Lsat: Logical Reasoning Flashcards
Premise Indicator Words
Because, since, for, for example, for the reason that, in that, given that, as indicated by, due to, owing to, this can be seen from, we know this by.
Conclusion Indicator Words
Thus, therefore, hence, consequently, as a result, so, accordingly, clearly, must be that, shows that, conclude that, follows that, for this reason.
One of their favorite forms places a conclusion indicator and premise indicator back to back such as
Therefore, since
Thus, because
Hence, due to
Additional Premise Indicator
Furthermore, moreover, besides, in addition, what’s more.
Counter Premise Indicators
But, yet, however, on the other hand, admittedly, in contrast, although, even though, still, whereas, in spite of, despite, after all.
Simple arguments include
Premise and Conclusion
Complex arguments include
Premise and conclusion/premise and conclusion.
Single speaker stimulus words to introduce alternate point of view.
Some people propose, many people believe, some argue that, some people argue that, some critics claim, some critics maintain, some scientists believe.
Quantity Indicator Words
All, every, most, some, several, few, sole, only, none, not all.
Probability Indicator words
Must, will, always, not always, probably, likely, should, would, not necessarily, could, rarely, never.
Must be true/Most supported definition
Must be true questions ask you to identify the answer choice that is best proven by the information in the stimulus.
“If the statements above are true, which one of the following must also be true?”
Must be true
“Which one of the following can be properly inferred from the passage?”
Must be true
Main point Definition
Main point questions ask you to find the primary conclusion made by the author.
“The main point of the argument is that”
Main point.
Point at issue
Point at issue questions require you to identify a point of contention between two speakers and thus these questions appear most exclusively with two speakers.
“Larew and Mendota disagree about whether.”
Point at issue.
Assumption question definition
Ask you to identify an assumption of the author’s argument.
“Which of the following is an assumption required by the argument above?”
Necessary Assumption
Justify the conclusion definition
Ask you to supply a piece of information that, when added to the premises, proves the conclusion.
Which one of the following, if assumed, allows the conclusion above to be properly be drawn?”
Justify the conclusion.
Strengthen/Support Definition
Ask you to select the answer choice that provides support for the author’s argument or strengthens it some way.
“Which one of the following, if true, most strengthens the argument?”
Strengthen/Support
“Which one of the following, if true, most strongly supports the statements above?”
Strengthen/support
Resolve the paradox definition
You must find the answer choice that best resolves the contradiction or discrepancy.
Weaken Definition
Weaken questions ask you to attack or undermine the author’s argument.
Which of the following, if true, most seriously weakens the argument?
Weaken
Method of reasoning definition
Ask you to describe, in abstract terms, the way in which the author made his or her argument.
“Which one of the following describes the technique of reasoning used above?”
Method of reasoning.
Flaw in the Reasoning
Ask you to describe, in abstract terms, the error of reasoning committed by authors.
“The reasoning in the astronomer’s argument is flawed because this argument.”
Flaw in the Reasoning
Parallel Reasoning
Ask you to identify the answer choice that contains reasoning that is most similar in structure to the reasoning presented in the stimulus.
“Which one of the following arguments is most similar in its pattern of reasoning to the argument above?”
Parallel Reasoning
Evaluate the Argument Definition
You must decide which answer choice will allow you to determine the logical validity of the argument.
“The answer to which one of the following questions would contribute most to an evaluation of the argument?”
Evaluate the argument
Cannot be true definition
Ask you to identify the answer choice that cannot be true or is most weakened based on the information in the stimulus.
“If the statements above are true, which one of the following cannot be true?”
Cannot be true.
Family #1
Must be true, main point, point at issue, method of reasoning, flaw in the reasoning, parallel reasoning.
Family #2
Assumption, justify the conclusion, strengthen/support, resolve the paradox.
Family #3
Weaken
Family #4
Cannot be true.
One of the signature features of the four question families is
That they define the parameters of what you can do with the information in each question.
First Family rule #1
- You must accept the stimulus information - even if it contains an error of reasoning-and use it to prove that one of the answer choices must be true.
First Family Rule #2
- Any information in answer choice that does not appear either directly in the stimulus or as combination of items in the stimulus will be incorrect.
Second Family Rule #1
The information in the stimulus is suspect. There are often reasoning errors present, and depending on the question you will help shore up the argument in some way.
Second Family #2
The answer choices are accepted as given, even if they influence “new” information. Your task is to determine which answer choice best meets the question posed in the stem.
Third Question Family rule #1
- The information in the stimulus is suspect. There are often reasoning errors present, and you will further weaken the argument in some way.
Third Question Family #2
- The answer choices are accepted as given, even if they include “new” information. Your task is to determine which answer choice best attacks the argument in the stimulus.
Fourth Family Rule. #1
You must accept the stimulus information- even if it contains an error of reasoning - and use it to prove that one of the answer choices cannot occur.
Fourth Family rule #2
Any information in answer choice that does not appear either directly in the stimulus or as a combination of items in the stimulus will be incorrect. The correct answer choice will directly disagree with the stimulus or a consequence of the stimulus.
The true effect of “except” is to
Logically negate the question stem.
Least has a similar effect to
Except when it appears in a question stem. Logically negates the question stem.
In must be true the correct answer can be proven by
Referring to the facts stated in the stimulus.
“If the statements above are true, which one of the following must also be true?”
Must be true
“If the information above is correct, which one of the following conclusions can be drawn properly drawn on the basis of it?”
Must be true
“The statements above, if true, most strongly support which one of the following?”
Must be true
“Which one of the following can be properly inferred from the passage?”
Must be true
“Which one of the following is most strongly supported by the information above?”
Must be true
You can often predict the occurrence of must be true questions because
The stimulus does not contain a conclusion.
“Many” can include
All
Most is not the same as
Many
Two answers that will always be correct in must be true questions.
- Paraphrased answers.
- Answers that are the sum of two or more stimulus statements. (Combination answers)
Must be True
Paraphrased answer choices.
Paraphrased answers are answers that rewrite a portion of the stimulus in different terms. When the answers mirror the stimulus, they are correct.
Most students have an unstated expectation of the conclusion appearing in the last sentence, and the test makers are able to prey upon this expectation by
(Main point questions)
Creating wrong answers that paraphrase the last sentence of the stimulus. To avoid this trap, simply avoid assuming the last sentence is the conclusion.
“Which one of the following most accurately expresses the main conclusion of the argument?”
Main point
“Which one of the following most accurately expresses the conclusion of the journalist’s argument?
Main point
“Which one of the following most accurately restates the main point of the passage?”
Main point
“The main point of the argument is that”
Main point
Main point
Correct answer choice
Answers that paraphrase the conclusion are correct in main point questions.
If an argument contains two conclusions you will be forced into identify,
Main point.
which one is the main conclusion and which one is the subsidiary conclusion.
In every case you should fill in the blank with the
(Fill in the blank)
Main point of the argument. In order to achieve this goal, you must read the stimulus for clues revealing the direction of the argument and the author’s intent.
Conditional reasoning
Is the broad name given to logical relationships composed of sufficient and necessary conditions. Any conditional statement consists of at least one sufficient condition and one necessary condition.
Sufficient Condition
Can be defined as an event or circumstance whose occurrence indicates that a necessary condition must also occur.
Necessary condition
Can be defined as an event or circumstance whose occurrence is required in order for a sufficient condition to occur.
If a sufficient condition occurs, you automatically know that
The necessary condition also occurs. If a necessary condition occurs, then it is possible but not certain that the sufficient condition will occur.
Three logical features of conditional reasoning
- The sufficient condition does not make the necessary condition occur.
- Temporally speaking, either condition can occur first, or two can occur at the same time.
- The conditional relationship stated does not have to reflect reality.
The sufficient condition does not make the the necessary condition occur. The sufficient condition does not
Actively cause the necessary condition to happen. In a conditional statement the occurrence of the sufficient condition is a sign or indicator that the necessary condition will occur, is occurring, or has already occurred.
Conditional reasoning occurs when a statement containing
Sufficient and necessary conditions is used to draw a conclusion based on the statement.
A+ ———> study
—————————————————
John received an A+ on the test, so he must have studied.
A+ ——-> study
(Repeat form)
A+ ————> study
—————————————————
John studied for the test, so he must have received an A+ on the test.
Study —————-> A + (invalid)
MISTAKEN REVERSAL
A+ ————-> study
—————————————————
John did not receive an A+ on the test, so he must not have studied.
~A+ ———> ~study (invalid)
MISTAKEN NEGATION
A+ ————-> study
—————————————————
John did not study for the test, so he must not have received an A+.
