I Learnt a Small Program but When I Tried to Write the Same One Again I Am Missing the Logic

What this handout is virtually

This handout discusses common logical fallacies that you may run into in your own writing or the writing of others. The handout provides definitions, examples, and tips on fugitive these fallacies.

Arguments

Most academic writing tasks crave you to brand an argument—that is, to present reasons for a particular claim or interpretation you are putting frontwards. You may have been told that you need to make your arguments more logical or stronger. And you may accept worried that y'all merely aren't a logical person or wondered what it means for an argument to exist stiff. Learning to make the best arguments you tin can is an ongoing process, but information technology isn't incommunicable: "Being logical" is something anyone tin do, with exercise.

Each argument you make is composed of premises (this is a term for statements that express your reasons or bear witness) that are arranged in the right way to support your conclusion (the main merits or interpretation you lot are offering). You tin can make your arguments stronger by:

using good premises (ones you take good reason to believe are both true and relevant to the upshot at hand),
making sure your bounds provide skilful back up for your conclusion (and not some other conclusion, or no conclusion at all),
checking that y'all have addressed the virtually of import or relevant aspects of the event (that is, that your premises and conclusion focus on what is actually important to the consequence), and
not making claims that are so stiff or sweeping that you can't actually support them.

You lot also need to be certain that you present all of your ideas in an orderly style that readers can follow. See our handouts on argument and organisation for some tips that will improve your arguments.

This handout describes some ways in which arguments ofttimes neglect to exercise the things listed above; these failings are called fallacies. If you're having trouble developing your argument, check to see if a fallacy is part of the problem.

Information technology is especially like shooting fish in a barrel to skid up and commit a fallacy when you take potent feelings about your topic—if a determination seems obvious to you, you're more likely to just assume that information technology is true and to be devil-may-care with your show. To aid y'all encounter how people commonly brand this mistake, this handout uses a number of controversial political examples—arguments about subjects like abortion, gun control, the decease penalty, gay wedlock, euthanasia, and pornography. The purpose of this handout, though, is not to argue for whatsoever detail position on any of these issues; rather, it is to illustrate weak reasoning, which can happen in pretty much any kind of argument. Please be aware that the claims in these examples are just made-upwardly illustrations—they oasis't been researched, and y'all shouldn't use them as evidence in your own writing.

What are fallacies?

Fallacies are defects that weaken arguments. Past learning to await for them in your own and others' writing, you lot tin can strengthen your ability to evaluate the arguments you make, read, and hear. Information technology is important to realize two things nigh fallacies: first, fallacious arguments are very, very mutual and tin be quite persuasive, at least to the casual reader or listener. You lot can observe dozens of examples of fallacious reasoning in newspapers, advertisements, and other sources. 2nd, it is sometimes difficult to evaluate whether an argument is beguiling. An argument might exist very weak, somewhat weak, somewhat strong, or very stiff. An argument that has several stages or parts might accept some strong sections and some weak ones. The goal of this handout, then, is not to teach you how to label arguments every bit fallacious or fallacy-free, but to aid you look critically at your own arguments and movement them away from the "weak" and toward the "strong" terminate of the continuum.

So what practise fallacies look like?

For each fallacy listed, at that place is a definition or explanation, an example, and a tip on how to avoid committing the fallacy in your own arguments.

Hasty generalization

Definition: Making assumptions about a whole group or range of cases based on a sample that is inadequate (usually considering it is atypical or likewise small). Stereotypes about people ("librarians are shy and smart," "wealthy people are snobs," etc.) are a common instance of the principle underlying jerky generalization.

Example: "My roommate said her philosophy form was hard, and the one I'm in is hard, also. All philosophy classes must be hard!" Two people'south experiences are, in this case, not enough on which to base a decision.

