Appendix 1

Appendix 1Logical FallaciesUnderstanding logical fallaciesPart 1What Are Logical Fallacies?A logical fallacy is an error in reasoning.When someone tries to argue based on erroneous reasoning, they are committing a logical fallacy.Some logical fallacies are more common than othersBeing able to pick out errors in your own reasoning and others is a great skill that is becoming increasingly rare.Formal vs. Informal FallaciesFormal fallacies are called deductive, while informal fallacies are called inductive.For each type of argument, there is a different understanding of what constitutes a fallacy.Formal arguments usually have a higher standard than informal ones.Formal (Deductive) Arguments and FallaciesFormal arguments must be water-tight.For a deductive argument to be valid, it must be impossible for both its premises to be true and its conclusion false.For example:1) All human beings are mortal.2) Socrates is a human beingTherefore:3) Socrates is mortal.Its simply not true that 1 and 2 are true and 3 is false, so this argument is deductively valid. Any deductive argument that fails to meet this high standard is fallacious it is a formal fallacy.Informal (Inductive) Arguments and FallaciesInductive arguments arent as rigorous as deductive arguments.Even if its premises are true, the argument still may have a false conclusion.All inductive arguments are technically invalid, and are therefore not right or wrong, but rather strong or weak.For example:1) The sun has come up every day in recorded history.Therefore:2) The sun will come up tomorrow.It is the informal fallacies that are of most concern to critical thinkers and guides to good thinking.Types of FallaciesWe can group informal fallacies as related to either relevance, ambiguity, or presumption.Arguments that commit fallacies of relevance rely on premises that are not relevant to the truth of the conclusion.Arguments that commit fallacies of ambiguity manipulate language in misleading ways.Arguments that commit fallacies of presumption contain false premises and fail to establish their conclusion.Lets look at some examples.Although there are many fallacies out there that we wont cover, these are the most common ones. Learn them so that you can avoid them in your own arguments, and also so that you can easily pick them out in others arguments.The FallaciesFallacies of RelevanceAd Hominem (Personal Attack)Arguments not focusing on evidence, but rather on the person making the claim, are guilty of the Ad Hominem fallacy.People committing this fallacy seek to discredit the people behind an idea rather than the idea itself.Its important to always attack arguments, not the arguers themselves.Ad Hominem: Example1) My pastor at church says that modern biology supports the idea of an intelligent designer.2) Hes compelled to say that because hes religious, and probably hasnt studied the issue.Therefore:3) Modern biology doesnt support an intelligent designer.BandwagonThe Bandwagon fallacy (also called the Appeal to Popularity) attempts to focus on the growing popularity of an idea as a basis for accepting its truth.This is a fallacy because there are many other areas of an idea that could increase its popularity other than truth, including peer pressure, tangible benefits, and even mass ignorance.Bandwagon: Example1) A recent study reveals that the idea of gender segregation in education is growing increasingly popular, and that as many as 80% of Americans think its a good idea.Therefore:2) Gender segregation in education is a good idea.

Appeal to Antiquity/TraditionThis fallacy assumes that older ideas are better, and the fact that because something has been around for a while implies that it is true or good.We cant, of course, learn anything about an idea simply based on how old it is.This fallacy in reverse the idea that something is good or true just because it is new is also a fallacy, called the Appeal to Novelty.Appeal to Antiquity/Tradition: Example1) The institution of slavery dates back to some of the worlds oldest civilizations, and even existed in early America.Therefore:2) Slavery must be good for civilizations.Appeal to AuthorityThis fallacy happens when the truth or validity of a claim is based (wholly or partly) on support from a supposed authority.Even a legitimate authority on a subject may affirm a falsehood, so no testimony is ever guaranteed to be true.However, this informal fallacy only occurs when the speaker on the topic is either not an authority at all, or is not an authority on the subject at hand.Appeal to Authority: Example1) My math teacher said that George Washington never cut down a cherry tree.Therefore:2) George Washington never cut down a cherry tree.

