Logic.docx

FALLACY Introduction Fallacies is an important part of logic and one that can immediately enrich once life. It will helps develop the vocabulary and skills needed to better evaluate the arguments of politicians, neighbors, advertisers, authorities, and people. Much of philosophy is about identifying and evaluating arguments and studying fallacies can help people do both better. Fallacies is also a mark of a well-educated mind and it greatly enriches the quality of philosophical discussions. In short, students who studied both formal and informal fallacies can more easily engage in philosophy at the highest levels. In a similar way, some people think of fallacies as “a bunch of bad arguments." They cannot distinguish among the fallacies and are lost, though they may not know it. While it is true that all fallacies are faulty inferences, each fallacy is different and knowing the name and pattern of each can clarify the way of thinking, improve debating skills, and help people better discover truth. Fallacies have a form that is always and absolutely fallacious/invalid whereas informal fallacies have a form that is sometimes non fallacious. Learning the formal fallacies is far more beneficial than most people realize. Studying fallacies will help people better evaluate all kinds of arguments. Committing fallacies is not always a bad thing. Recognizing fallacious tendencies and cognitive biases can make a person more human. Definition  Fallacies are simply invalid or faulty arguments.  Fallacy is not a precise term. It is ambiguous. It can refer either to: 1. Kind of error in an argument 2. Kind of error in reasoning (including arguments, definitions, explanations, and others) 3. False belief, or 4. The cause of any of the previous errors including what are normally referred to as rhetorical techniques. KINDS OF FALLACY 1. Hasty Generalization  Making assumptions about a whole group or range of cases based on a sample that is inadequate. Stereotypes about people are a common example of the principle underlying hasty generalization.  An inference drawn from insufficient evidence. Examples:

I. My roommate said her philosophy class was hard, and the one I’m in is hard, too. All philosophy classes must be hard! Two people’s experiences are, in this case, not enough on which to base a conclusion. II. It is warmer this year in Las Vegas as compared to last year; therefore, global warming is rapidly accelerating. 2. Missing the Point  The premises of an argument do support a particular conclusion—but not the conclusion that the arguer actually draws. Example: The seriousness of a punishment should match the seriousness of the crime. Right now, the punishment for drunk driving may simply be a fine. But drunk driving is a very serious crime that can kill innocent people. So the death penalty should be the punishment for drunk driving.

The argument actually supports several conclusions. The punishment for drunk driving should be very serious, in particular but it doesn’t support the claim that the death penalty, specifically, is warranted. 3. Post Hoc (False Cause)  This fallacy gets its name from the Latin phrase “post hoc, ergo propter hoc,” which translates as “after this, therefore because of this.”  Assuming that because B comes after A, A caused B. Of course, sometimes one event really does cause another one that comes later. Examples: I.

If I register for a class, and my name later appears on the roll, it’s true that the first event caused the one that came later.

But sometimes two events that seem related in time aren’t really related as cause and event. That is, correlation isn’t the same thing as causation. II.

President Jones raised taxes, and then the rate of violent crime went up. Jones is responsible for the rise in crime.”

The increase in taxes might or might not be one factor in the rising crime rates, but the argument hasn’t shown us that one caused the other.

4. Slippery Slope  This error happens when one contends that an exceptionally minor movement will unavoidably prompt great and frequently ludicrous conclusions.

 The arguer claims that a sort of chain reaction, usually ending in some dire consequence, will take place, but there’s really not enough evidence for that assumption. Examples: I.

Animal experimentation reduces our respect for life. If we don’t respect life, we are likely to be more and more tolerant of violent acts like war and murder. Soon 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, we should make animal experimentation illegal right now. Since animal experimentation has been legal for some time and civilization has not yet ended, it seems particularly clear that this chain of events won’t necessarily take place. 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 be the spot on the hillside at which things stop we may not slide all the way down to the end of civilization. And so we have not yet been given sufficient reason to accept the arguer’s conclusion that we must make animal experimentation illegal right now.

