## Flaws: PowerScore’s Chapter on Causation

There are many LSAT questions that involve causal reasoning, which is significantly different from the conditional reasoning that makes up most of the rest of the test. PowerScore’s Logical Reasoning Bible squeezes in a chapter on causal reasoning between the chapter on “weakening arguments” and “strengthening arguments.” There’s a reason for that–a statement which might a perfectly valid conditional statement (“if the rooster crows, then the sun comes up”) could be a ridiculous causal claim (“the rooster crows, which causes the sun to come up”).

PowerScore identifies five situations which weaken a causal relationship. I have taken the liberty of turning them into an acronym:

• R: Reverse causation
• A: Alternate cause
• C: Cause without effect
• E: Effect without cause
• S: Statistical errors

Let’s run through these, using our rooster example. Perhaps the rooster does not cause the sun to come up–instead, it is the early morning sunlight that causes the rooster to crow. That would be a clear case of reverse causation.

The problem with that explanation, as any chicken keeper knows, is that roosters start crowing long before the sky begins to get light. Maybe there is some kind of biological clock inside the rooster that tells it that 24 hours have passed. If so, that would be an alternate cause–something other than the sun itself that causes the effect.

If we wanted to prove that the rooster doesn’t really make the sun come up, we just need to get the rooster to crow in the middle of the night and see what happens. This happens to me now and then when we start something time consuming right around sunset. I have to grab my flashlight and go close up the chickens late at night. My roosters start crowing their heads off when I turn on the lights, and the sun stays put.  It’s hard to have a causal relationship if you you can have the “cause” (the rooster crowing) without the “effect” (the sun coming up). That’s a cause without effect situation.

Most of my students don’t even keep chickens–which means the sun comes up on them even though no rooster crowed.  That is an effect without cause situation.

PowerScore’s final category involves statistics. When we say, “The rooster crows and the sun comes up,” we oversimplify the situation. My roosters crow pretty much all day long. (That’s why we keep them well away from the house!) If we graphed all the times each rooster crows and plotted it against the sunrise, it would be obvious that the rooster has nothing to do with the sunrise. The reason I associate sunrise with roosters is that when those noisy birds wake me up I want to go make rooster soup! If I’m already awake, I just ignore their crowing. If I had good data instead of my very selective memory, I would never associate crowing with sunrise.

## Flaw Questions and Bird-Watching

More students get more flaw questions wrong than anything else. (That’s because flaw questions are hard for many people, flaw answers are hard for most people, and there are lots of flaw questions on every test.) Every LSAT curriculum includes a chapter on flaws, but nothing that I have seen in print will enable a student to dramatically improve on flaw questions. That’s a pity, because flaws–more than any other question type–can be conquered with sufficient time and effort.

I want all my students to get every flaw question right every time. To achieve that goal, I start with the answer choices. Every LSAT flaw question has five different answers, and the overwhelming majority of those answers describe specific errors that any student can learn to identify with a little help and a lot of practice.

It’s a little like bird-watching. Here’s an example:

There’s a bird at my bird-feeder. It’s small bird, all black, gray, and white. There’s some white on its cheeks  but the top of its head and the underside of its chin is black.  I see plenty of them every winter, but the only time I’ve seen one in summer was up in Maine.

Most readers can probably rule out a cardinal instantly, but the rest of the options are harder. Most readers are going to have to click the hyperlinks to look at the pictures before they can identify this bird. But once you know exactly what these five birds look like, it’s (fairly) easy to pick the right one from the list.

Once you know your flaws, you can eliminate wrong answers in a hurry.  In our bird example above, only two of those five birds are white and gray and black. One of the others is a dark gray and white, but there’s no white on the head so it isn’t an option. Of the two that really are white and gray and black, one is migratory and the other isn’t. Any decent bird-watcher could pick the right answer in about five seconds without ever needing to click on a hyperlink. I want you to be that fast (and that accurate) on flaw questions.

## Flaws: Volume V Flaws

The following work-in-progress is a hyperlinked list of the ANSWERS to flaw questions in “10 Actual Official LSAT Preptests Volume V.” This document should immediately increase your accuracy on flaw questions by explaining what each answer means. If you carefully study the different flaws and the words the LSAT authors use to describe it, you should be able to get more right answers in less time in the LSAT logical reasoning section,

62-2-5: Childhood lead poisoning (p. 17)

1. Statistical errors
2. Circular reasoning
3. Overlooked possibility
4. Assumption
5. Assumption

62-2-7: Flawed parallel pattern (p. 17) is fallacy of division

62-2-8: Space exploration (p. 18)

62-2-11: Athlete’s foot (p. 19)

1. “Can cure” does not equal “always cures”
2. Survey problem
3. Assumption
4. Overlooked possibility
5. Assumption

62-4-9: Parallel flawed pattern (p. 30) is “if a husband is right-handed, the wife is probably right-handed; so if the wife is left-handed, the husband is probably left-handed.”