Tip: Ask yourself what kind of "sample" you're using: Are y'all relying on the opinions or experiences of merely a few people, or your ain experience in just a few situations? If so, consider whether y'all need more show, or perhaps a less sweeping determination. (Notice that in the instance, the more than modest conclusion "Some philosophy classes are hard for some students" would not be a hasty generalization.)

Missing the point

Definition: The bounds of an argument exercise back up a item decision—only not the conclusion that the arguer actually draws.

Example: "The seriousness of a punishment should match the seriousness of the crime. Right now, the penalization for drunk driving may simply be a fine. But drunk driving is a very serious criminal offense that tin kill innocent people. So the capital punishment should exist the punishment for drunk driving." The argument actually supports several conclusions—"The punishment for drunkard driving should be very serious," in item—simply information technology doesn't support the merits that the death penalty, specifically, is warranted.

Tip: Separate your bounds from your conclusion. Looking at the premises, ask yourself what conclusion an objective person would attain after reading them. Looking at your conclusion, ask yourself what kind of evidence would exist required to support such a determination, and and then see if you've really given that evidence. Missing the point often occurs when a sweeping or extreme determination is being drawn, so be especially careful if you know you're claiming something big.

Post hoc (also chosen simulated cause)

This fallacy gets its name from the Latin phrase "post hoc, ergo propter hoc," which translates equally "after this, therefore because of this."

Definition: Assuming that because B comes after A, A caused B. Of grade, sometimes one event really does cause another one that comes later—for example, if I register for a class, and my proper name afterwards appears on the gyre, it's true that the first effect acquired the ane that came subsequently. But sometimes two events that seem related in time aren't really related every bit crusade and event. That is, correlation isn't the aforementioned affair as causation.

Examples: "President Jones raised taxes, and then the charge per unit of tearing law-breaking went up. Jones is responsible for the rise in crime." The increment in taxes might or might non be one gene in the ascension crime rates, but the argument hasn't shown us that i caused the other.

Tip: To avert the mail hoc fallacy, the arguer would need to give us some caption of the process by which the tax increase is supposed to accept produced higher crime rates. And that's what you should do to avoid committing this fallacy: If yous say that A causes B, you should have something more than to say about how A caused B than just that A came first and B came later.

Slippery slope

Definition: The arguer claims that a sort of chain reaction, ordinarily ending in some dire consequence, will take place, but there's really not enough evidence for that assumption. The arguer asserts that if we accept fifty-fifty one stride onto the "slippery slope," we will end upwards sliding all the way to the bottom; he or she assumes nosotros can't stop partway down the hill.

Example: "Animal experimentation reduces our respect for life. If we don't respect life, we are probable to exist more and more tolerant of violent acts like war and murder. Shortly our society will become a battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent this terrible consequence, nosotros should make animal experimentation illegal correct now." Since creature experimentation has been legal for some time and civilization has not nonetheless ended, it seems particularly clear that this chain of events won't necessarily accept identify. Even if we believe that experimenting on animals reduces respect for life, and loss of respect for life makes us more tolerant of violence, that may exist the spot on the hillside at which things end—we may not slide all the mode downwards to the terminate of civilization. And so we take non yet been given sufficient reason to accept the arguer'due south conclusion that we must make animal experimentation illegal correct at present.

Like post hoc, slippery gradient tin can be a tricky fallacy to place, since sometimes a chain of events actually can be predicted to follow from a certain activeness. Hither's an case that doesn't seem fallacious: "If I fail English 101, I won't be able to graduate. If I don't graduate, I probably won't be able to get a practiced task, and I may very well end up doing temp work or flipping burgers for the next yr."

Tip: Check your argument for chains of consequences, where you say "if A, then B, and if B, then C," and so forth. Make certain these chains are reasonable.

Weak analogy

Definition: Many arguments rely on an analogy between two or more objects, ideas, or situations. If the two things that are existence compared aren't really alike in the relevant respects, the illustration is a weak i, and the argument that relies on it commits the fallacy of weak analogy.