II.

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 good job, and I may very well end up doing temp work or flipping burgers for the next year.

5. Weak Analogy  Many arguments rely on an analogy between two or more objects, ideas, or situations. If the two things that are being compared aren’t really alike in the relevant respects, the analogy is a weak one, and the argument that relies on it commits the fallacy of weak analogy. Examples: I.

Guns are like hammers they’re both tools with metal parts that could be 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 are not the ones at stake in deciding whether to restrict guns. Rather, we restrict guns because they can easily be used to kill large numbers of people at a distance. This is a feature hammers do not share it would be hard to kill a crowd with a hammer. Thus, the analogy is weak, and so is the argument based on it.

II.

My paper is like a mud puddle because they both get bigger when it rains and they’re both kind of murky. So the mere fact that you can draw an analogy between two things doesn’t prove much, by itself.

Arguments by analogy are often used in discussing abortion arguers frequently compare fetuses with adult human beings, and then argue that treatment that would violate the rights of an adult human being also violates the rights of fetuses. Whether these arguments are good or not depends on the strength of the analogy: 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 human experiences, adult humans and fetuses do share that property, so the argument and the analogy are strong; if the property is being self-aware, rational, or able to survive on one’s own, adult humans and fetuses don’t share it, and the analogy is weak. 6. Appeal to Authority  This sort of error is also known as “Argumentum Verecundia” (argument from modesty). Instead of concentrating on the benefits of an argument, the arguer will attempt to append their argument to an individual of power or authority, in an effort to give trustworthiness to their argument.  Often we add strength to our arguments by referring to respected sources or authorities and explaining their positions on the issues we’re discussing. If, however, we try to get readers to agree with us simply by impressing them with a famous name or by appealing to a supposed authority who really isn’t much of an expert, we commit the fallacy of appeal to authority. Example: We should abolish the death penalty. Many respected people, such as actor Guy Handsome, have publicly stated their opposition to it. While Guy Handsome may be an authority on matters having to do with acting, there’s no particular reason why anyone should be moved by his political opinions he is probably no more of an authority on the death penalty than the person writing the paper. 7. Ad Populum  The Latin name of this fallacy means “to the people.” There are several versions of the ad 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 argument. One of the most common versions is the bandwagon fallacy, in which the arguer tries to convince the audience to do or believe something because everyone else (supposedly) does. Example: Gay marriages are just immoral. 70% of Americans think so! While the opinion of most Americans might be relevant in determining what laws we should have, it certainly doesn’t determine what is moral or immoral: there was a time where a substantial number of Americans were in favor of segregation, but their opinion was not evidence that segregation was moral.

The arguer is trying to get us to agree with the conclusion by appealing to our desire to fit in with other Americans. 8. Ad Hominem and Tu Quoque  Like the appeal to authority and ad populum fallacies, the ad hominem (against 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 usually “You shouldn’t believe So-and-So’s argument.” The reason for not believing So-and-So is that So-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, so why should we listen to her?” Dworkin’s appearance and character, which the arguer has characterized so ungenerously, have nothing to do with the strength of her argument, so using them as evidence is fallacious.  In a tu quoque argument, the arguer points out that the opponent has actually done the thing he or she is arguing against, and so the opponent’s argument shouldn’t be listened to. Example: Imagine that your parents have explained to you why you shouldn’t smoke, and they’ve given a lot of good reasons like the damage to your health, the cost, and so forth. You reply, “I won’t accept your argument, because you used to smoke when you were my age. You did it, too!” The fact that your parents have done the thing they are condemning has no bearing on the premises they put forward in their argument, so your response is fallacious. 9. Appeal to Pity  The appeal to pity takes place when an arguer tries to get people to accept a conclusion by making them feel sorry for someone. Examples: I.