62-4-10: Moon of Jupiter (p. 30) [THIS NEEDS WORK!]

1. Assumption (that a “necessary” condition is always necessary–this assumption is always true!)
2. Overlooked possibility
3. Assumption
4. Overlooked possibility
5. Assumption

62-4-

1. X

62-4-

1. X

62-4-

1. X

62-4-

1. X

## Flaws: Logical Reasoning’s Biggest Challenge

Most of my students with 7Sage.com accounts quickly discover that their highest study priority in logical reasoning should be “flaw” questions. With seven or more flaw questions per test and five confusing answers per question, most students will spend at least six minutes on LSAT day just trying to figure out what those flaw answers are supposed to mean. Every answer you don’t recognize consumes time, adds stress, and increases your odds of picking the wrong answer.

Students can improve both speed and accuracy by learning how to quickly and accurately recognize what the different flaw answer choices mean. The faster you can dismiss a wrong answer, the faster you can find the right answer and move on. A student who can quickly identify the wording used to describe common flaws should gain enough time to do at least two more questions in each logical reasoning section–and may be able to get more of the flaw questions right in the process. That can raise your score on test day significantly!

I have asked many students to study these flaw answer choices on  their own–with disappointing results. If you don’t know what the various flaws are, it’s really hard to figure out what these answer choices mean.  I have yet to find a commercially available LSAT text that enables the average student to quickly, confidently, and accurately identify the different answer choices.

They say it is better to light a single candle than to curse the darkness, so this series of posts is my attempt to light the way for a new generation of law students. I hope to identify every flaw answer choice in every “10 Actual Official LSAT Preptest” book. Here’s what I’ve done so far:

## Flaws: Mistaken Negation (TM)

PowerScore has trademarked a remarkable number of terms that have become standard LSAT jargon, including the term “Mistaken Negation (TM).” This logical error was identified more than two thousand years before PowerScore trademarked the name, however. Aristotle listed “denying the antecedent” as one of the thirteen original fallacies. Whatever we call this error, it shows up whenever you find this pattern:

• If you live in Detroit, you live in Michigan
• Therefore, if you don’t live in Detroit, you don’t live in Michigan.

This error is obvious when you use an intuitive example involving geography, but it is less obvious in other contexts. Don’t let that keep you from looking for it every chance you get–this little error is easy to slip into an argument and hard for the untrained eye to spot. That means you’ll see lots of these errors in easy-to-medium flaw questions.

You’ll see this answer choice often, but it may be the hardest answer to make sense of. The LSAT writers often use abstract terms that tend to paralyze the student. While it is possible to decode these baffling answers and demonstrate that they describe a “mistaken negation (TM),” it is very hard to do that with the clock ticking and your future on the line. That’s why it is so important to learn to identify this and other flaw answers before test day.

Here are some examples of answers that describe this particular flaw. (These are not actual LSAT answers, due to copyrights, but they are inspired by and similar to real answers):

• “It treats a sufficient condition for an argument’s conclusion to be a necessary condition for that conclusion.”
• “Takes a sufficient condition to be a necessary condition.”
• “Mistakes something that is sufficient to make an argument invalid for something that is necessary to make that argument invalid.”

Basically, these answers all indicate that somebody confused a sufficient condition for a necessary condition. That sounds a lot like a “mistaken reversal (TM)” (which is what happens when you confuse a necessary condition for a sufficient condition), but it is different. If you think a condition is necessary, then not having that condition means you can’t have the other condition.  Here’s how that works out:

• If you live in Detroit, you live in Michigan (true)
• If you live in Michigan, you live in Detroit (false–you confused the necessary term for a sufficient term)
• If you don’t live in Detroit, you don’t live in Michigan (false–you confused the sufficient term for a necessary term by saying what would happen if you didn’t have that term)

## Flaws: Mistaken Reversal (TM)

PowerScore has trademarked a remarkable number of terms that have become standard LSAT jargon, including the term “Mistaken Reversal (TM).” This logical error was identified more than two thousand years before PowerScore trademarked the name, however. Aristotle listed “affirming the consequent” as one of the thirteen original fallacies. Whatever we call this error, it shows up whenever you find this pattern:

• If you live in Detroit, you live in Michigan
• Therefore, if you live in Michigan, you live in Detroit.

This error is obvious when you use an intuitive example involving geography, but it is less obvious in other contexts. Don’t let that keep you from looking for it every chance you get–this little error is easy to slip into an argument and hard for the untrained eye to spot. That means you’ll see lots of these errors in easy-to-medium flaw questions.

You’ll see this answer choice often, but it may be the hardest answer to make sense of. The LSAT writers often use abstract terms that tend to paralyze the student. While it is possible to decode these baffling answers and demonstrate that they describe a “mistaken reversal (TM),” it is very hard to do that with the clock ticking and your future on the line. That’s why it is so important to learn to identify this and other flaw answers before test day.

