Classic Flaws and Common Loopholes

Dangling variables

Common Loophole

New words that appear in the conclusion but not the premises

Loophole: what if those two things are not necessarily the same?

Good for SA questions, because your SA can connect the dangling variable with a variable seen in the premises

Diets high in cholesterol have been shown to contribute to a variety of health issues, including high blood pressure. Therefore, the western diet may contribute to heart issues experienced by many Americans.

Dangling variable example

The conclusion equates diets high in cholesterol with “the western diet.”

Conditional dangling variables

Common Loophole

Like regular dangling variables, but for stimuli with conditionals. These add a new variable to the conclusion’s conditional statement

Often occurs when your premises create a conditional chain. The conditional dangling variable then adds an extra term to the end of the chain not established by the premises.

Loophole: What if you can’t stealth add the new variable on the end of the chain?

Whenever one establishes a dictatorship, one inevitably prefers the water. Preferences for the aquatic must be followed in dictatorship site selection. Therefore, dictatorships always reside in the Bay of Pigs

Conditional dangling variable example

The premises establish that: establish dictatorship → prefer water → follow preferences in site selection

However, the conclusion adds on a “→ Bay of Pigs” at the end of the premises’ conditional chain

There can be other aquatic sites available for site selection that would fulfill the dictatorship’s preferences.

Secret value judgement

Common Loophole, type of dangling variable

When the author makes a value judgement in the conclusion without defining the value judgement thoroughly in the premises

Common secret value judgements: good/bad, moral/immoral, right/wrong, appropriate/inappropriate, should/shouldn’t, prudent/imprudent

Loophole: What if the issue/item at hand does not equate to the secret value judgement?

A fundamental illusion in robotics is the belief that improvements in robots will liberate humanity from hazardous and demeaning work. Engineers are designing only those types of robots that can be properly maintained with the least expensive, least skilled human labor possible. Therefore, robots will not eliminate demeaning work - only substitute one type of demeaning work for another.

Secret value judgement example

Demeaning work is equated with the “least expensive, least skilled human labor” without proper establishment in the premises

Secret downsides

Common loophole

When the author compares two things and says one of them is superior without giving you the full story. They might say their preferred choice has a few upsides, or that the unpreferred choice has a few downsides. However, not giving you all the upsides and downsides

Loophole: What if the argument’s preferred option has a big downside?

The program would benefit if Dolores takes Victor’s place as director, since Dolores is far more skillful than Victor is at securing the financial support the program needs and Dolores does not have Victor’s propensity for alienating the program’s most dedicated volunteers

Secret downsides example

What if Dolores is so much worse than Victor at everything else?

Assumed universal goals

Common loophole

Things that the author just assumes everyone would want. You can NEVER assume that it’s common knowledge for everyone to want one of these goals

Common assumed universal goals: losing weight, lowering cholesterol, making more money, being healthier, being more successful

Loophole: What if they don’t want to [assumed universal goal]?

Western diets commonly include foods high in fats and cholesterol. For this reason, those living in western countries should consume less of these high-cholesterol foods.

Assumed universal goal, assumes everyone wants to lower cholesterol

Bad conditional reasoning

Classic flaw

The author reads conditionals incorrectly. Often, this involves negating the conditionals without flipping them OR flipping the conditionals without negating them.

Loophole: what if we actually have to follow the rules of conditional reasoning?

Unplugging a peripheral component such as a “mouse” from a personal computer renders all of the software programs that require the component unusable on that computer. On Fred’s personal computer, a software program that requires a mouse has become unusable. So it must be that the mouse for Fred’s computer became unplugged

Bad conditional reasoning LSAT example

Premises establish that: unplug→unusable

Conclusion claims that: unusable→unplug

Wrong, because there are other reasons why a program could become unusable besides unplugging the mouse

Everyone named James wears a blue shirt. Wearing a blue shirt inevitably results in owning a red car. Therefore, if you are not named James, then you do not own a red car.

Bad conditional reasoning

premises establish that: named James → wear blue shirt → own red car

Conclusion claims that: ~James → ~own red car

Wrong, because we don’t know anything about people not named James (the premises do not establish anything regarding that). Maybe all people named Jack must also own red cars (meaning that the conclusion is wrong). The only thing we do know is that if you don’t own a red car, you cannot be named James.

Bad causal reasoning

Classic flaw

Occurs when the author sees that two variables are correlated and then concludes that these two things must have a causal relationship.(X and Y are correlated. Therefore, X causes Y)

Vast majority of causal conclusions on the LSAT are bad.

Loophole: what if one of the omitted options is the case?