I know the exam is graded based on performance, but you should give me an A. My cat has been sick, my car broke down, and I’ve had a cold, so it was really hard for me to study! The conclusion here is “You 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 us to accept is clearly unacceptable. The information the arguer has given might feel relevant and might even get the audience to consider the conclusion but the information isn’t logically relevant, and so the argument is fallacious.

II.

It’s wrong to Tax Corporation’s think of all the money they give to charity, and of the costs they already pay to run their businesses!

10. Appeal to Ignorance  Appeal to ignorance happens when one individual utilizes another individual’s lack of information on a specific subject as proof that his or her own particular argument is right.  In the appeal to ignorance, the arguer basically says, look, there’s no conclusive evidence on the issue at hand. Therefore, you should accept my conclusion on this issue. Example: People have been trying for centuries to prove that God exists. But no one has yet been able to prove it. Therefore, God does not exist. People have been trying for years to prove that God does not exist. But no one has yet been able to prove it. Therefore, God exists. In each case, the arguer tries to use the lack of evidence as support for a positive claim about the truth of a conclusion. There is one situation in which doing this is not fallacious: if qualified researchers have used well-thought-out methods to search for something for a long time, they haven’t found it, and it’s the kind of thing people ought to be able to find, then the fact that they haven’t found it constitutes some evidence that it doesn’t exist. 11. Straw Man  In the straw man fallacy, the arguer sets up a weak version of the opponent’s position and tries to score points by knocking it down. But just as being able to knock down a straw man isn’t very impressive, defeating a watered-down version of your opponent’s argument isn’t very impressive either. Example: Feminists want to ban all pornography and punish everyone who looks at it! 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 by being overstated. In fact, most feminists do not propose an outright “ban” on porn or any punishment for those who merely view it or approve of it; often, they propose some restrictions on particular things like child porn, or propose to allow people who are hurt by porn to sue publishers and producers not viewers for damages. So the arguer hasn’t really scored any points; he or she has just committed a fallacy.

12. Red Herring  Partway through an argument, the arguer goes off on a tangent, raising a side issue that distracts the audience from what’s really at stake. Often, the arguer never returns to the original issue. Example: Grading this exam on a curve would be the fairest thing to do. After all, classes go more smoothly when the students and the professor are getting along well. Premise: Classes go more smoothly when the students and the professor are getting along well. Conclusion: Grading this exam on a curve would be the fairest thing to do. 13. False Dichotomy  In false dichotomy, the arguer sets up 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 only one option: the one the arguer wanted us to pick in the first place. But often there are really many different options, not just two and if we thought about them all, we might not be so quick to pick the one the arguer recommends. Example: Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we continue to risk students’ safety. Obviously we shouldn’t risk anyone’s safety, so we must tear the building down. The argument neglects to mention the possibility that we might repair the building or find some way to protect students from the risks in question for example, if only a few rooms are in bad shape, perhaps we shouldn’t hold classes in those rooms. 14. Begging the Question  A complicated fallacy; it comes in several forms and can be harder to detect than many of the other fallacies. Basically, an argument that begs the question asks the reader to simply accept the conclusion without providing real evidence; the argument either relies on a premise that says the same thing as the conclusion, or simply ignores an important assumption that the argument rests on. Examples: I. Active euthanasia is morally acceptable. It is a decent, ethical thing to help another human being escape suffering through death. Premise: It is a decent, ethical thing to help another human being escape suffering through death. Conclusion: Active euthanasia is morally acceptable. II. Murder is morally wrong. 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 we’ll just focus on the uncontroversial premise, “Murder is morally wrong,” and not notice what is being assumed. 15. Equivocation  Is sliding between two or more different meanings of a single word or phrase that is important to the argument. Example: Giving money to charity is the right thing to do. So charities have a right to our money. The equivocation here is on the word “right”: “right” can mean both something that is correct or good and something to which someone has a claim. Sometimes an arguer will deliberately, sneakily equivocate, often on words like “freedom,” “justice,” “rights,” and so forth; other times, the equivocation is a mistake or misunderstanding. 16. Appeal to Popular Opinion  This sort of appeal is when somebody asserts that a thought or conviction is correct, since it is the thing that the general population accepts. Example: Lots of people purchased this collection, so it must be great.