Here are some examples of answers that describe this particular flaw. (These are not actual LSAT answers, due to copyrights, but they are inspired by and similar to real answers):

• “It mistakes a situation that must be present to establish the validity of the conclusion for a situation that would guarantee the validity of the conclusion.”
• “It treats a requirement for a pig to fly as something that ensures that a pig will fly.”
• “It takes a necessary condition for an argument’s failure to be a condition that would guarantee the argument would fail.”
• “Concludes, from the fact that X occurred and that Y would ensure that X occurred, that Y must have occurred.”

In most cases, the answer simply states that somebody has mistaken a necessary condition for a sufficient condition. Until you become familiar with the underlying problem and the way the LSAT writers word these “mistaken reversal (TM)” answers, these can be baffling. After you recognize the problem and the pattern, they become quite simple.

## Flaws: Assumption

When a “flaw” answer to an LSAT logical reasoning question contains words like “takes for granted” or “presumes, without justification,” you are dealing with an assumption of some kind. When you assume something that is necessary to the argument, you are definitely engaging in flawed reasoning. (As the old saying goes, “When you assume, you make an ass of u and me.”) Not every assumption is a necessary assumption, however, so the challenge is to discern whether this particular assumption is essential to this argument.

If an assumption is truly necessary, the argument self-destructs if you assume the logical opposite. Thus, for example, if I say, “Tuna is Marcia’s favorite lunch, so she is going to love my solid white albacore salad,” you have to assume that “albacore” is a kind of tuna. If you assume that albacore is not a type of tuna, the whole argument falls apart. You can always determine whether an assumption is truly necessary by seeing what happens when you assume its opposite.

This is why “extreme” statements are so seldom truly necessary assumptions. If I make an extreme assumption (for example, “solid white albacore is the only type of tuna”), then the logical opposite of that assumption generally won’t contradict the conclusion. Thus, if I assume that there other types of tuna besides albacore, my wife may still love her lunch.

That doesn’t mean that extreme answers are always wrong, however! You should check an extreme answer by assuming the logical opposite, and then see what effect that has on the argument. If an extreme answer is the right answer, assuming the opposite makes the argument fall apart. If it is the wrong answer, the opposite assumption has no real impact on the argument as a whole.

(It takes a little training to properly negate a logical statement. The logical opposite of “white” is not “black,” as you might suppose, but “not white.” Thus, pink, green, or tangerine are equally the opposite of white (in a logical sense). 7Sage.com has this post on how to find the logical opposite.)

## Flaws: Overlooked Possibility

There’s something wrong with your thinking when you “overlook the possibility” or “fail to consider” something. That’s why these phrases show up so often in “flaw” questions in the logical reasoning section of the LSAT.  (There are an average of 7 “overlooked possibility” answers per test.) You’ll see the same sort of answers on “weaken the argument” questions, with one little difference. The right answer to a weaken question may say, “There is more than one type of tuna.” The right answer to a flaw question may say, “Fails to consider that there is more than one type of tuna.” It is the failure to consider this possibility that turn it into a case of “flawed reasoning.”

The most reliable way to work through any overlooked possibility answer is to use what I call “JY Ping’s Unless Test.” This can  be found in the 7Sage LSAT curriculum. I have been informed by my students that JY Ping, who is one of God’s gifts to aspiring law students everywhere, suggests that you sort out a “weaken” stimulus into its evidence and conclusion and then read it out as follows:

• BECAUSE [evidence]
• THEREFORE [conclusion]

Thus, we might see a question like this:

• BECAUSE My wife loves tuna for lunch
• THEREFORE She will love this solid white albacore tuna salad
• UNLESS There is more than one type of tuna

(Note: there is more than one type of tuna and, no, Marcia doesn’t love solid white albacore!)

As you work through flaw questions with a “fails to consider” or “overlooks the possibility” answer, say the word “unless” and then read that answer off to yourself. If this doesn’t immediately and always get you the right answer, spend a little time on that question to see whether this technique will work for you. Leave a comment if it doesn’t help you on a particular question and I’ll see what I can do to make this clearer!

## Flaws: Mistaken Most

“Most” is a common and dangerous word on the LSAT. I routinely tell students that “‘most’ is mostly wrong” because there are so many easy ways to write a wrong answer using “most.” It is no wonder, then, that one of the most common parallel flaw patterns is the “mistaken most.” Here are some examples:

Most mammals have four legs.
All dolphins are mammals.
THEREFORE most dolphins have four legs.

Most mammals have four legs.
Dolphins do not have four legs.
THEREFORE dolphins probably aren’t mammals.

Most Congressmen live near Washington, DC.
Most US citizens don’t live near Washington, DC.
THEREFORE, there must be more Congressmen than citizens near Washington, DC.