Omitted options:

• Backwards Causation (What if Y causes X?) - this doesn’t work, however, if Y is established as chronologically occurring after X in the premises

• No relationship (What if Y can occur without X? What if X occur without Y following? What if the study, survey, experiment, or situation was flawed?)

• New factor causing one or both (What if Z causes Y? What if Z causes both X and Y to occur?)

Chronic fatigue syndrome, a condition that afflicts thousands of people, is invariably associated with lower-than-normal concentrations of Mg in the blood. Further, malabsorption of Mg from the digestive tract to the blood is also often associated with some types of fatigue. These facts in themselves demonstrate that treatments that raise the concentration of Mg in the blood would provide an effective cure for the fatigue involved in the syndrome

Bad causal reasoning example, LSAT

Premises use the word “associated,” meaning low Mg concentration is correlated with fatigue. However, the conclusion uses the word “effective cure,” meaning that it is assuming a causal relationship (low Mg causes fatigue)

However, cannot just extrapolate from purely correlative data to make a causal conclusion. What if something else like malnutrition is causing both low Mg and fatigue?

Various studies have shown that consuming foods high in sodium is correlated to weight gain. Therefore, those looking to prevent weight gain should consider consuming foods that are low in sodium.

Bad causal reasoning

Premises establish a correlation, while the conclusion assumes a causal connection. What if a third factor is the cause of both?

Whole to part and part to whole

Classic flaw

When someone claims that because the parts of a category have a characteristic, the category itself must have that characteristic. (or vice versa)

Loophole: What if wholes don’t necessarily equal parts?

Each of the elements of Girelli’s recently completed design for a university library is copied from a different one of several historic libraries. The design includes several features from Classical Greek, Islamic, Mogul, and Romanesque structures. Since no one element in the design is original, it follows that the design of the library cannot be considered original

Whole to part/part to whole, LSAT example

Just because the individual design elements are not original, doesn’t mean the entire library cannot be original. The composition of the elements, the layout, etc. can all be unique.

All members of the school robotics team are individually very logical and reasonable. It follows that the school robotics team will, as a whole, perform logically and reasonably.

Whole to part/part to whole example

Although all members are logical and reasonable, it is possible that when put together, they will act illogically as a team.

Overgeneralization

Classic flaw

When the author concludes that because something has a property, a bunch of other things also possess that property

Think of as a part-to-part generalization. Usually generalizing something that is part of a spectrum to everything on that spectrum. Can also generalize a part of a category to all the parts of the category

Loophole: What if we can’t generalize from this one thing to a bunch of other things?

Those economists who claim that consumer price increases have averaged less than 3 percent over the last year are mistaken. They clearly have not shopped anywhere recently. Gas is up 10 percent over the last year; my auto insurance, 12 percent; newspapers, 15 percent; propane, 14 percent; bread, 50 percent.

Overgeneralization, LSAT example

You are overgeneralizing facts about bread and propane to apply to all consumer prices

Not whole to part or part to whole because the person doesn’t claim that all consumer prices are increasing. Just that a select few consumer prices are increasing. The author then attempts to generalize that because some prices are rising, the price of other things are also rising. Thus, all prices are rising above 3%.

Cassandra is a comedian who excels in writing knock-knock jokes. Thus, she will likely excel in writing any kind of material

Overgeneralization

Survey Problems

Classic flaw

Usually surveys in the LSAT have many issues. These include: biased samples, biased questions, small sample size, survey liars, and other contradictory surveys

Unless the stimulus specifically accounts for these errors, you can use these flaws against the stimulus

Loophole: What if [any of the survey flaws]?

False starts

Classic flaw

If there are two groups that are being compared, the author often assumes that the two groups are equal in all other aspects except the thing being compared.

Most common for studies with two groups. However, unless the stimulus specifically accounts that the group is similar in all relevant aspects except the factor being tested, you can use this loophole

Loophole: what if the two groups were actually different in a key respect?

Possibility does not equal certainty

Classic flaw

When the author equates the lack of evidence for something being true/false to proof that something cannot be true/false. OR when the author equates the possibility that something is true/false to proof that something must be true/false

The first case is illustrated by: lack of evidence does not equal evidence of lacking

The second is illustrated by: proof of evidence does not equal evidence of proof

Turn the above phrases into the loophole

Despite the best efforts of astronomers, no one has yet succeeded in exchanging messages with intelligent life on other planets or in other solar systems. In fact, no one has even managed to prove that any kind of ET life exists. Thus, there is clearly no intelligent life anywhere but earth

Possibility does not equal certainty, LSAT example

Just because there is a lack of evidence for ET intelligent life doesn’t mean there cannot be ET intelligent life

Scientists have discovered some evidence that frequent heartburn leads to esophageal cancer. Therefore, frequent untreated heartburn results in cancer.