17. Association Fallacy  Sometimes called “guilt by affiliation,” this happens when somebody connects a particular thought or issue to something or somebody negative, so as to infer blame on another individual. Example: Hitler was a veggie lover, so I don’t trust vegans. 18. Attacking the Person  Also regarded as “argumentum ad hominem” (argument against the man), this is a common fallacy used during debates, where an individual substitutes a rebuttal with a personal insult. Example: Don’t listen to Eddie’s contentions on teaching, he’s a simpleton. 19. Begging the Question

 The conclusion of a contention is accepted as a statement of the inquiry itself. Example: If the neighbor didn’t take my daily paper, who did? (This accepts that the daily paper was really stolen).

SYLLOGISM  Is a form of deductive reasoning where you arrive at a specific conclusion by examining two other premises or ideas. Syllogism derives from the Greek word syllogismos, meaning conclusion or inference.  It is a systematic representation of a single logical inference. Three components: 1. 2. 3.

Major Premise Minor Premise Conclusion

The major premise contains a term from the predicate of the conclusion The minor premise contains a term from the subject of the conclusion The conclusion combines major and minor premise with a “therefore” symbol (∴) When all the premises are true and the syllogism is correctly constructed, a syllogism is an ironclad logical argument. Example: Major premise: All roses are flowers. Minor premise: This is a rose. Conclusion: Therefore, I am holding a flower.

TYPES OF SYLLOGISM 1. Categorical Syllogism  Categorical syllogisms follow an “If A is part of C, then B is part of C”. Examples 1. All cars have wheels. I drive a car. Therefore, my car has wheels. Major Premise: All cars have wheels. Minor Premise: I drive a car. Conclusion: My car has wheels. 2. All insects frighten me. That is an insect. Therefore, I am frightened. Major Premise: All insects frighten me. Minor Premise: That is an insect. Conclusion: I am frightened. 2. Conditional Syllogism  Conditional syllogisms follow an "If A is true, then B is true". They're often referred to as hypothetical syllogisms because the arguments aren't always valid. Sometimes they're merely an accepted truth. Examples 1.

If Katie is smart, then her parents must be smart. Major premise: Katie is smart. Conclusion: Katie's parents are smart.

2.

If Richard likes Germany, then he must drive an Audi. Major premise: Richard likes Germany. Conclusion: He must like all things German, including their cars.

3. Disjunctive Syllogism  Disjunctive syllogisms follow a "Since A is true, B must be false" premise. They don't state if a major or minor premise is correct. But it's understood that one of them is correct. Major Premise: This cake is either red velvet or chocolate. Minor Premise: It's not chocolate. Conclusion: This cake is red velvet. Major Premise: On the TV show Outlander, Claire's husband is either dead or alive.

Minor Premise: He's not alive. Conclusion: Claire's husband is dead.

4. Enthymemes  An enthymeme is not one of the major types of syllogism but is what's known as rhetorical syllogism. These are often used in persuasive speeches and arguments.  Generally, the speaker will omit a major or minor premise, assuming it's already accepted by the audience. Examples 1. He couldn't have stolen the jewelry. I know him. Major Premise: He couldn't have stolen the jewelry. Minor Premise: I know his character. 2. Her new purse can't be ugly. It's a Louis Vuitton. Major Premise: Her new accessory can't be ugly. Minor Premise: It's made by famous designer Louis Vuitton.