~study —————> ~A+
The repeat form simply
Restates the elements in the original order they appeared. This creates a valid inference.
A mistaken reversal switches the elements in the
Sufficient and necessary conditions, creating a statement that does not have to be true.
A mistaken negation negates both conditions, therefore creating a
Statement that does not have to be true.
A contrapositive denied the necessary condition, thereby making it
Impossible for the sufficient condition to occur.
Sufficient Condition Indicator
If, when, whenever, every, all, any, people who, in order to.
Necessary Condition Indicator
Then, only, only if, must, required, unless, except, until, without.
In the case of unless, except, until, and without, a special two step process called the unless equation is applied to the diagram.
- Whatever terms is modified by “unless”, “except”, “until”, or “without” becomes the necessary condition.
- The remaining term is negated and becomes the sufficient condition.
To diagram a statement that contains “unless”,
Convert the variable modified by “unless” into the necessary condition. Take the remainder, negate it, and convert it to the sufficient condition. The same technique applies to statements that contain “until”, “except”, and “without.”
“No” and “None” at the beginning modifies the
Necessary condition.
“When” introduces the
Sufficient condition.
When a stimulus contains conditional reasoning is combined with a must be true question stem
Immediately look for the repeat or contrapositive in the answer choices.
Statement 1: A —-> B
Statement 2: B —-> C
Chain: ?
Inference: ?
Chain: A ——> B ——>C
Inference: A ——> C
“Only” indicates a necessary condition when it is
Before a noun or phrase that must be true for another condition to hold.
As a modifier (not logical): “only” acts a modifier or adjective when it
Emphasizes or limits a noun without establishing a conditional relationship.
Ex: Mars has only small moons.”
When “only” modifies a noun without setting up a logical condition,
It is not functioning as necessary condition indicator.
F some A —-> LH <——-|—-> H
Every author works long hours, and if you work long hours you are never happy. Some authors are female.
Inferences: ?
Inferences: F some LH
F some ~H
A <———|——> H
The single arrow ——>
Introduced by sufficient and necessary words such as:
If, then, when, all, every, and only.
All X’s are Y’s
X ——> Y
~Y ——> ~X
The double arrow <———->
Introduced by
“If and only if” or by situations where the author implies that the arrow goes “both way”, such as by adding vice versa. After a conditional statement.
X if and only if Y
X <———-> Y
All W’s are Z’s, and all Z’s are W’s
W <—————> Z
Double arrow statements allow for only two possible outcomes:
The two variables occur together, or neither of the two variables occur.
The double- Not arrow <——|——>
Introduced by conditional statements where one of the terms is
Negative or by statements using words such as “no” and “none” that imply the two variables cannot “go together.”
No X’s are Y’s
X <————|——-—-> Y
If you are a T, then you are not a V,
T <———|———> V
T———> ~V
The word some can be defined as
At least one, possibly all.
Some are Not can be defined as
At least one is not, possibly all are not.
Some are not =
Not all
Some Indicators
Some, at least some, a few, a number, several, part of, a portion.
The word most can be defined as
Majority, possibly all. Most includes the possibility of all.
Most are not can be defined as
Majority are not, possibly all are not,
Most indicators
Most, majority, more than half, almost all, usually, typically.
All =
Most =
Some are not =
Most are not =
Some =
None =
Numerically
All = 100
Most = 51 to 100 (a majority)
Some are not = 0 to 99 (not all)
Most are not = 0 to 49
Some = 1 to 100 (“at least one”)
None = 0
Reversible statement are easily identifiable because
The relationship symbol is symmetrical and does not include an arrow pointing in one direction.
Non reversible terms have an arrow pointing
In just one direction.
Reversible relationships include
None <———-|———->
Some
Double arrow <———->
Non-reversible Relationship
All (——>)
Most |most. |
| ——->|
Additive inferences result from
Combining multiple statements through a common term and then deducing a relationship that does not include the common term.
Inherent inferences follow from
A single statement such as A——>B, and they are inferences that are known to be true simply from the relationship between the two variables.
When the arrow goes both ways,
You can infer most and some are inherent.
The negative logic ladder
None
|
V
Most are Not
|
V
Some are Not
The negative logic ladder
None
|
V
Most are Not
|
V
Some are Not
Variables that are linked in only one relationship are
Open
Variables that are linked in two or more relationships are
Closed.
Combine these terms
A some B
B——-> C
A some B ——> C
The vast majority of additive inferences require either
All or none statements in the chain.
Because all or none statements affect the entire group under discussion,
They are very restrictive and thus when other variables are joined to these relationships then inferences often result.
When looking to make inferences, do not start with
A variable involved in a double not arrow relationship and then try to go across the double not arrow.
The some train
To make an inference with a variable involved in a some relationship, an arrow
Leading away from the some relationship is required.
A some B —-> C
Inference:?
A some C
In the some train each variable is
Considered a station, and the relationships between each variable is a track.
A successful journey on the some train consists of at least
Two stops, and yields an inference. An unsuccessful journey means no inference is present.
The most train is similar to the some train, but because most is one step higher on the logic ladder,
The most train produces stronger inferences.
The critical difference between the some train and most train is that because most has direction
You can only follow the most arrow to make a most inference.
If you go backwards against the most arrow
It devolved the relationship to some, which is the inherent inference.
In general, two consecutive some’s, two consecutive most’s, or a some and most in succession will
Not yield any inferences.
For each argument, identify the conclusion and the premise(s). “Given that the price of steel is rising, we will no longer be able to offer discounts on our car parts.”
Features the premise indicator “given that.”
Premise: “Given that the price of steel is rising,”
Conclusion: “we will no longer be able to offer discounts on our car
parts.”
For each argument, identify the conclusion and the premise(s). “The political situation in Somalia is unstable owing to the ability of individual warlords to maintain powerful armed forces.”
Features the premise indicator “owing to.”
Premise: “owing to the ability of individual warlords to maintain
powerful armed forces.”
Conclusion: “The political situation in Somalia is unstable”
For each argument, identify the conclusion and the premise(s). “Since we need to have many different interests to sustain us, the scientists’ belief must be incorrect.”
Features the premise indicator “since.”
Premise: “Since we need to have many different interests to sustain
us,”
Conclusion: “the scientists’ belief must be incorrect.”
For each argument, identify the conclusion and the premise(s). “So, as indicated by the newly released data, we should push forward with our efforts to recolonize the forest with snowy tree crickets.”
Features the conclusion/premise form indicator “So, as indicated by.” Premise: “as indicated by the newly released data”
Conclusion: “we should push forward with our efforts to recolonize the
forest with snowy tree crickets.”
Either/Or definition
At least one of the two. Possibly both.
The way test makers indicate that the items in two conditions cannot both occur.
(Either/Or)
“But not both”
Either/Or are diagrammed by
Negate the sufficient condition.
Whenever you take the contrapositive of a statement with multiple terms in the sufficient or necessary condition,
“And”, turns into “or”, and “or” turns into “and”
“Or” contrapositive is
“And”
“And” contrapositive is
“Or”
The double arrow indicates that
Two terms must always occur together.
Biconditionals indicate each term is
Both sufficient and necessary for the other.
Terms in double arrow relationships either occur
Together or both do not occur.
The double arrow is typically introduced in any of the following three ways:
- Use of phrase “If and only if”
- Use of the phrase “Vice Versa”
- By repeating and reversing the terms.
The double not arrow is similar to the
“Not equal” sign of logic, the two terms at the end of the sign cannot be selected at the same time.
Weaken questions require
you to select the answer choice that undermines the author’s argument as decisively as possible.
The stimulus will contain an argument. Because you are asked to weaken the author’s reasoning, and reasoning requires a conclusion, an argument will always be present. In order to maximize your chances of success you must
identify, isolate, and assess the premises and the conclusion of the argument. Only by understanding the structure of the argument can you gain the perspective necessary to attack the author’s position.
Almost all correct Weaken answer choices impact the
conclusion. The more you know about the specifics of the conclusion, the better armed you will be to differentiate between correct and incorrect answers.
Weaken questions often yield strong
prephrases. Be sure to actively consider the range of possible answers before proceeding to the answer choices.
The stem uses the word “weaken” or a synonym. Following are some examples of words or phrases used to indicate that your task is to weaken the argument:
weaken, attack, refute, undermine, argue against, call into question, cast doubt, challenge, damage, counter.
“Which one of the following, if true, most seriously weakens the argument?”
Weaken
“Which one of the following, if shown to be a realistic possibility, would undermine the argument?”