Possibility does not equal certainty

Implication

Classic flaw

When the author mixes fact with belief/opinion. This often occurs when discussing the implications of someone’s opinion. Even though someone’s opinion may relate to a fact, you cannot prove that the person is aware of that fact.

Loophole: What if the person isn’t aware of what their belief implies?

Bank deposits are credited on the date of the transaction only when they are made before 3 pm. Alicia knows that the deposit was made before 3 pm. So, Alicia knows that the bank deposit was credited on the date of the transaction.

Implication fallacy, LSAT example

Alicia may not know the policy that the bank has about crediting transactions dates only when made before 3 pm

Also some bad conditional reasoning (premises establish: credited on date → made before 3 pm. however, conclusion claims: made before 3 pm → credited on date)

Lily thinks that eating fish is good for the heart. Fish is good for the heart because it contains a wealth of omega-3 fatty acids. Thus, Lily knows that omega-3 fatty acids are good for the heart.

Implication fallacy

We don’t know if Lily knows why fish is good for the heart

False dichotomy

Classic flaw

The author pretends that there are only two options when there could be more. The author then eliminates one of the options and concludes that the second option must be the case

Two ways:

• Limiting a spectrum - there are actually three ways to change on a spectrum (up, down, unchanged). the author will pretend that there are only two ways (usually just up and just down). Just remember: not more does NOT equal less, and not less does NOT equal more

• Limiting options - pretends there are only two options when there could be more

Loophole: what if there are more than two options?

Also, if on a parallel flaw question, note that there is a difference between limiting options and limiting a spectrum (they are technically different flaws, even though both are classified as a false dichotomy)

Because of teacher hiring freezes, the quality of education in that country will not improve. Thus, it will surely deteriorate

False dichotomy, LSAT example

Limiting a spectrum

Because Raoul is a vegetarian, he will not have the pepperoni pizza for lunch. It follows that he will have the cheese pizza.

False dichotomy, LSAT example

Limiting options

Tonya must be mad at me. The fact that she hasn’t responded to any of my messages shows that she cannot be happy with me.

False dichotomy

The question pretends to limit the options to: Tonya mad or Tonya happy. Because she cannot be happy, she must be mad. However, it’s also possible that she is busy, or she is too sad, etc.

Straw man

Classic flaw

When the author misrepresents someone else’s point in order to make it easier to refute

Often see it preceded by phrases like: “So what you’re saying is…” or “so what you mean is…”

Loophole: What if what they said has nothing to do with the claim they’re pretending to respond to?

Student rep: Out university, in expelling a student who verbally harassed his roommate, has erred by penalizing the student for doing what he surely has a right to do: speak his mind!

Dean: but what you’re saying is that our university should endorse verbal harassment. Yet surely if we did that, we would threaten the free flow of ideas that is the essence of university life

Straw man, LSAT example

The dean misrepresents the student rep’s point, making the argument sound absurd

A: Those who cry about the degradation of free speech on the internet tend to forget one crucial fact. Namely, free speech does not mean freedom from consequences. You are free to say anything you like on social media, but you must be prepared for the backlash associated with disseminating controversial ideas

B: So what you mean is that bullying and harassing people for expressing their ideas online is ok. This would prevent people from exercising their right to free speech in the first place, thus violating the right to free speech.

Straw man example

Ad hominem

Classic flaw

When someone challenges the truth of an argument/position by attacking the character/motives of the person pushing that argument/position.

Remember that a person’s motivation or character has NO effect on the truth/falsity of a claim/conclusion. Only the premises and structure of the argument have this effect.

Premises about character, motivation, and bias ONLY prove claims about character, motivation, and bias

Loophole: What if this person’s character/motivation doesn’t affect the truth?

Many of my customers find that their physical coordination improves after drinking juice containing certain herbs. A few doctors assert that the herbs are potentially harmful, but doctors are always trying to maintain a monopoly over medical therapies. So there is no reason not to try my herb juice.

Ad hominem, LSAT example

Professor Smith defines good behaviors as behaviors that are reasonably expected to result in the maximum possible increase in well being for the maximum possible population. However, Smith is an unsuccessful philosopher whose research into well-being and morality have been rightfully dismissed by the broader academic community. Thus, Smith’s definition of good behaviors should be ignored.

Ad hominem

Circular reasoning

Classic flaw

When the author assumes the conclusion is true without doing the work of proving it so. Often, will rule out objections to the conclusion because they assume the conclusion must be true.