Instance: "Guns are like hammers—they're both tools with metallic parts that could exist used to kill someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on purchasing guns are equally ridiculous." While guns and hammers do share certain features, these features (having metal parts, being tools, and being potentially useful for violence) are not the ones at stake in deciding whether to restrict guns. Rather, nosotros restrict guns considering they can easily be used to impale big numbers of people at a distance. This is a feature hammers do not share—it would be hard to impale a oversupply with a hammer. Thus, the illustration is weak, and so is the statement based on it.

If you remember about it, you lot can make an analogy of some kind between almost any 2 things in the world: "My newspaper is like a mud puddle because they both get bigger when it rains (I work more when I'm stuck inside) and they're both kind of murky." So the mere fact that you tin depict an analogy between ii things doesn't prove much, by itself.

Arguments by illustration are often used in discussing ballgame—arguers frequently compare fetuses with adult human beings, and then argue that treatment that would violate the rights of an adult man existence also violates the rights of fetuses. Whether these arguments are good or not depends on the strength of the illustration: do adult humans and fetuses share the properties that give adult humans rights? If the property that matters is having a human genetic code or the potential for a life full of homo experiences, adult humans and fetuses practice share that property, and so the statement and the analogy are strong; if the holding is being cocky-enlightened, rational, or able to survive on one's ain, adult humans and fetuses don't share it, and the analogy is weak.

Tip: Identify what properties are important to the claim you're making, and run into whether the two things you're comparing both share those properties.

Appeal to authority

Definition: Often we add forcefulness to our arguments past referring to respected sources or regime and explaining their positions on the issues we're discussing. If, however, we endeavor to get readers to agree with us but by impressing them with a famous proper name or past appealing to a supposed dominance who really isn't much of an expert, we commit the fallacy of appeal to authorization.

Example: "We should cancel the decease penalty. Many respected people, such as player Guy Handsome, take publicly stated their opposition to information technology." While Guy Handsome may be an authority on matters having to do with acting, at that place's no detail reason why anyone should be moved by his political opinions—he is probably no more than of an authority on the death penalty than the person writing the newspaper.

Tip: There are two easy ways to avert committing entreatment to authority: Outset, make sure that the authorities you cite are experts on the subject you're discussing. Second, rather than merely saying "Dr. Authority believes X, then we should believe information technology, as well," attempt to explain the reasoning or evidence that the potency used to go far at his or her opinion. That way, your readers have more to keep than a person's reputation. It also helps to choose authorities who are perceived as adequately neutral or reasonable, rather than people who will be perceived as biased.

Advertisement populum

Definition: The Latin name of this fallacy means "to the people." At that place are several versions of the advertising populum fallacy, but in all of them, the arguer takes advantage of the desire most people have to be liked and to fit in with others and uses that desire to try to get the audience to accept his or her statement. One of the most mutual versions is the bandwagon fallacy, in which the arguer tries to convince the audience to exercise or believe something considering anybody else (supposedly) does.

Example: "Gay marriages are just immoral. 70% of Americans think so!" While the stance of virtually Americans might exist relevant in determining what laws we should have, it certainly doesn't make up one's mind what is moral or immoral: at that place was a time where a substantial number of Americans were in favor of segregation, just their stance was not evidence that segregation was moral. The arguer is trying to get united states of america to agree with the decision past appealing to our desire to fit in with other Americans.

Tip: Make sure that you aren't recommending that your readers believe your conclusion considering everyone else believes it, all the cool people believe it, people will similar you better if you believe it, so forth. Keep in listen that the popular opinion is not always the correct 1.

Advertising hominem and tu quoque

Definitions: Like the appeal to authority and advertising populum fallacies, the ad hominem ("confronting the person") and tu quoque ("you, too!") fallacies focus our attention on people rather than on arguments or evidence. In both of these arguments, the conclusion is unremarkably "You shouldn't believe And so-and-Then's argument." The reason for not assertive So-and-So is that And so-and-And so is either a bad person (ad hominem) or a hypocrite (tu quoque). In an ad hominem argument, the arguer attacks his or her opponent instead of the opponent's argument.