Weaken
“Which one of the following, if true, most undermines the researcher’s argument?”
Weaken
“Which one of the following, if true, would most call into question the analysts’ explanation of the price increase?”
Weaken
“Which one of the following, if true, could be used by Cora to counter Bernard’s rejection of her explanation?”
Weaken
“Which one of the following, if true, is the strongest logical counter parent P can make to parent Q’s objection?”
Weaken
“Which one of the following, if true, most calls into question the claim above?”
Weaken
In practice, almost all correct LSAT Weaken question answers leave the
premises untouched.
The key to weakening an LSAT argument is to
attack the conclusion.
In weaken questions the conclusion is the part of the argument that is most likely to be attacked, but the correct answer choice will not simply contradict the conclusion. Instead, the correct answer will
undermine the conclusion by showing that the conclusion fails to account for some element or possibility. In this sense, the correct answer often shows that the conclusion does not necessarily follow from the premises even if the premises are true.
Answers that weaken the argument’s conclusion will attack
assumptions made by the author.
Common Weakening Scenarios
- Incomplete Information. The author fails to consider all of the possibilities, or relies upon evidence that is incomplete. This flaw can be attacked by bringing up new possibilities or information.
- Improper Comparison. The author attempts to compare two or more items that are essentially different.
- Qualified Conclusion. The author qualifies or limits the conclusion in such a way as to leave the argument open to attack.
The stimuli for weaken questions contain errors of
assumption.
To weaken a conditional conclusion, attack the
necessary condition by showing that the necessary condition does not need to occur in order for the sufficient condition to occur.
To weaken a conditional conclusion, attack the necessary condition by showing that the necessary condition does not need to occur in order for the sufficient condition to occur.
This can be achieved by presenting a counterexample or by presenting information that shows that the sufficient condition can occur without the necessary condition.
When you have conditional reasoning in the stimulus and a Weaken question, immediately look for
an answer that attacks the necessary condition.
Keep these fundamental rules in mind when you approach Weaken questions:
- The stimulus will contain an argument.
- Focus on the conclusion.
- The information in the stimulus is suspect. There are often reasoning errors present, and you must read the argument very carefully.
- Weaken questions often yield strong prephrases.
- The answer choices are accepted as given, even if they include “new” information.
Several scenarios that can occur in LSAT Weaken question stimuli are easy to
recognize and attack
- Incomplete information
- Improper comparison
- Qualified Conclusion
There are certain incorrect answer choices that appear frequently in weaken questions:
- opposite answers
- shell game answers
- out of scope
MOST causal conclusions are flawed because
there can be alternate explanations for the stated relationship: another cause could account for the effect; a third event could have caused both the stated cause and effect; the situation may in fact be reversed; the events may be related but not causally; or the entire occurrence could be the result of chance.
causality occurs when
one event is said to make another occur. The cause is the event that makes the other occur; the effect is the event that follows from the cause.
the cause must occur
before the effect, and the cause is the “activator” or “ignitor” in the relationship. The effect always happens at some point in time after the cause.
A cause-and-effect relationship has a signature characteristic
the cause makes the effect happen.
The following terms often introduce a cause and effect relationship:
Caused by, because of, responsible for, reason for, leads to, induced by, promoted by, determined by, produced by, product of, played a role in, was a factor in, is an effect of.
The Difference Between Causality and Conditionality
- The chronology of the two events can differ.
- The connection between the events is different.
- The language used to introduce the statements is different.
In cause and effect statements there is an implied temporal relationship: the cause must
happen first and the effect must happen at some point in time after the cause.
In sufficient and necessary statements there is no implied temporal relationship: the sufficient condition can
happen before, at the same time, or after the necessary condition.
In cause and effect statements the events are
related in a direct way.
In conditional statements the sufficient and necessary conditions are often related directly, but
they do not have to be.
Causal indicators are active, almost powerful words, whereas
most conditional indicators do not possess those traits.
Causal statements can be found in the
premise or conclusion of an argument.
If the causal statement is the conclusion, then
the reasoning is flawed.
If the causal statement is the premise, then the argument
may be flawed, but not because of the causal statement.
one of the critical issues in determining whether flawed causal reasoning is present is
identifying where in the argument the causal assertion is made.
The classic mistaken cause and effect reasoning is when
a causal assertion is made in the conclusion, or the conclusion presumes a causal relationship.
If a causal claim is made in the premises, however, then
no causal reasoning error exists in the argument.
There are two scenarios that tend to lead to causal conclusions in Logical Reasoning questions:
- One event occurs before another
- Two (or more) events occur at the same time
When one event occurs before another event, many people fall into the trap of assuming that
the first event caused the second event. This does not have to be the case.
When two events occur simultaneously, many people assume that
one event caused the other. While one event could have caused the other, the two events could be the result of a third event, or the two events could simply be correlated but one does not cause the other.
Understanding the assumption that is at the heart of a causal conclusion is essential to
knowing why certain answers will be correct or incorrect.
When an LSAT speaker concludes that one occurrence caused another, that speaker also assumes that
the stated cause is the only possible cause of the effect and that consequently the stated cause will always produce the effect. This assumption is incredibly extreme and far- reaching, and often leads to surprising answer choices that would appear incorrect unless you understand this assumption.
The conclusion is flawed because it is not necessary that the one element caused the other to occur:
the two could simply be correlated in some way or the connection could be random.
Thus, in every argument with a causal conclusion that appears on the LSAT, the speaker believes that
the stated cause is in fact the only cause and all other theoretically possible causes are not, in fact, actual causes.
Whenever you identify a causal relationship in the conclusion of an LSAT problem, immediately prepare to
either weaken or strengthen the argument.
Attacking a cause and effect relationship in Weaken questions almost always consists of performing one of the following tasks:
A. Find an alternate cause for the stated effect
B. Show that even when the cause occurs, the effect does not occur.
C. Show that although the effect occurs, the cause did not occur.
D. Show that the stated relationship is reversed
E. Show that a statistical problem exists with the data used to make the causal statement.
If the data used to make a causal statement is in error, then
the validity of the causal claim is in question.
Causality occurs when
one event is said to make another occur.
The cause is the event that
makes the other occur.
the effect is the event that
follows from the cause.
Keep these fundamental rules in mind when approaching Strengthen, Justify the Conclusion, and Assumption questions:
- The stimulus will contain an argument. Because you are being asked about the author’s reasoning, and reasoning requires a conclusion, an argument will always be present.
- Focus on the conclusion. Almost all correct answer choices impact the conclusion.
- The information in the stimulus is suspect. There are often reasoning errors present, and you must read the argument very carefully in order to know how to shore up the argument.
- These questions often yield strong prephrases. Make sure you actively consider the range of possible answers before proceeding to the answer choices.
- The answer choices are accepted as given, even if they include “new” information. Like Weaken questions, the answer choices to the problems in this chapter can bring into consideration information outside of or tangential to the stimulus.
The Difference Between Strengthen, Justify the Conclusion, and Assumption Questions
Strengthen questions ask you to support the argument in any way possible. This type of answer has great range, as the additional support provided by the answer choice could be relatively minor or major.
Justify the Conclusion questions ask you to strengthen the argument so powerfully that the conclusion is made logical. Compared to a Strengthen question, the answer to a Justify question must strengthen the conclusion so it is 100% proven; anything less and the answer choice is incorrect.
Assumption questions ask you to identify a statement that the argument assumes or supposes.
Speaking in numerical terms, any answer choice that strengthens the argument, whether by
1% or by 100%, is correct.
The correct answer to a Justify the Conclusion question is
sufficient to prove the conclusion when added to the premises.
Assumption questions ask you to identify a statement that
the argument assumes or supposes. An assumption is simply an unstated premise— what must be true in order for the argument to be true.
Strengthen questions ask you to identify the answer choice that
Best supports the argument. The correct answer choice simply helps the argument in some way.
Following are some examples of words or phrases used to indicate that your task is to strengthen the argument:
strengthen, support, helps, and
most justifies.
Following are several Strengthen question stem examples from actual LSATs:
“Which one of the following, if true, most strengthens the argument?”
“Which one of the following, if true, most strongly supports the statement above?”
“Which one of the following, if true, does most to justify the conclusion above?”
“Each of the following, if true, supports the claim above EXCEPT:”
How to Strengthen an Argument
- Identify the conclusion—this is what you are trying to strengthen!
- Personalize the argument.
- Look for weaknesses in the argument.
- Arguments that contain analogies or use surveys rely upon the validity of those analogies and surveys. Answer choices that strengthen the analogy or survey, or establish their soundness, are usually correct.