In an enthymeme, one premise remains implied. In the examples above, being familiar with someone or something implies an understanding of them. 5. Syllogistic Fallacy  Some syllogisms contain false presumptions. When you start assuming one of the major or minor premises to be true, even though they're not based in fact - as with disjunctive syllogisms and enthymemes - you run the risk of making a false presumption. Examples 1. All crows are black. The bird in my cage is black. Therefore, this bird is a crow. Major Premise: All crows are black. Minor Premise: The bird in my cage is black. Conclusion: This bird is a crow. 2. The scenery in Ireland is beautiful. I'm in Ireland. Therefore, the scenery must be beautiful. Major Premise: The scenery in Ireland is beautiful. Minor Premise: I'm in Ireland. Conclusion: The scenery is beautiful. RULES OF SYLLOGISM  Six known rules of syllogism that will ensure in making a strong and accurate argument. 1. Rule One: There must be three terms: the major premise, the minor premise, and the conclusion no more, no less. 2. Rule Two: The minor premise must be distributed in at least one other premise.

3. Rule Three: Any terms distributed in the conclusion must be distributed in the relevant premise. 4. Rule Four: Do not use two negative premises. 5. Rule Five: If one of the two premises are negative, the conclusion must be negative. 6. Rule Six: From two universal premises, no conclusion may be drawn. VENN DIAGRAM CONCEPT 1: Some A is B Diagram

The possible conclusions are, 1. Some A is B 2. Some B is A

CONCEPT 2: Some A is B and Some B is C Diagram

Now the Possible Conclusions are Between A and B

Between B and C

Some A is B Some B is A

Some B is C Some C is B

There is no DIRECT CONNECTION between A and C. So it is not possible to derive any conclusion between A and C.

CONCEPT 3: All A is B Diagram

The Conclusions are All A is B Some A is B Some B is A

NOTE: when the statements are positive, the conclusions must be positive. CONCEPT 4: All A is B and All B is C Diagram

The Conclusions are: Between A and B

C A

Between B and C

Between A and C

All A is B Some A is B

All B is C Some B is C

All A is Some A is

Some B is A

Some C is B

Some C is

Concept 5: Some A is B. All B is C. Diagram

The possible conclusions are: Between A and B

Between B and C

Between A and C

Some A is B Some B is A

All B is C Some B is C Some C is B

Some A is C Some C is A

Concept 6: All A is B and Some B is C Diagram

The possible conclusions are: Between A and B

Between B and C

All A is B Some A is B Some B is A

Some B is C Some C is B

Note: There is no DIRECT CONNECTION between A and C. So it is not possible to derive any conclusion between A and C.

Concept 7: All B is A and All C is A Diagram

The possible conclusions are:

Between A and B

Between A and C

All B is A Some B is A Some A is B

All C is A Some C is A Some A is C

Note: There is no DIRECT CONNECTION between B and C. So it is not possible to derive any conclusion between B and C.

Concept 8: No A is B Diagram

The Possible Conclusions are: No A is B No B is A Some A is not B Some B is not A Note: When NO comes in Statement, Some-not should follow in Conclusion

Concept 9: All A is B and No B is C Diagram

The Possible Conclusions are: Between A and B All A is B Some A is B Some B is A

Between B and C No B is C No C is B Some B is not C Some C is not B

Between A and C No A is C Some A is Not C

Concept 10: All A is B and No A is C Diagram

The Possible Conclusions are: Between A and B All A is B Some A is B Some B is A

Between A and C No A is C No C is A Some A is not C Some C is not A

Between B and C Some B is not C

Concept 11: Some A is B. No B is C Diagram

The Possible Conclusions are: Between A and B

Between B and C

Some A is B Some B is A

No B is C No C is B Some B is not C Some C is not B

Concept 12: Some A is B: No A is C Diagram

Between A and C Some A is not C

The Possible Conclusions are: Between A and B Some A is B Some B is A

Between A and C No A is C No C is A Some A is not C Some C is not A

Between B and C Some B is not C

Note: In all the above, the conclusions are made based on the statements. There

are only one case where the conclusions are determined based on the conclusion itself. It is called as Merging Concept.

MERGING CONCEPT  This concept is applicable when more than one conclusion does not follows. Rules: 1. 2. 3. 4.