*Note that the conclusion here may be true, but as the math teacher is an authority in math and not history, appealing to him or her would be a fallacy.Appeal to PityAn Appeal to Pity happens when an arguer attempts to persuade using sympathy rather than evidence.Our emotional responses are not always a good guide to truth.Emotions tend to cloud, rather than clarify, issues.In seeking truth, we should base our beliefs on reason rather than emotion.Appeal to Pity: ExampleA common example of the Appeal to Pity is in the pro-life practice of picketing with posters that display images of aborted fetuses. By showing people pictures of dead babies, they hope to create anger and disgust in people so they will turn against the practice of abortion.Red HerringThis logical fallacy is a common debate tactic that you should always watch out for.A Red Herring happens when someone attempts to divert attention from an argument by introducing a new topic.The diversion often seems to be related to the argument, and therefore its easy to get an opponent off track.A Red Herring can be both frustrating and effective but always remember that it is also fallacious.Red Herring: Example1) I missed the deadline for my exam.2) I was up all night with my sick daughter, and was then in a car accident this morning, and so I was tired and overwhelmed and completely lost track of time.Therefore:3) I should be allowed to make up the exam.*Notice that this Red Herring also takes the form of an Appeal to Pity.False AnalogyA False (or Weak) Analogy attempts to rely on an analogy in order to persuade.However, the strength of an analogy rests on the strength of the comparison being made.The fallacy happens with the analogys comparison is not strong enough.False Analogy: Example (designed by William Paley)1) A watch and the universe are similar in that they both display order and complexity.2) A watch is the product of intelligent design.Therefore:3) The universe must be the product of intelligent design.

The question here is whether or not the similarities in the kind and degree of order exhibited by watches and the universe are sufficient enough to support an inference in the similarity of their origins.Fallacies of AmbiguityStraw ManThis fallacy happens when someone presents an argument as weaker than it actually is.When an argument is misrepresented as weaker than it is, it can be easily knocked down (like a straw man).When this happens, though, what has actually been refuted is not the real issue, and therefore presents a fallacy.Straw Man: Example1) The Christian belief in a Trinity proposes that three equals one.2) Three does not equal one.Therefore:3) The belief in a Trinity is false.

Fallacies of PresumptionAppeal to IgnoranceArguments from ignorance propose a claim to be true because it hasnt been proven to be false.Sometimes arguers claim that their positions are justified because they havent been proven false, but remember that this is fallacious.Appeal to Ignorance: Example1) No one has been able to disprove the existence of mermaids and sirens.Therefore:2) I am justified in believing that mermaids and sirens exist.

*The argument is fallacious because the non-existence of mermaids is perfectly consistent with no one having been able to prove their non-existence.Begging the Question (Circular Reasoning)An argument is circular if its conclusion is among its premises or if it assumes what it is trying to prove.These arguments are said to beg the question.Circular arguments fail as proof because it will only be judged to be sound by those who already accept the conclusion.Begging the Question: Example1) Women have a right to choose an abortion or notTherefore:2) Abortion should be legal.

*Having a right to X is the same as other people having an obligation to allow you to have X, so this argument begs the question, assuming exactly what it is trying to prove. The same would be said of 1) the unborn have a right to life, and therefore 2) abortion should be illegal.False DilemmaThe false dilemma happens when people are asked to choose between only two options when there is at least one other option available.This fallacy is an attempt to make people think that a certain issue is black and white, when in fact it is gray, and urge them into a decision.False Dilemma: ExampleThere are a few examples we can look to in terms of this fallacy.One example is the famous Pascals Wager. It presents that a person is better off choosing to be a Christian because 1) they lose nothing if theyre wrong and 2) they gain everything if theyre right; while 1) nonbelievers lose everything if theyre wrong and 2) gain nothing if theyre right. This is a false dilemma because its not taking into account the many other heavens and hells besides the Christian one(s) that might damn the Christian, or the monetary and time losses a Christian might experience if wrong.Another example is any time a person says, Youre either with us or against us. This reasoning is leaving out the possibility of neutrality which, especially in times of war, is often a very viable position that claims to neither be for or against either side.Hasty GeneralizationA Hasty Generalization happens when an arguer draws a conclusion from a small, and perhaps atypical, case.The conclusions drawn may very well be false, as the example used is often not typical.Hasty Generalization: Example1) My lawyer neighbor is very grouchy.Therefore:2) All lawyers must be grouchy.Post HocThe term literally means, after this, therefore because of this.This fallacy occurs when an arguer assumes that because one thing occurred after another, it occurred because of it.Mere temporal succession, however, does not entail causal succession.Post Hoc: Example1) School shootings began happening soon after we removed prayer from schools.Therefore:2) Removing prayer from schools resulted in school shootings.Slippery SlopeThis fallacy assumes that one thing must lead to another.The slippery slope fallacy happens when we say that one thing leads to another, which will lead to something else, and before we know it well be led to something we definitely dont want.The fallacy happens when its recognized that its possible to complete the first step without falling down the slope of the supposed subsequent steps.Slippery Slope: Example1) We cant legalize marijuana because then wed be legalizing heroin, LSD, cocaine, and all other illegal drugs.Therefore:2) Legalization of marijuana will lead to legalization of every illegal drug imaginable.