- Remember that the correct answer can strengthen the argument just a little or a lot. This variation is what makes these questions difficult.
Strengthen Incorrect Answer Traps
- Opposite Answers. These answers do the exact opposite of what is needed—they weaken the argument.
- In Strengthen questions, the Shell Game is usually used to support a conclusion that is similar to, but slightly different from, the one presented in the stimulus.
- Out of Scope Answers. These answers simply miss the point of the argument and support issues that are either unrelated to the argument or tangential to the argument.
Because Strengthen and Weaken questions require you to perform opposite tasks, to strengthen a causal conclusion you
take the exact opposite approach that you would in a Weaken question.
In Strengthen questions, supporting a cause and effect relationship almost always consists of performing one of the following tasks:
A. Eliminate any alternate causes for the stated effect.
B. Show that when the cause occurs, the effect occurs.
C. Show that when the cause does not occur, the effect does not occur.
D. Eliminate the possibility that the stated relationships
Remember, to
strengthen a
causal argument
you must perform
tasks that
are
opposite of those
that weaken a
causal argument.
Because the author believes there is only one cause (the stated cause in
the argument), (strengthen)
eliminating other possible causes strengthens the
conclusion.
Because the author believes that the cause always produces the effect
Because the author believes that the cause always produces the effect
Because the author believes that the cause and effect relationship is
correctly stated, eliminating the possibility that the
relationship is
backwards (the claimed effect is actually the cause of the claimed cause)
strengthens the conclusion
If the data used to make a causal statement is in error, then the validity of
the causal claim is in question. Any information that eliminates error or
reduces the possibility of error will
support the argument.
Strengthen questions ask you to identify
the answer choice that best supports
the argument.
Use the following points to effectively strengthen arguments:
- Identify the conclusion—this is what you are trying to strengthen!
- Personalize the argument.
- Look for weaknesses or holes in the argument.
The same type of wrong answer traps appear in Strengthen as in Weaken
questions
- Opposite Answers.
- Shell Game Answers.
- Out of Scope Answers.
In Strengthen questions, supporting a cause and effect relationship almost
always consists of performing one of the following tasks:
A. Eliminate any alternate causes for the stated effect
B. Show that when the cause occurs, the effect occurs
C. Show that when the cause does not occur, the effect does not occur
D. Eliminate the possibility that the stated relationship is reversed
E. Show that the data used to make the causal statement is accurate, or
eliminate possible problems with the data
Justify the Conclusion questions require you to select an answer choice that
logically proves the conclusion of the argument.
Justify questions are perfect
strengthening questions: the correct answer will strengthen the argument so well
that the conclusion must follow from the combination of the premises and the
correct answer choice.
Apply the Justify FormulaTM
Premises + Answer choice = Conclusion
“The conclusion above follows logically if which one of the following
is assumed?”
Justify
“The conclusion above follows logically if which one of the following
is assumed?”
Justify
“Which one of the following, if assumed, would allow the conclusion to
be properly drawn?”
Justify
“Which one of the following, if true, enables the conclusion to be
properly drawn?”
Justify
“Which one of the following, if assumed, enables the argument’s
conclusion to be properly inferred?”
Justify
“Which one of the following is an assumption that would serve to justify
the conclusion above?”
Justify
“The environmentalist’s conclusion would be properly drawn if it were
true that the”
Justify
“The conclusion above is properly drawn if which one of the following
is assumed?”
Justify
most Justify stimuli either use
Conditional Reasoning or contain numbers
and percentages. Because both forms of reasoning allow for certainty
when drawing a conclusion.
Stimuli that
contain numbers
or percentages in
the stimulus also
allow for
the
exactitude justify
questions require.
Strengthen
questions with
the phrase “most
justifies” in the
question stem
can largely be
treated like
Justify questions,
but you must
understand there
is a window that
allows for an
answer that does
not perfectly
justify the
conclusion.
Because Justify the Conclusion questions can be
characterized in formulaic terms, you can often solve these questions using a
mechanistic approach. This approach requires
- Any “new” element in the conclusion will appear in the correct answer.
- Elements that are common to the conclusion and at least one premise
normally do not appear in the correct answer. - Elements that appear in the premises but not the conclusion usually
appear in the correct answer.
Justify Mechanical Approach 1. Any “new” element in the conclusion will appear in the correct answer.
“New” or “rogue” elements are those that did not appear in any of the
premises. By definition, any new element in the conclusion must be
proven to occur, and so if the new element is not in the premises then it
must be introduced in the correct answer choice.
Justify Mechanical Approach 2. Elements that are common to the conclusion and at least one premise
normally do not appear in the correct answer
If an element occurs in both the conclusion and premises, then there is a
bridge already established that justifies the presence of the element in the
conclusion. Hence, the correct answer need not contain this element.
Justify Mechanical Approach 3. Elements that appear in the premises but not the conclusion usually
appear in the correct answer.
Although these premise elements do not have to appear in the correct
answer, they often do because they represent a convenient linking point.
Justify mechanical rules condense to the following:
link new elements in the
premises and conclusion and ignore elements common to both.
Most Justify the Conclusion question stems typically contain some of the
following three features:
- The stem uses the word “if” or another sufficient condition indicator.
- The stem uses the phrase “allows the conclusion to be properly
drawn” or “enables the conclusion to be properly drawn.” - The stem does not lessen the degree of justification.
The correct
answer to an
Assumption
question is
a statement the
author must
believe in order for
the conclusion to
make sense.
“Which one of the following is an assumption required by the argument
above?”
Assumption
“Which one of the following is an assumption upon which the argument
depends?”
Assumption
“The argument assumes which one of the following?
Assumption
“The conclusion in the passage above relies on which one of the
following assumptions?”
Assumption
“The position taken above presupposes which one of the following?”
Assumption
“The conclusion cited does not follow unless”
Assumption
An assumption is described solely as a linking statement, one that
links two premises or links a premise to the conclusion.
On the LSAT, assumptions play one of two roles
the Supporter or the
Defender
The Supporter role is the traditional linking role, where
an
assumption connects the pieces of the argument.
Because Supporters often connect “new” or “rogue” pieces of information in
the argument, the Supporter role generally
appears similar to the Justify the
Conclusion answers.
Justify the Conclusion answers are assumptions of the argument,
especially when
the argument contains a conditional structure.
The Supporter
assumption, by definition,
closes the hole by linking the elements together.
Defender assumptions
protect the
argument by eliminating ideas that could weaken the argument.
In order to
believe the argument is “well-considered and airtight,” an author must
assume
that every possible objection has been considered and rejected.
Defender Assumption:
These assumptions contain statements that
eliminate ideas or assertions that would
undermine the conclusion. In this sense, they
“defend” the argument by showing that a
possible source of attack has been eliminated.
Supporter Assumption
These assumptions link together new or rogue
elements in the stimulus or fill logical gaps in the
argument.
The Assumption Negation TechniqueTM
Only a few types of LSAT questions allow you to double-check your answer.
Assumption questions are one of those types, and you should use the
Assumption Negation Technique to decide between Contenders or to confirm
that the answer you have chosen is correct.
- Logically negate the answer choices under consideration.
- The negated answer choice that attacks the argument will be the correct
answer. When the correct answer choice is negated, the answer must weaken the
argument
To logically
negate a
conditional
statement,
negate
the
necessary
condition.
Three Quirks of Assumption Question Answer Choices
- Watch for answers starting with the phrase “at least one” or “at least
some.” - Avoid answers that claim an idea was the most important consideration
for the author. - Watch for the use of “not” or negatives in assumption answer choices.
The correct answer to an
Assumption question will normally fit one of the following categories:
A. Eliminates any alternate cause for the stated effect
B. Shows that when the cause occurs, the effect occurs
C. Shows that when the cause does not occur, the effect does not occur
D. Eliminates the possibility that the stated relationship is reversed
E. Shows that the data used to make the causal statement are accurate, or
eliminates possible problems with the data
An assumption is simply an
an unstated premise of the argument; that is, an
integral component of the argument that the author takes for granted and leaves
unsaid
Resolve the Paradox questions are generally easy to spot because of their
distinctive stimuli:
each stimulus presents a situation where two ideas or
occurrences contradict each other.
Besides the discrepant or contradictory facts, most Resolve the Paradox stimuli
contain the following features:
- No conclusion
- Language of contradiction
In order to present a paradox, the test makers use language that signals a
contradiction is present, such as:
But, However, Yet, Although, Paradoxically,
Surprisingly
Key words that indicate your task is to resolve a problem
Action: Resolve, explain, reconcile.