The two non-following conclusions must be of same character. One conclusion must be positive (All/Some) One conclusion must be negative (No/Some-not) Let me explain this concept with some examples.

Example 1 Statement: All Lotus are Flowers; No Lilly is Lotus. Conclusion: No Lilly is a flower; Some Lilly is Flowers. Diagram

Conclusions: I. II.

No Lilly is a flower. (It’s not true) Some Lilly is flowers. (It is also not true)

Note: Two conclusions are false. And both are same characters (Lilly and Flower). One is Positive and one is negative. It satisfies all the rules of Merging Concept. Thus, the Answer is either (I) or (II). Example 2 Statement: Some Cameras are Radios; Some Statues are Cameras. Conclusion: Some Radios are statues; No Radio is a Statue. Diagram

I. II.

Some Statues are Radios (It is false) (No direct relation between Statue and Radio) No Radio is a Statue (It is False) (It is a negative conclusion) (When statements are positive, conclusions must be positive).

Note: Two Conclusions are False. They are of same character. One is Positive and other is Negative. Thus, the answer is either (I) or (II) POSSIBILITY  Whenever the term “Possibility” OR “Can” comes in Conclusion, we need to check this simple table.

Explanation Statements:

Some Mangoes are Apples; Some Bananas are Apples; Some Branches are Bananas

Conclusions: Some Mangoes are Bananas Some Branches Being Apples is a Possibility Some Branches are Mangoes All Apples Being Mangoes is a Possibility Diagram

Conclusions 1. It is False. (No Direct Connection between them). II. No relation between Branches and Apples. “Possibility” is there. (It is True) III: It is False (No Direct relation) IV: Between Apples and Mangoes “Some” can come. “Possibility is there”. It is also true. Thus, either II or IV Important Rules: Draw Venn Diagrams (Basic Diagram & Possibility Diagram) according to the Statement.  If the conclusion does not satisfy the Basic Diagram then there is no need to check the possibility diagrams.  If the conclusion satisfies the Basic Diagram then it must satisfy all possibility diagrams.  The first Venn diagram in all images shown below are Basic Diagrams & remaining are Possibility Diagrams. 

All A are B:

Some A are B:

Some A are not B:

Examples Statements: All Circles are Squares. Some Squares are Roses Conclusion 1: Possibility Diagram

Conclusion 2: Possibility Diagram

Conclusions: I. All Roses being Square is a possibility II. Can all Circles be Roses Both (I) and (II) follow

NEGATIVE AND POSTIVE SYLLOGISM BASED ON PALALI CASE: NEGATIVE Major Premise: Minor Premise: Conclusion: EXPLANATION:

Certificate of Land Title is the only evidence of ownership of real property. Tax Declaration is the only evidence of the petitioner over the subject matter. Therefore, Petitioner has no proof of evidence of ownership over the subject matter. The conclusion of a standard form categorical syllogism is negative, but both of the premises are positive or drawing a negative conclusion from affirmative premises.

POSITIVE Major Premise:

Strong evidence of ownership is the only way to convince the court of better right to subject property.

Minor Premise:

Petitioner was able to prove his and his predecessor’s actual, open, continuous and physical possession of the subject property.

Conclusion:

The preponderance of evidence is therefore clearly in favor of petitioner, as the actual possessor under claim of ownership.

EXPLANATION:

A positive premise requires a positive conclusion, and a positive conclusion requires a positive premise.

