Lesson Seven: Logical Reasoning & Logical Games

Question 1

Method of Reasoning (Argument Part) Questions

Answer 1

Ask you to identify how a cited portion of the text fits into the overall structure of the author’s argument.

Right Answer: describes the cited portion’s structure in relation to the rest of the argument (the purpose it serves in the rest of the argument).

Question 2

Given that the Method of Reasoning questions are questioning you about a cited portion’s role in the argument, the right answer will likely have the words “________,” “___________,” or “____________” in them.

Answer 2

premise; argument; conclusion

Question 3

Method of Reasoning Questions

Answer 3

• Abstract Must Be True Question
• Family #1 (Prove) question stems: BASED on the stimulus, does the answer choice follow?

Stimulus
↓
Answer Choice

Question 4

Flaw in the Reasoning Questions

Answer 4

• Also apart of Family #1 (Prove) question stems.
• Exactly like Method of Reasoning questions, except here there is a flaw in the reasoning the stimulus uses. Some part of the argument in the stimulus is inherently flawed; this is good.
• The question stem will ask you to find the flaw in reasoning, which means you have a chance to find the flaw in the argument before diving into your answer choices.
• Right Answer Choice: identifies the error in reasoning and describes in general terms.

Question 5

Remember, Method of Reasoning questions ALWAYS contain an _______________.

Answer 5

argument.

Question 6

Example Question Stems for Method of Reasoning Questions
- “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.”

Question 7

Phrasing Indicating Flaw in the Reasoning Questions
- “The reasoning is flawed…”
- “the argument is vulnerable,”
- “Which one of the following most accurately describes a flaw in the argument’s reasoning?”
- “The reasoning in the argument is most vulnerable to the criticism on the grounds that.”

Question 8

Common Errors of Reasoning Explained:

1) Errors of Conditional Reasoning
(1. Mistaken Reversal & Negation)

Answer 8

Mistaken Reversal: If the necessary condition occurs, then the sufficient condition occurs.

Mistaken Negation: If the sufficient condition does not occur, then the necessary condition does not occur.

Question 9

Mistaken Negation Example Answer Choice:
- “Taking the nonexistence of something as evidence that a necessary precondition for that thing also did not occur.”

Mistaken Reversal Example Answer Choice:
- “Mistakes being sufficient to justify punishment for being required to justify punishment.”

Question 10

Common Errors of Reasoning Explained:

1) Errors of Conditional Reasoning
(2. Confusing the ____________ Condition with the ____________ Condition)
“confuses a _____________ condition with a required condition.”

(2. Confusing the ____________Condition with the _____________ Condition)
“treats something that is _____________ to bring about that state of affairs as something that is _____________ to bring about that state of affairs.”

Answer 10

Sufficient; Necessary
sufficient; required

Necessary; Sufficient
necessary; sufficient

Question 11

KEEP IN MIND: Many of these Flaw in the reasoning questions that use conditional reasoning errors, use wording such as “_______________,” and “______________.” So, be sure to scan your answer choices for answers that use “______________” and “_____________”.

Answer 11

sufficient; necessary; sufficient; necessary

Question 12

Common Errors of Reasoning Explained:

2) Mistaken Cause and Effect
(1. Assuming a Causal Relationship Based on a Sequence of Events)

Answer 12

The stimulus may present a situation wherein one event just simply occurs before another without those two variables necessarily sharing a relationship, but the author assumes takes the one event happening before another as causal.

(such that the first event is the cause, and the latter an effect).

Question 13

Common Errors of Reasoning Explained:

2) Mistaken Cause and Effect
(2. Assuming a Causal Relationship when only a Correlational Exists)

Answer 13

Mistakes 2 events that happen within relatively the same time, as one event being the cause of another.

“assumes a causal relationship where only a correlational has been indicated.”

Question 14

Common Errors of Reasoning Explained:

2) Mistaken Cause and Effect
(3. Failure to Consider an Alternate Cause for the Stated Effect, or an Alternate Cause for both the Cause and Effect)

Answer 14

Argument doesn’t consider that the effect may not be the result of the stated cause, but possibly a new alternate cause
OR
that both the cause and effect share a spurious relationship with a third cause that prompted the stated cause and effect.

“overlooks the possibility that the same thing may causally contribute both to education and good health.”

Question 15

Common Errors of Reasoning Explained:

2) Mistaken Cause and Effect
(4. Failure to Consider the Events may be Reversed)

Answer 15

Argument mistakes the state cause for the effect, and the stated effect for the cause.