Problem: Paradox, Discrepancy, contradiction, conflict, puzzle.
“Which one of the following, if true, would most effectively resolve the
apparent paradox above?”
Paradox
“Which one of the following, if true, most helps to resolve the apparent
discrepancy in the passage above?”
Paradox
“Which one of the following, if true, most helps to explain the puzzling
fact cited above?”
Paradox
“Which one of the following, if true, most helps to reconcile the
discrepancy indicated above?”
Paradox
“Which one of the following, if true, most helps to resolve the apparent
conflict described above?”
Paradox
The correct
answer will
positively resolve
the paradox so
that
both sides
are true and the
conditions in the
stimulus have
been met.
If an answer
supports or
proves only one
side of the
paradox, that
answer will be
incorrect. The
correct answer
must show how
both sides
coexist.
The
correct answer will actively resolve the paradox, that is, it will
allow both sides
to be factually correct and it will either explain how the situation came into
being or add a piece of information that shows how the two ideas or
occurrences can coexist.
Because you are not seeking to disprove one side of the situation in a paradox, you must
select the answer choice that
contains a possible cause of the situation.
if the
stimulus contains
a paradox where
two items are
different, then
an
answer choice
that explains why
the two are
similar cannot be
correct.
If the stimulus
contains a
paradox where
two items are
similar, then
an
answer choice
that explains a
difference
between the two
cannot be
correct.
A similarity cannot
explain a
difference, and a
difference cannot
explain a
similarity.
When attempting to resolve the paradox in the stimulus, you must address
the
facts of the situation.
In paradox many incorrect answers will try to lure you with
reasonable solutions that do not quite meet the stated facts. These answers are incorrect. The correct answer must conform to the specifics of the stimulus.
Each Resolve the Paradox stimulus presents a situation where
two ideas or
occurrences contradict each other.
Besides the discrepant or contradictory facts, most Resolve the Paradox stimuli
contain the following features:
- No conclusion
- Language of contradiction
In paradox the following types of
answers are incorrect:
- Explains only one side of the paradox
- Similarities and differences
Method of Reasoning questions require you to
select the answer choice that best
describes the method used by the author to make the argument.
Method of Reasoning questions
feature the following information structure, modified slightly for the abstract
nature of these questions:
- You can use only the information in the stimulus to prove the correct
answer choice. - Any answer choice that describes an element or a situation that does not
occur in the stimulus is incorrect.
As you attack
each question,
keep in mind that
Method of
Reasoning
questions are
simply
abstract
Must Be True
questions. Use
the information in
the stimulus to
prove or disprove
each answer
choice
Which one of the following most accurately
describes the relationship between Jane’s argument
and Mark’s argument?
Method of Reasoning
“The claim that inventors sometimes serve as their own engineers plays
which one of the following roles in the argument?”
Method of Reasoning
“The statement ‘thinking machines closely modeled on the brain are also
likely to fail’ serves which one of the following roles in Yang’s
argument?”
Method of Reasoning
“The assertion that a later artist tampered with Veronese’s painting
serves which one of the following functions in the curator’s argument?”
Method of Reasoning
The claim that people have positive or negative
responses to many nonsense words plays which one
of the following roles in the argument?
Method of Reasoning
Ruth responds to Jorge’s criticism by
Method of Reasoning
Which one of the following most accurately
describes the role played in the psychologist’s
argument by the claim that the obligation to express
gratitude cannot be fulfilled anonymously?
Method of Reasoning
Sue challenges Anne’s reasoning by
Method of Reasoning
Which one of the following most accurately
describes the role played in the argument by the
statement that zooplankton feed upon
phytoplankton?
Method of Reasoning
The claim that humans are still biologically adapted
to a diet of wild foods plays which one of the
following roles in the nutritionist’s argument?
Method of Reasoning
Jerome responds to Ingrid’s claim by
Method of Reasoning
The phrase “certain traits like herding ability risk
being lost among pedigreed dogs” serves which one
of the following functions in the argument?
Method of Reasoning
Method of Reasoning question stems use a variety of formats, but in each case
the stem refers to the method, technique, strategy, or process used by the author
while making the argument. Here are several question stem examples:
“The method of the argument is to”
“The argument proceeds by”
“The argument derives its conclusion by”
“Which one of the following describes the technique of reasoning used
above?”
“Which one of the following is an argumentative strategy employed in
the argument?”
“The argument employs which one of the following reasoning
techniques?”
“Aiesha responds to Adam’s argument by”
The Fact Test in Method of Reasoning Questions
If an answer choice describes an event that did not occur in the stimulus,
then that answer is incorrect.
The stimulus for a Method Reasoning question will contain
an argument, and
the argument can contain either valid or invalid reasoning.
Incorrect Answers in Method of Reasoning Questions
- “New” Element Answers
- Half Right, Half Wrong Answer
- Exaggerated Answers
- The Opposite Answer
- The Reverse Answer
“The claim that inventors sometimes serve as their own engineers plays
which one of the following roles in the argument?”
Method of Reasoning-Argument Part
“The statement ‘thinking machines closely modeled on the brain are also
likely to fail’ serves which one of the following roles in Yang’s
argument?”
Method of Reasoning-Argument Part
“The assertion that a later artist tampered with Veronese’s painting
serves which one of the following functions in the curator’s argument?”
Method of Reasoning-Argument Part
The stimuli that accompany Method-AP questions tend to be more complex
than the average LSAT stimulus. Some problems feature
two conclusions (one
is the main conclusion, the other is a subsidiary conclusion), and often the
stimulus includes two different viewpoints or the use of counterpremises.
One trick used by the test makers in Method-AP questions is to create wrong
answers that
describe parts of the argument other than the part named in the
question stem. These answers are particularly attractive because they do
describe a part of the argument, just not the part referenced in the question stem.
Argument Part (AP) questions are a specific subset of Method of Reasoning
questions. In Method-AP questions, the question stem
cites a specific portion of
the stimulus and then asks you to identify the role that the cited portion plays in
the structure of the argument.
Flaw in the Reasoning questions are exactly the same as Method of Reasoning
questions with the important exception
that the question stem indicates that the
reasoning in the stimulus is flawed.
“Which one of the following most accurately describes a flaw in the
argument’s reasoning?”
Flaw
“The reasoning in the argument is most vulnerable to criticism on the
ground that the argument”
Flaw
“The reasoning above is flawed because it fails to recognize that”
Flaw
“A questionable aspect of the reasoning above is that it”
Flaw
“The reasoning in the argument is fallacious because the argument”
Flaw
Which one of the following is a questionable
argumentative strategy employed in the editorial’s
argument?
Flaw
The argument is most vulnerable to criticism on
which one of the following grounds?
Flaw
The reasoning in the activist’s argument is flawed
because that argument
Flaw
The reasoning in the philosopher’s argument is
flawed because the argument
Flaw
The reasoning in the argument is flawed in that the
argument
Flaw
The reasoning in the argument is flawed in that the
argument
Flaw
The reasoning in the astronomer’s argument is flawed
because this argument
Flaw
The reasoning in the argument is most vulnerable to
criticism on the grounds that the argument
Flaw
In flaw the correct answer will identify
the error in the author’s reasoning and
then describe that error in general terms. Beware of answers that describe a
portion of the stimulus but fail to identify the error in the reasoning.
Flaw : Uncertain Use of a Term or Concept
As an argument progresses, the author must use each term in a constant,
coherent fashion. Using a term in different ways is inherently confusing and
undermines the integrity of the argument
In Flaw “depending on the ambiguous use of a key term”
Uncertain Use of a Term or Concept
In Flaw “it confuses two different meanings of the word ‘solve’ ”
Uncertain Use of a Term or Concept
In Flaw “relies on interpreting a key term in two different ways”
Uncertain Use of a Term or Concept
In Flaw “equivocates with respect to a central concept”
Uncertain Use of a Term or Concept
In Flaw “allows a key term to shift in meaning from one use to the next”
Uncertain Use of a Term or Concept
In Flaw “fails to define the term”
Uncertain Use of a Term or Concept
ad hominem/A source argument can take different forms including
- Focusing on the motives of the source.
- Focusing on the actions of the source (as in the above example).
ad hominem/Source Argument
this type of flawed argument attacks the person
(or source) instead of the argument they advance. Because the LSAT is
concerned solely with argument forms, a speaker can never validly attack the
character or motives of a person; instead, a speaker must always attack the
argument advanced by a person.