Not super easy to spot sometimes, as authors will use different language to express the same idea. But if you feel like the premises and conclusions are repeating the same general idea, look to see if circular reasoning is at play

Loophole: what if we can’t use the conclusion as evidence for itself?

Many people do not understand themselves, nor do they try to gain self understanding. These people may try to understand others, but these attempts are sure to fail, because without self understanding, it is impossible to understand others. It is clear from this that anyone who lacks self understanding will be incapable of understanding others.

Circular reasoning, LSAT example

The premises and conclusion almost repeat each other, and the conclusion relies on the fact the premises essentially restate exactly what the conclusion says.

Excess fabric left over from projects is useless. This is because no one wants to use excess fabric, as it presents no other opportunities for application to other projects or uses.

Circular reasoning example

Equivocation

Classic flaw

When the author changes the meaning of a word throughout an argument

Loophole: What if we shouldn’t let words change in meaning?

Our management consultant proposes that we reassign staff so that all employees are doing both what they like to do and what they do well. This, she says, will “increase productivity by fully exploiting our available resources.” But our company has a long-standing commitment not to exploit its workers. Therefore, implementing her recommendations would cause us to violate our own policy

Equivocation, LSAT example

The word “exploit” is being used to mean two different things here. The first meaning is more neutral, just meaning to use to the fullest extent. The second meaning carries a negative connotation, meaning to take advantage of something/someone.

Critics have accused our apparel brand of lifting ideas from small, independent designers. But our brand has always greatly valued these smaller artists. Criticizing us for lifting up their designs and exposing their ideas to a global market is absurd.

Equivocation example

Appeal fallacies

Classic flaw

When the author turns someone’s opinion into fact. This occurs as either:

• Invalid appeal to authority - when you take a non-expert’s word as fact

• Invalid appeal to public opinion

You can take an expert’s opinion as fact AS long as the topic is about what the expert’s expertise is about

Loophole: what if this opinion doesn’t equal evidence of fact?

Basically, never jump from opinion to fact or fact to opinion UNLESS you have a real expert to back it up

Most people believe that yawning is most powerfully triggered by seeing someone else yawn. This belief about yawning is widespread not only today, but also in the past. Thus, seeing someone else yawn must be the most irresistible cause of yawning

Appeal fallacy, LSAT example

The first sentence, a premise, states the same thing as the conclusion. However, the premise is an OPINION, and the conclusion states it as fact

Various classical music experts believe that the music industry’s continued focus on genres like pop will negatively affect music sales in the future. The music industry should avoid focusing on genres that will negatively affect its future sales. Thus, the music industry should pivot focus away from genres like pop.

Appeal fallacy

Classical music experts are not experts in general music sales

Irrelevant

Classic flaw

When the premises are entirely unrelated to the conclusion. Technically, many classic flaws are irrelevant to some extent. However, only choose this if you cannot find any other flaws

Loophole: What if the premises and conclusion have nothing to do with one another?

Office manager: I will not order recycled paper for this office. Our letters to clients must make a good impression, so we can’t print them on inferior paper

Supplier: Recycled paper is not necessarily inferior. In fact, from the beginning, the finest paper has been made of recycled material. It was only in the 1850s that the paper began to be made from wood fiber, and then only because there were no longer enough rags to meet demand for paper

Irrelevant

The fact that recycled paper was good in the past does not refute the claim that the recycled paper held by the supplier in the modern day is inferior

Recent student protests that the dress code is archaic are incorrect. Compared to the restrictions of some other schools in the state, our school dress code is equally restrictive with regards to enforcement and rules. Furthermore, with regards to policies about skirt/short lengths, our dress code allows for far more leniency than some of these other schools

Irrelevant

How restrictive the dress code of the school is compared to other modern schools is irrelevant to the claim that the code is archaic

Percentages do not equal numbers

Classic flaw

When the premises are about numbers, and the conclusion is about percentages. Or vice versa. This is almost always wrong, because you must assume that the overall group size remains the same. If the stimulus does not explicitly establish this, you cannot reasonably make this assumption.

Loophole: what if the group size doesn’t remain the same? OR what if the two compared groups are different sizes? OR what if percentages do not equal numbers/amounts?

A commonly accepted myth is that left handed people are more prone to cause accidents than are right handed people. But this is, in fact, just a myth, as is indicated by the fact that more household accidents are caused by right handed people than are caused by left handed people

Percentages do not equal numbers

Conclusion is about how “prone” one group is to accidents. This is a percentage. Premise is about the amount/number of accidents by a certain group

Gloria sold 20 more cakes than she did yesterday. Thus, Gloria’s share of the cake market in her city increased from yesterday’s share.

Percentages do not equal numbers