Examples: "Andrea Dworkin has written several books arguing that pornography harms women. But Dworkin is just ugly and bitter, then why should we listen to her?" Dworkin's appearance and character, which the arguer has characterized then ungenerously, have goose egg to do with the strength of her statement, so using them as bear witness is fallacious.

In a tu quoque argument, the arguer points out that the opponent has actually done the thing he or she is arguing confronting, and and so the opponent's argument shouldn't be listened to. Hither's an example: imagine that your parents have explained to yous why you lot shouldn't smoke, and they've given a lot of proficient reasons—the damage to your health, the price, and then forth. Y'all reply, "I won't accept your argument, considering you used to fume when yous were my age. You did it, besides!" The fact that your parents take done the affair they are condemning has no begetting on the premises they put forward in their argument (smoking harms your health and is very expensive), so your response is fallacious.

Tip: Be sure to stay focused on your opponents' reasoning, rather than on their personal character. (The exception to this is, of form, if y'all are making an argument about someone'due south character—if your conclusion is "President Jones is an untrustworthy person," premises about her untrustworthy acts are relevant, not fallacious.)

Appeal to compassion

Definition: The appeal to pity takes place when an arguer tries to go people to take a conclusion by making them feel sorry for someone.

Examples: "I know the exam is graded based on performance, but you should give me an A. My cat has been ill, my car broke downwardly, and I've had a cold, and then it was really hard for me to study!" The conclusion hither is "Y'all should give me an A." But the criteria for getting an A have to do with learning and applying the material from the course; the principle the arguer wants united states to have (people who have a hard calendar week deserve A's) is clearly unacceptable. The information the arguer has given might feel relevant and might even get the audience to consider the conclusion—merely the information isn't logically relevant, and so the argument is fallacious. Here'due south another example: "It's wrong to tax corporations—think of all the coin they give to charity, and of the costs they already pay to run their businesses!"

Tip: Make sure that y'all aren't simply trying to go your audience to agree with you by making them feel sorry for someone.

Appeal to ignorance

Definition: In the entreatment to ignorance, the arguer basically says, "Look, there's no conclusive evidence on the event at hand. Therefore, you should accept my determination on this upshot."

Example: "People accept been trying for centuries to prove that God exists. Simply no i has yet been able to prove it. Therefore, God does not exist." Hither's an opposing argument that commits the same fallacy: "People have been trying for years to evidence that God does not be. But no i has yet been able to show it. Therefore, God exists." In each case, the arguer tries to employ the lack of evidence every bit back up for a positive claim well-nigh the truth of a conclusion. There is one situation in which doing this is not fallacious: if qualified researchers have used well-idea-out methods to search for something for a long time, they haven't found it, and it'south the kind of thing people ought to be able to find, then the fact that they oasis't establish information technology constitutes some show that it doesn't exist.

Tip: Look closely at arguments where you signal out a lack of prove and then draw a conclusion from that lack of testify.

Straw human

Definition: One way of making our ain arguments stronger is to anticipate and respond in advance to the arguments that an opponent might make. In the harbinger man fallacy, the arguer sets upwards a weak version of the opponent's position and tries to score points by knocking it downward. But just equally being able to knock downwardly a straw man (like a scarecrow) isn't very impressive, defeating a watered-down version of your opponent'due south statement isn't very impressive either.

Instance: "Feminists want to ban all pornography and punish everyone who looks at information technology! But such harsh measures are surely inappropriate, so the feminists are wrong: porn and its fans should be left in peace." The feminist argument is made weak past beingness overstated. In fact, most feminists practise not propose an outright "ban" on porn or any punishment for those who merely view it or approve of it; often, they advise some restrictions on detail things similar child porn, or propose to let people who are injure past porn to sue publishers and producers—non viewers—for damages. So the arguer hasn't really scored whatever points; he or she has only committed a fallacy.