“makes an attack on the character of opponents”
ad hominem/source argument
“it is directed against the proponent of a claim rather than against the
claim itself”
ad hominem/source argument
“he directs his criticism against the person making the argument rather
than directing it against the argument itself”
ad hominem/source argument
“it draws conclusions about the merit of a position and about the content
of that position from evidence about the position’s source”
ad hominem/source argument
“assuming that a claim is false on the grounds that the person defending
it is of questionable character”
ad hominem/source argument
Circular Reasoning
In circular reasoning the author assumes as true what is supposed to be proved.
“it assumes what it seeks to establish”
Circular Reasoning
“argues circularly by assuming the conclusion is true in stating the
premises”
Circular Reasoning
“presupposes the truth of what it sets out to prove”
Circular Reasoning
“the argument assumes what it is attempting to demonstrate”
Circular Reasoning
“it takes for granted the very claim that it sets out to establish”
Circular Reasoning
“it offers, in place of support for its conclusion, a mere restatement of
that conclusion”
Circular Reasoning
Errors of Conditional Reasoning
When describing a Mistaken Negation or a Mistaken Reversal, the test makers
must focus on the error common to both: confusing the sufficient condition with
the necessary condition.
Remember, a
Mistaken
Negation and a
Mistaken
Reversal are
contrapositives of
each other, so the
error behind both
is identical.
In flaw: Confuses a necessary condition for a sufficient condition/ Confuses a sufficient condition for a necessary condition
Errors of Conditional Reasoning
if you identify a stimulus with conditional reasoning and are
asked a Flaw question, you can
quickly scan the answers for the one answer
that contains “sufficient,” “necessary,” or both.
In flaw : Mistaken Cause and Effect
- Assuming a causal relationship on the basis of the sequence of events.
- Assuming a causal relationship when only a correlation exists.
- Failure to consider an alternate cause for the effect, or an alternate cause
for both the cause and the effect. - Failure to consider that the events may be reversed.
In flaw: “mistakes the observation that one thing happens after another for proof
that the second thing is the result of the first”
“mistakes the observation that one thing happens after another for proof
that the second thing is the result of the first”
In flaw: “mistakes a temporal relationship for a causal relationship”
“mistakes a temporal relationship for a causal relationship”
In flaw: “assumes a causal relationship where only a correlation has been
indicated”
“assumes a causal relationship where only a correlation has been
indicated”
In flaw: “confusing the coincidence of two events with a causal relation between
the two”
“confusing the coincidence of two events with a causal relation between
the two”
In flaw: “fails to exclude an alternative explanation for the observed effect”
“fails to exclude an alternative explanation for the observed effect”
In flaw: “overlooks the possibility that the same thing may causally contribute
both to education and to good health”
“overlooks the possibility that the same thing may causally contribute
both to education and to good health”
In flaw: “the author mistakes an effect for a cause”
“the author mistakes an effect for a cause”
Straw Man
This error occurs when an author attempts to attack an opponent’s position by
ignoring the actual statements made by the opposing speaker and instead
distorts and refashions the argument, making it weaker in the process.
Often this error is accompanied by the phrase “what you’re saying is” or “if I
understand you correctly,”
Straw man
“refutes a distorted version of an opposing position”
Straw man
“misdescribing the student representative’s position, thereby making it
easier to challenge”
Straw man
“portrays opponents’ views as more extreme than they really are”
Straw man
“distorts the proposal advocated by opponents”
Straw man
General Lack of Relevant Evidence for the Conclusion
Some LSAT authors misuse information to such a degree that they fail to
provide any information to support their conclusion or they provide information
that is irrelevant to their conclusion.
Note the use of
the construction
“some critics
claim…” As usual,
the author’s main
point is that
the
claim that the
critics are making
is wrong
“The author cites irrelevant data.”
General Lack of Relevant Evidence for the Conclusion
“draws a conclusion that is broader in scope than is warranted by the
evidence advanced”
General Lack of Relevant Evidence for the Conclusion
“It uses irrelevant facts to justify a claim about the quality of the
disputed product.”
General Lack of Relevant Evidence for the Conclusion
“It fails to give any reason for the judgment it reaches.”
General Lack of Relevant Evidence for the Conclusion
“It introduces information unrelated to its conclusion as evidence in
support of that conclusion.”
General Lack of Relevant Evidence for the Conclusion
Internal Contradiction
an internal contradiction
(also known as a self-contradiction) occurs when an author makes conflicting
statements
“bases a conclusion on claims that are inconsistent with each other”
Internal Contradiction
“the author makes incompatible assumptions”
Internal Contradiction
“introduce information that actually contradicts the conclusion”
Internal Contradiction
“offers in support of its conclusion pieces of evidence that are mutually
contradictory”
Internal Contradiction
“some of the evidence presented in support of the conclusion is
inconsistent with other evidence provided”
Internal Contradiction
“assumes something that it later denies, resulting in a contradiction”
Internal Contradiction
“the judgement of experts is applied to a matter in which their
expertise is irrelevant”
Appeal to Authority
Appeal Fallacies
- Appeal to Authority
- Appeal to Popular Opinion/Appeal to Numbers
- Appeal to Emotion
- Appeal to Authority
An Appeal to Authority uses the opinion of an authority in an attempt to
persuade the reader. The flaw in this form of reasoning is that the authority may not have relevant knowledge or all the information
regarding a situation, or there may a difference of opinion among
experts as to what is true in the case.
“the argument inappropriately appeals to the authority of the
mayor”
Appeal to Authority
“it relies on the judgment of experts in a matter to which their
expertise is irrelevant”
Appeal to Authority
“it treats popular opinion as if it constituted conclusive evidence
for a claim”
Appeal to Popular Opinion/Appeal to Numbers
“accepts a claim on mere authority, without requiring sufficient
justification”
Appeal to Authority
Appeal to Popular Opinion/Appeal to Numbers
This error states that a position is true because the majority believes it to
be true.
“attempts to discredit legislation by appealing to public
sentiment”
Appeal to Popular Opinion/Appeal to Numbers
“a claim is inferred to be false merely because a majority of people believe it to be false”
Appeal to Popular Opinion/Appeal to Numbers
“the argument, instead of providing adequate reasons in support
of its conclusion, makes an appeal to popular opinion”
Appeal to Popular Opinion/Appeal to Numbers
Appeal to Emotion
An Appeal to Emotion occurs when emotions or emotionally-charged
language is used in an attempt to persuade the reader.
“attempts to persuade by making an emotional appeal”
Appeal to Emotion
“uses emotive language in labeling the proposals”
Appeal to Emotion
“the argument appeals to emotion rather than reason”
Appeal to Emotion
Survey Errors
-The survey uses a biased sample
-The survey questions are improperly constructed.
-Respondents to the survey give inaccurate responses.
“uses evidence drawn from a small sample that may well be
unrepresentative”
Survey Errors
“generalizes from an unrepresentative sample”
Survey Errors
“states a generalization based on a selection that is not representative of
the group about which the generalization is supposed to hold true”
Survey Errors
“supports a universal claim on the basis of a single example”
Exceptional Case/Overgeneralization
Exceptional Case/Overgeneralization
This error takes a small number of instances and treats those instances as if they
support a broad, sweeping conclusion.
“The argument generalizes from too small a sample of cases
Exceptional Case/Overgeneralization
“Too general a conclusion is made about investing on the basis of a
single experiment”
Exceptional Case/Overgeneralization
“bases a general claim on a few exceptional instances”
Exceptional Case/Overgeneralization
Composition and division errors involve
Judgments made about groups and
parts of a group.
Errors of Composition and Division
An error of composition occurs when the author attributes a characteristic of
part of the group to the group as a whole or to each member of the group.
“assuming that because something is true of each of the parts of a whole
it is true of the whole itself”
Errors of Composition and Division
“treats as similar two cases that are different in a critical respect”
False Analogy
“takes the view of one lawyer to represent the views of all lawyers”
Errors of Composition and Division
“improperly infers that each and every scientist has a certain
characteristic from the premise that most scientists have that
characteristic”
Errors of Composition and Division
An error of division occurs when
the author attributes a characteristic of the
whole (or each member of the whole) to a part of the group
False Analogy
occurs when the
author uses an analogy that too dissimilar to the original situation to be
applicable.
“treats two kinds of things that differ in important respects as if they do
not differ”
False Analogy
False Dilemma
assumes that only two courses of action are available when
there may be others.
Errors in the Use of Evidence
Mis-assessing the force of evidence is a frequent error committed by LSAT
authors.
“treats failure to prove a claim as constituting denial of that
claim”
Lack of evidence for a position is taken to prove that position is false
“taking a lack of evidence for a claim as evidence undermining
that claim”
Lack of evidence for a position is taken to prove that position is false
“There has been no evidence given against the existence of God,
so God must exist.”
