious (and consequently that any non-cartoonish instance of a fallacy which we point out is a failure of charity on our part).\u00c2\u00a0 They usually won’t be so silly.\u00c2\u00a0 Their lack of silliness, in fact, is the reason they are called “fallacies”–they’re deceptions.\u00c2\u00a0 Besides, the hyperbolic example is merely a pedagogical technique.\u00c2\u00a0 The list, by the way, is by no means comprehensive; every day we are surprised to see the lengths to which people will go to win their arguments.\u00c2\u00a0 We might add a couple of our own “discoveries” at the end.<\/p>\n

But we ought to stress, by the way, that we would tend to consider these fallacies to be very simple and avoidable kinds of reasoning errors.\u00c2\u00a0 Avoiding them is as simple as drawing within the lines of a child’s coloring book–it takes a modicum of care, patience and honesty.\u00c2\u00a0 There are many more systematic errors than these, however.\u00c2\u00a0 Many of these consist in among other things psychological propensities to misjudge data, misread statistics, ignore our own biases and in general to make faulty predictions.\u00c2\u00a0 Some of these errors are exceedingly difficult to detect and avoid.\u00c2\u00a0 The same is not true, however, of the fallacies listed below.<\/p>\n

One final thing.\u00c2\u00a0 If this list doesn’t accord with your understanding of fallacies, feel free to leave a comment.<\/p>\n

I. Fallacies of relevance:<\/strong><\/p>\n

Certainly one of the most common types of fallacy in informal reasoning consists in drawing conclusions from reasons that are not “logically” relevant to the conclusion. The reasons, however, seem to be psychologically emotionally, rhetorically or, we might add, politically relevant to the conclusion being drawn. When someone’s conclusion doesn’t seem to have much to do with the premises, you might be in the presence of a fallacy of relevance. Here are some basic types.<\/p>\n

1. Ad hominem<\/em> (against the person): attacking the person making an argument rather than the argument or position the person is supporting. There are three basic varieties of ad hominem (as well as numerous sub-varieties–for those see Walton, 1998 in the Bibliography).<\/p>\n