THE IMPORTANCE OF SYLLOGISMS Syllogisms represent the strongest form of logical argument. Like triangles in architecture, the syllogism is the strongest logical structure. When formed correctly, they are indisputable in terms of their logical validity. However, it’s important to remember what syllogisms don’t do, they don’t prove their own premises and it could build an argument out of very strong syllogisms, but it wouldn’t work if its original premises weren’t correct. Thus, it has to ensure that the starting point of the argument is solid, or no amount of syllogisms will make the argument successful as a whole. HOW TO WRITE A SYLLOGISM 1. Start with the conclusion. Most of the time, writing a syllogism as a way of laying out the steps in the argument that already worked out for easily start with the conclusion. The most important part of the syllogism is the part that were trying to prove through logic. Example: Although most have live young, some mammals lay eggs. 2. Break the conclusion down into subject and predicate. The grammar of the conclusion will dictate the logical structure of the syllogism use to support it be able to recognize subject and predicate in the sentence. Example: Although most have live young, some mammals (subject) lay eggs (predicate) 3. Locate the key terms. Take the subject and predicate, and boil them down to their key terms. Get rid of unnecessary adjectives and other extraneous words, and just focus on the word or words that carry the weight of the sentence. Example: Mammals lay eggs 4. Craft your premises. Remember that the major premise will contain the key terms of the predicate, while the minor premise contains the key terms of the subject. Craft separate sentences around these key terms such that they fit together into a syllogism. Examples:

Echidnas are mammals (minor premise) Echidnas lay eggs (major premise)

5. Check whether the conclusion follows from the premises. Can you make a persuasive “if…then” statement using your premises to prove your conclusion? If not, the syllogism is not logically structured and will not work in your argument. Example: If echidnas are mammals and echidnas lay eggs, then of

course it follows that some mammals must lay eggs. 6. Check whether the premises are persuasive. If you think the reader will accept both premises, and the syllogism is logically sound, then this step in your argument will be beyond criticism. However, bear in mind that a skeptical reader will often find ways to doubt your premises, so don’t take them for granted! Example:

Echidnas are mammals (persuasive because of scientific consensus) Echidnas lay eggs (persuasive because of empirical observation)

WHEN TO USE A SYLLOGISM Syllogisms are very abstract representations, and are rarely not seen outside of formal logic and analytic philosophy. In other fields, it’s probably best not to write the syllogism out as part of the paper. However, it can still be very useful as a mental exercise even if it does not end up showing the whole syllogism to the reader, it can be written it out on scratch paper as a way of evaluating own argument. EXAMPLES IN PHILOSOPHY AND LITERATURE Ambrose Bierce famously satirized the syllogism form in his Devil’s Dictionary: 60 men together can work 60 times as quickly as one man alone. One man alone can dig a hole in one minute. Therefore, 60 men can dig a hole in one second. Each step in this syllogism seems to make sense, and the syllogism itself is logically sound. But the conclusion is clearly wrong because premise #1 is deceptive. In theory it’s true that 60 men can work 60 times as fast as one. But in practice things are not so simple, as Bierce’s clever example shows. Aristotle invented the example in #2, the one about Socrates being mortal. But he also used another example to demonstrate how a valid syllogism could produce a false conclusion if based on faulty premises (despite the syllogism itself being logically valid). Everything white is sweet Salt is white Therefore, salt is sweet. Clearly, premise #2 is wrong, and the conclusion is wrong as well. But if premise #2 were correct, then the conclusion would be correct as well. That means the syllogism is logically valid though factually incorrect. EXAMPLES IN POPULAR CULTURE

It can be fun to locate and critique the hidden syllogisms in the world around us. In advertising, for example, there is always a hidden syllogism with “therefore, you should buy our product” as its conclusion. For example, many liquor ads are based on the following syllogism: Women like men who buy this brand of alcohol. You are a man and you want women to like you. Therefore, you should buy this brand. There are many potential problems with this argument, but the most obvious one is that it probably has at least one false premise. Women probably don’t truly prefer men who purchase that particular brand. In addition, the viewer may well be a woman or a gay man, in which case the other premise is also false. That’s a faulty syllogism. Just because you call Bill a dog doesn’t mean he is a dog.” In one episode of House, the title character refers to a “faulty syllogism” in a way that’s not entirely clear. But the syllogism he’s referring to looks like this: I call Bill a dog. Things are whatever I call them. Therefore, Bill is a dog. The syllogism is clearly faulty because premise #2 is false.