Lack of evidence against a position is taken to prove that position is
true.
“it confuses undermining an argument in support of a given
conclusion with showing that the conclusion itself is false”
Some evidence against a position is taken to prove that position is false.
“treating the failure to establish that a certain claim is false as equivalent to a demonstration that the claim is true”
Lack of evidence against a position is taken to prove that position is
true.
“the argument takes evidence showing merely that its conclusion
could be true to constitute evidence showing that the conclusion
is in fact true”
Some evidence for a position is taken to prove that position is true
“treats a claim about what is currently the case as if it were a claim about
what has been the case for an extended period”
Time Shift Errors
Time Shift Errors
the mistake involves assuming
that conditions will remain constant over time, and that what was the case in the
past will be the case in the present or future.
“uncritically draws an inference from what has been true in the past to
what will be true in the future”
Time Shift Errors
“the argument confuses the percentage of the budget spent on a program
with the overall amount spent on that program”
Numbers and Percentage Errors
Which one of the following is a questionable
argumentative strategy employed in the editorial’s
argument?
Flaw in the reasoning
The argument is most vulnerable to criticism on
which one of the following grounds?
Flaw in the reasoning
The reasoning in the activist’s argument is flawed
because that argument
Flaw in the reasoning
The reasoning in the philosopher’s argument is
flawed because the argument
Flaw in the reasoning
The reasoning in the argument is flawed in that the
argument
Flaw in the reasoning
The reasoning in the astronomer’s argument is flawed
because this argument
Flaw in the reasoning
The reasoning in the argument is most vulnerable to
criticism on the grounds that the argument
Flaw in the reasoning
The reasoning in the argument is flawed in that the
argument
Flaw in the reasoning
Parallel Reasoning questions ask you to
identify the answer choice that contains
reasoning most similar in structure to the reasoning in the stimulus.
“Which one of the following is most closely parallel in its reasoning to
the reasoning in the argument above?”
Parallel Reasoning Questions
“Which one of the following exhibits a pattern of reasoning most similar
to that exhibited by the argument above?”
Parallel Reasoning Questions
“Which one of the following arguments is most similar in its logical
features to the argument above?”
Parallel Reasoning Questions
“The structure of the reasoning in the argument above is most parallel to
that in which one of the following?”
Parallel Reasoning Questions
“Which one of the following arguments is most similar in its pattern of
reasoning to the argument above?”
Parallel Reasoning Questions
The stimulus for a Parallel Reasoning question can contain either
valid or
invalid reasoning
“The flawed reasoning in which one of the following is most similar to
the flawed reasoning in the argument above?”
Parallel Flaw
When a Parallel Reasoning stimulus contains flawed reasoning, we
identify it as
a Parallel Flaw question.
“The questionable pattern of reasoning in the argument is most similar to
that in which one of the following?”
Parallel Flaw
In Parallel Reasoning questions, the topic or subject matter in the
stimulus and the answer choices is
irrelevant because you are looking
for the argument that has a similar pattern of reasoning. Often, same subject answer choices are used to attract the student who fails to focus
on the reasoning in the stimulus.
In parallel flaw order of presentation of the premises and conclusion in the stimulus
is
also irrelevant.
In parallel flaw elements that must be paralleled,
- The Method of Reasoning
- The Validity of the Argument
- The Conclusion
- The Premises
Because Parallel
Reasoning
questions are so
long and time consuming, they
often appear
toward the end of
a section. This
placement is the
result of an old
psychometric
trick:
just when a
test taker is
feeling pressured
to work faster
and finish the
section, the test
makers slip in a
time-consuming
question that
slows students
down and causes
frustration.
The following list outlines the four tests you can use to evaluate
answers, in rough order of their usefulness:
(Parallel Flaw)
- Match the Method of Reasoning
- Match the Conclusion
- Match the Premises
- Match the Validity of the Argument
Which one of the following exhibits a flawed pattern
of reasoning most similar to that in the argument
above?
Parallel Flaw
The flawed pattern of reasoning in the argument
above is most similar to that in which one of the
following?
Parallel Flaw
The pattern of reasoning displayed in the argument
above is most closely paralleled by that in which one
of the following arguments?
Parallel Flaw
If none of the four tests of analysis reveals the answer, or if nothing stands out
to you when you examine the argument, you can always fall back on (Parallel Flaw)
on describing
the stimulus in abstract terms
The questionable reasoning in the argument above is
most closely paralleled by that in which one of the
following?
Parallel Flaw
If all else fails, create a short statement that summarizes
(Parallel Flaw)
the “action” in the
argument. Then, take the abstraction and compare it to each argument. Does it
match your generalized version of the stimulus? If not, the answer is incorrect
Which one of the following arguments exhibits
flawed reasoning most similar to that exhibited by
the argument above?
Parallel Flaw
The flawed reasoning in which one of the following
is most similar to that in the commentator’s
argument?
Parallel Flaw
Which one of the following arguments has a flawed
pattern of reasoning most like the flawed reasoning
in the argument above?
Parallel Flaw
Which one of the following exhibits both of the
logical flaws exhibited by the argument above?
Parallel Flaw
Misconception #1: Increasing percentages automatically lead to
increasing numbers. Most people assume that if a percentage becomes larger, the number that
corresponds to that percentage must also get larger. This is not
necessarily true because the overall size of the group under discussion
could get smaller
If the percentage
increases but the
corresponding
number
decreases, then
the overall total
must have
decreased.
Misconception #2: Decreasing percentages automatically lead to
decreasing numbers. Just because a percentage decreases does not necessarily mean that the corresponding
number must become smaller.
Misconception #3: Increasing numbers automatically lead to
increasing
percentages. Just as increasing percentages do not automatically translate into
increasing numbers, the reverse is also true.
Misconception #4: Decreasing numbers automatically lead to
decreasing
percentages.
Misconception #5: Large numbers automatically
mean large
percentages, and small numbers automatically mean
small percentages.
Misconception #6: Large percentages automatically mean large
numbers, and
small percentages automatically mean
small numbers.
Numerical situations normally hinge on three elements:
an overall total, a
number within that total, and a percentage within the total. LSAT problems will
often give you one of the elements, but without at least two elements present,
you cannot make a definitive judgment about what is occurring with another
element. When you are given just percentage information, you cannot make a
judgment about numbers. Likewise, when you are given just numerical
information you cannot make a judgement about percentages.
Knowledge of a
percentage is
insufficient to
allow you to make
a determination
about the size of
the number
because
the
exact size of the
overall total is
unknown, and
changes in the
overall total will
directly affect
the internal
numbers and
percentages.
Words used to introduce numerical ideas:
Amount, Quantity, Sum, Total, Count, Tally
Words used to introduce percentage ideas:
Percent, Proportion, Fraction, Ratio, Incidence, Likelihood, Probability, Segment, Share
If the stimulus contains percentage or proportion information only, avoid
answers that contain hard numbers.
If the stimulus contains only numerical information, avoid answers that
contain percentage or proportion information.
If the stimulus contains both percentage and numerical information, any
answer choice that
contains numbers, percentages, or both may be true.
The logical opposite is the statement
requiring the least amount of “work” to
negate the original statement.
The polar opposite typically goes much further than
logical opposite.
“All” logical opposite
Not All
“Some” logical opposite
None
“Everywhere” logical opposite
Not Everywhere
“always” logical opposite
“Not always”
“somewhere” logical opposite
No where
“Never” logical opposite
Sometimes
To negate a conditional statement you must show that
the necessary condition is
not in fact necessary.
Watch for answers starting with the phrase “at least one” or “at least
some.” when an Assumption answer choice starts with either of the above constructions the chances are unusually high that
the answer will be correct. However, if you spot an answer with that construction, do not simply assume the answer is correct; instead, use the proper negation (“None”) and check the answer with the
Assumption Negation Technique
In assumption avoid answers that claim an idea was the most important consideration
for the author. These answers typically use constructions such as “the primary
purpose,” “the top priority,” or “the main factor.” In every Assumption
question these answers
have been wrong. And, unless, the author
specifically discusses the prioritization of ideas in the stimulus, these
answers will continue to be wrong because an author can always claim
that the idea under discussion was very important but not necessarily the
most important idea.
Words that introduce numerical ideas:
Amount, Quantity, Sum, Total, Count, Tally
Words that introduce percentage ideas:
Percent, Proportion, Fraction, Ratio, Incidence, Likelihood, Probability, Segment, Share
Use the following general rules for Must Be True questions: Numbers or Proportions
- If the stimulus contains percentage or proportion information only, avoid
answers that contain hard numbers. - If the stimulus contains only numerical information, avoid answers that
contain percentage or proportion information. - If the stimulus contains both percentage and numerical information, any
answer choice that contains numbers, percentages, or both may be true.