Tip: Be charitable to your opponents. Country their arguments every bit strongly, accurately, and sympathetically as possible. If you can knock down even the best version of an opponent'south argument, then you've really achieved something.

Red herring

Definition: Partway through an argument, the arguer goes off on a tangent, raising a side issue that distracts the audience from what's actually at stake. Oft, the arguer never returns to the original issue.

Example: "Grading this test on a curve would be the nigh fair affair to practise. Later all, classes get more smoothly when the students and the professor are getting forth well." Allow's endeavour our premise-conclusion outlining to see what's wrong with this argument:

Premise: Classes become more smoothly when the students and the professor are getting forth well.

Decision: Grading this exam on a curve would be the near fair thing to practise.

When we lay it out this way, it's pretty obvious that the arguer went off on a tangent—the fact that something helps people get along doesn't necessarily make it more off-white; fairness and justice sometimes crave us to do things that cause conflict. Merely the audition may feel like the effect of teachers and students like-minded is important and be distracted from the fact that the arguer has not given any evidence as to why a curve would be fair.

Tip: Attempt laying your premises and decision out in an outline-like form. How many bug practise yous see being raised in your argument? Can y'all explicate how each premise supports the determination?

False dichotomy

Definition: In false dichotomy, the arguer sets upward the situation so it looks like there are only two choices. The arguer then eliminates one of the choices, so it seems that we are left with simply i selection: the i the arguer wanted us to pick in the first place. But oft there are actually many different options, not simply ii—and if we idea about them all, we might not be and so quick to selection the one the arguer recommends.

Example: "Caldwell Hall is in bad shape. Either we tear it downwards and put up a new edifice, or nosotros go on to take a chance students' safety. Obviously we shouldn't gamble anyone'southward prophylactic, so we must tear the edifice down." The argument neglects to mention the possibility that we might repair the edifice or detect some mode to protect students from the risks in question—for example, if simply a few rooms are in bad shape, maybe we shouldn't hold classes in those rooms.

Tip: Examine your own arguments: if you're proverb that we have to choose between simply two options, is that really so? Or are at that place other alternatives you lot oasis't mentioned? If at that place are other alternatives, don't merely ignore them—explain why they, besides, should be ruled out. Although there'due south no formal name for it, assuming that there are merely three options, iv options, etc. when really there are more than is like to false dichotomy and should also be avoided.

Begging the question

Definition: A complicated fallacy; information technology comes in several forms and can be harder to notice than many of the other fallacies we've discussed. Basically, an argument that begs the question asks the reader to simply accept the conclusion without providing real testify; the argument either relies on a premise that says the aforementioned thing every bit the conclusion (which y'all might hear referred to as "beingness round" or "circular reasoning"), or simply ignores an important (but questionable) supposition that the argument rests on. Sometimes people use the phrase "beg the question" as a sort of full general criticism of arguments, to mean that an arguer hasn't given very good reasons for a conclusion, but that'due south not the meaning we're going to discuss here.

Examples: "Active euthanasia is morally acceptable. Information technology is a decent, ethical thing to assistance some other human escape suffering through expiry." Allow's lay this out in premise-conclusion grade:

Premise: It is a decent, ethical matter to aid another human being escape suffering through death.

Conclusion: Active euthanasia is morally adequate.

If we "translate" the premise, we'll see that the arguer has really only said the same thing twice: "decent, upstanding" ways pretty much the same thing as "morally acceptable," and "assist another human escape suffering through expiry" ways something pretty similar to "active euthanasia." And then the premise basically says, "active euthanasia is morally adequate," just like the conclusion does. The arguer hasn't yet given the states whatever real reasons why euthanasia is acceptable; instead, she has left us request "well, actually, why exercise you think active euthanasia is adequate?" Her statement "begs" (that is, evades) the real question.