Use the following general rules for Weaken and Strengthen questions:
To weaken or strengthen an argument containing numbers and percentages, look carefully for
Information about the total amount(s)— does the argument make an assumption based on one of the misconceptions discussed earlier?
Evaluate the Argument questions ask you to consider the question, statistic, or
piece of information that would best.
help determine the logical validity of the
argument presented in the stimulus. You must select the answer choice that decides whether the argument is good or bad.
Evaluate the Argument question stems almost always use the word
“evaluate”
or a synonym such as “judge” or “assess,” but the intent is always identical: the
question stem asks you to identify the piece of information that would be most
helpful in assessing the argument
“The answer to which one of the following questions would contribute
most to an evaluation of the argument?”
Evaluate the Argument
“Clarification of which one of the following issues would be most
important to an evaluation of the skeptics’ position?”
Evaluate the Argument
“Which one of the following would be most important to know in
evaluating the hypothesis in the passage?”
Evaluate the Argument
“Which one of the following would it be most relevant to investigate in
evaluating the conclusion of George’s argument?”
Evaluate the Argument
“Which one of the following would it be most helpful to know in order
to judge whether what the scientist subsequently learned calls into
question the hypothesis?”
Evaluate the Argument
The Variance Test
is a very powerful
tool for
attacking
Evaluate the
Argument
questions.
The Variance Test consists of
supplying two polar opposite responses to the
question posed in the answer choice and then analyzing how the varying
responses affect the conclusion in the stimulus. If different responses produce
different effects on the conclusion, then the answer choice is correct, . If different
responses do not produce different effects, then the answer choice is incorrect.
Evaluate the
Argument stimuli
always contain
a conclusion.
Assumption
questions—use
the
Assumption
Negation
Technique
Justify
questions—use
the Justify
Formula.
Evaluate the
Argument
questions—use
the Variance Test.
The Variance Test should only be applied to
Contenders (to determine which one is correct) or to the answer choice you believe is correct (to confirm your
selection).
In Cannot Be True questions your task is to
identify the answer choice that
cannot be true or is most weakened by the information in the argument.
“If the statements above are true, which one of the following
CANNOT be true?”
Cannot be true
“The argument can most reasonably be interpreted as an
objection to which one of the following claims?”
Cannot be true
“The information above, if accurate, can best be used as
evidence against which one of the following hypotheses?”
Cannot be true
“The statements above, if true, most seriously undermine which
one of the following assertions?”
Cannot be true
The phrase “must be false” is functionally identical to
“cannot be true.”
The use of this wording is just one more way for the test makers to
present you with unusual phrasing.
Stating that the answer could be true EXCEPT. This construction is frequently used to
convey the Cannot Be True
concept. If the four incorrect answers could be true, then the one
remaining answer must be the opposite, or cannot be true.
“If the statements above are true, then which one of the
following must be false?”
cannot be true/must be false
As with most Cannot Be True questions, the stimulus does not
contain an
argument. Instead, a fact pattern is presented and you are tested on your
knowledge of those facts.
In Cannot Be True questions, the stimulus will often
supply enough information for you to determine that certain outcomes
must occur (for example, increasing market share while the overall
market size remains constant results in greater sales). The correct answer
then
violates this outcome.
Many different scenarios can occur in Cannot Be True questions
featuring conditional statements, except the following:
The sufficient condition occurs, and the necessary condition
does not occur.
when a conditional statement is made in a Cannot Be True
question stimulus, you should actively seek answer choices that show that the
The sufficient condition occurs, and the necessary condition
does not occur.
Incorrect answers often play upon the possibility that the necessary condition occurs but the
sufficient condition does not occur. Those
scenarios could occur and are thus incorrect.
If the statements above are true, each of the following
could also be true EXCEPT:
must be false/cannot be true
If the statements above are true, which one of the
following CANNOT be true?
must be false
If all the statements above are true, then which one of
the following must be false?
must be false
Point at Issue stimuli are comprised of
two speakers
who disagree about an issue that is generally ethical or decision-oriented in
nature, not factual. The question stem directs you to choose the answer that
describes the point of disagreement between the two speakers, or to identify a
statement that the two speakers would disagree is true.
“Which one of the following most accurately expresses the point at issue
between Tom and Mary?”
Point at issue
“Which one of the following most accurately represents what is at issue
between Jorge and Ruth?”
Point at issue
“The dialogue above lends the most support to the claim that Sherrie
and Fran disagree with each other about which one of the following
statements?”
Point at issue
“On the basis of their statement, Logan and Mendez are committed to
disagreeing over whether”
Point at issue
Incorrect Answers in Point at Issue Questions
- Ethical versus Factual Situations
- Dual Agreement or Dual Disagreement
- The View of One Speaker is Unknown
In Point at Issue Questions When a stimulus addresses an issue that is ethical in nature, answer choices that are factual in nature
cannot be true.
In Point at Issue Questions often, incorrect answer choices will supply statements that both
speakers will agree with, or that both speakers will disagree with. These
answer choices are typically quite attractive because they raise issues
that are addressed in the stimulus and therefore they require some
analysis
In Point at Issue Questions Another crafty trick used by the test makers is to create an answer where
the view of
only one of the speakers is known. In these instances the
view of the speaker is unknown because the speaker’s comments did not
address the issue in the answer choice. Since the correct answer must
contain a point of disagreement, these “one unknown” answers are
always incorrect since there is no way to determine that the other
speaker disagrees
Point at Issue
questions—use
the Agree/
Disagree Test.
The Agree/Disagree Test
The correct answer must produce responses where one speaker would say “I agree, the statement is correct” and the other speaker would say,
“I disagree, the statement is incorrect.” If those two responses are not produced, then the answer is incorrect.
The Agree/Disagree Test crystallizes the essence of Point at Issue questions by
forcing you to
concretely identify the elements that determine the correct
answer.
On the basis of their statements, Shanna and Jorge
are committed to disagreeing about the truth of
which one of the following statements?
Point at issue
Which one of the following is a point at issue
between the nutritionist and the consumer advocate?
Point at issue
Hazel and Max disagree over whether
Point at issue
Which one of the following is an issue about which
the two councilpersons disagree?
Point at issue
Franklin’s and Tomeka’s statements provide the most
support for holding that they disagree about the truth
of which one of the following?
point at issue
Lea’s and Susan’s remarks provide the most support
for holding that they disagree about whether
point at issue
The word
“proposition” or
“precept” can be
used in place of
“principle.”
“Which one of the following judgments most closely conforms to the
principle above?” (Must-PR)
Must-Principle
“Which one of the following judgments best illustrates the principle illustrated by the argument above?” (Must-PR)
Must-Principle
“The principle above, if established, would justify which one of the
following judgments?” (Must-PR)
Must-Principle
“Which one of the following principles most helps to justify the reasoning above?” (Strengthen-PR)
Strengthen-Principle
“The information above most closely conforms to which one of the following principles?” (Strengthen-PR)
Strengthen-Principle
“Which one of the following most accurately expresses the principle underlying the argumentation above?” (Justify-PR)
Justify-Principle
“Each of the following principles is logically consistent with the
columnist’s conclusion EXCEPT:” (Cannot-PR)
Cannot-Principle
Principle questions (PR) are not a separate question type but are instead an
“overlay” that appears in a variety of question types.
A principle is a broad rule that specifies
what actions or judgments are correct in certain situations.
Since a principle is by definition a broad rule (usually conditional in nature), the
presence of the Principle indicator serves to broaden the scope of the question.
The question becomes more
abstract, and you must analyze the problem to
identify the underlying relationships.
Because
principles must
retain broad
applicability and
must typically
meet a condition
to apply, they are
often
conditional
statements.
However, there
are exceptions,
such as with
causal principles.
Must Be True Principle Questions
In these questions you must use the principle presented in the stimulus
and then apply it to the situation in each answer choice (one principle
applied to five situations). Although these are Must Be True questions,
the presence of the principle designation broadens the question, and the
answer choice can address a scenario not specifically included in the
stimulus; your job is to find the answer that follows from the application
of the principle.
Strengthen/Justify Principle Questions
In these questions each answer choice contains a principle that acts as
an additional, broad premise that supports or proves the conclusion.
A principle is a broad rule that specifies what
actions or judgments are correct in
certain situations. The degree of generality of principles can vary considerably,
and some are much narrower than others.