Here's a second example of begging the question, in which a dubious premise which is needed to make the argument valid is completely ignored: "Murder is morally incorrect. So active euthanasia is morally wrong." The premise that gets left out is "active euthanasia is murder." And that is a debatable premise—again, the argument "begs" or evades the question of whether active euthanasia is murder by simply not stating the premise. The arguer is hoping nosotros'll just focus on the uncontroversial premise, "Murder is morally wrong," and non notice what is being assumed.

Tip: One mode to endeavour to avoid begging the question is to write out your premises and conclusion in a brusque, outline-like class. See if you lot find any gaps, any steps that are required to motility from i premise to the next or from the bounds to the conclusion. Write downward the statements that would fill up those gaps. If the statements are controversial and you've just glossed over them, you might be begging the question. Side by side, bank check to run across whether whatever of your premises basically says the aforementioned thing equally the conclusion (only in different words). If and so, you're probably begging the question. The moral of the story: y'all tin't only assume or use equally uncontroversial prove the very thing you lot're trying to prove.

Equivocation

Definition: Equivocation is sliding between 2 or more than different meanings of a single word or phrase that is important to the argument.

Example: "Giving money to charity is the right affair to do. So charities accept a correct to our coin." The equivocation here is on the word "right": "right" tin can mean both something that is right or good (as in "I got the correct answers on the examination") and something to which someone has a claim (every bit in "everyone has a correct to life"). Sometimes an arguer will deliberately, sneakily equivocate, ofttimes on words like "freedom," "justice," "rights," and so forth; other times, the equivocation is a mistake or misunderstanding. Either way, it's important that you use the master terms of your argument consistently.

Tip: Identify the about important words and phrases in your argument and ask yourself whether they could have more than than one significant. If they could, be sure y'all aren't slipping and sliding between those meanings.

So how do I find fallacies in my own writing?

Hither are some general tips for finding fallacies in your own arguments:

Pretend you lot disagree with the decision you lot're defending. What parts of the statement would now seem fishy to yous? What parts would seem easiest to attack? Give special attention to strengthening those parts.
List your chief points; under each i, list the prove you have for information technology. Seeing your claims and show laid out this way may make y'all realize that you have no skilful evidence for a particular claim, or it may assistance you await more than critically at the evidence yous're using.
Learn which types of fallacies yous're peculiarly prone to, and be careful to cheque for them in your work. Some writers make lots of appeals to authority; others are more probable to rely on weak analogies or ready straw men. Read over some of your quondam papers to come across if there's a particular kind of fallacy yous need to picket out for.
Be aware that broad claims need more proof than narrow ones. Claims that use sweeping words like "all," "no," "none," "every," "e'er," "never," "no one," and "everyone" are sometimes appropriate—simply they require a lot more than proof than less-sweeping claims that use words like "some," "many," "few," "sometimes," "commonly," and and so forth.
Double cheque your characterizations of others, peculiarly your opponents, to exist certain they are accurate and fair.

Can I get some do with this?

Yes, you can. Follow this link to see a sample argument that's total of fallacies (and and then you can follow some other link to go an caption of each one). Then there's a more than well-constructed argument on the same topic.

Works consulted

We consulted these works while writing this handout. This is non a comprehensive list of resources on the handout'south topic, and we encourage you lot to do your own research to find boosted publications. Please do not use this listing as a model for the format of your own reference list, as it may not match the commendation style you are using. For guidance on formatting citations, please encounter the UNC Libraries commendation tutorial. We revise these tips periodically and welcome feedback.

Copi, Irving M., Carl Cohen, and Victor Rodych. 1998. Introduction to Logic. London: Pearson Educational activity.

Hurley, Patrick J. 2000. A Concise Introduction to Logic, 7th ed. Belmont, CA: Wadsworth.

Lunsford, Andrea A., and John J. Ruszkiewicz. 2016. Everything's an Argument, 7th ed. Boston: Bedford/St Martin'due south.

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