“the author mistakes an effect for a cause” & vice versa.

Question 16

KEEP IN MIND: Many of the answer choices you’ll see in Flaw questions with a causal error in reasoning use the words “_________,” “__________,” or both. This is because the LSAT test makers really can’t find/substitute in any other words when describing a causal error. So, be sure to scan your answer choices for the words “__________,” “__________” or both.

Answer 16

cause; effect; cause; effect

Question 17

Common Errors of Reasoning Explained:

3) Source Argument

Answer 17

• Aka, “Ad-Hominem” argument.
• Attacks the source of the argument, rather than the argument itself (degrades the character of the purveyor of the argument instead of the arg.)

Question 18

Two ways in Which the Source Argument Error can be Committed:

Answer 18

• Attacking the motives of the source.
• Attacking the actions of the source.

Question 19

Examples of Source Argument Reasoning Errors in Answer Choices:
- “makes an attack on the character of their opponents.”

• “it is directed against the proponent of the claim rather than the claim itself.”
• “he’s directing his criticism against the person making the argument rather than directing the criticism at the argument itself.”

Question 20

Common Errors of Reasoning Explained:

4) Circular Reasoning

Answer 20

-The premises support the conclusion EQUALLY AS MUCH AS the conclusion supports the premises.

• Classic example of repeating what the premises say as one’s conclusion (reaffirming what the premises say in the conclusion).
• “I am telling the truth because I’m not lying.”

Question 21

Examples of Circular Reasoning Argument Error in Answer Choices:
- “it assumes what it seeks to establish.”

• “argues circularly by assuming the conclusion is true in restating the premises.”
• “presupposes the truth of what it sets out to prove.”
• “the argument assumes what its attempting to demonstrate.”
• “it offers, in place of support for its conclusion, a mere restatement of that conclusion.”

Question 22

Common Errors of Reasoning Explained:

5) Errors in the Use of Evidence: when LSAT test makers miss-assess the ____________ of evidence.

Answer 22

force

Question 23

Common Errors of Reasoning Explained:

5) Errors in the Use of Evidence:
(1. Lack of evidence for a position is taken to prove that position is false)

Answer 23

When the author falsely assumes that because there’s no evidence to prove a position true, then the position itself is undeniably false.

“The White House has failed to offer any evidence that a trade agreement has been reached between the United States and China, so no such agreement exists.”

Obviously, the lack of confirming evidence does not prove the agreement does not exists.

Question 24

5.1. Examples Answer Choices
- “treats failure to prove a claim as constituting a denial of the claim.”

• “taking a lack of evidence for a claim as evidence undermining that claim.”

Question 25

Common Errors of Reasoning Explained:

5) Errors in the Use of Evidence:
(2. Lack of evidence against a position is taken to prove that position is true.)

Answer 25

When the author falsely assumes that because there is no evidence against a certain position, then that position must be undeniably true.

“There is no evidence against God, therefore God exists.”

The lack of evidence disproving a position doesn’t result in the certainty that the position is altogether true.

Question 26

5.2. Example Answer Choices
- “treating the failure to establish a claim as false as equivalent to treating the claim as true.”

Question 27

Common Errors of Reasoning Explained:

5) Errors in the Use of Evidence:
(3. Some evidence against a position is taken to prove that position is false.)

Answer 27

When the author falsely assumes that because certain evidence against a position is true, that is enough to prove the position is undeniably false.

“Some evidence” is supposed to weaken the position, it’s not enough to prove that the entire argument is false.

“Some historians claim that a lengthy drought preceded the fall of the Aztec Empire. But we know from Aztec writing that in at least one year during the supposed drought there was minor flooding. Thus, the claim that there was a lengthy drought prior to the fall of the Aztec Empire is false.”
- The evidence of minor flooding weakens the argument of drought, but doesn’t completely invalidate it.

Question 28

5.3. Example Answer Choices
- “it confuses undermining an argument in support of a given conclusion with showing that the conclusion itself is false.”

Question 29

Common Errors of Reasoning Explained:

5) Errors in the Use of Evidence:
(4. Some Evidence For a Position Is Taken to Prove That Position is True)

Answer 29

Opposite of 5.3.
When the author falsely assumes that because certain evidence supports a position, then the position itself is undeniably true.

“Some evidence,” in this case, is meant to strengthen the position, it’s not enough to prove the position is completely true.

“We know that the defendant was in the vicinity of the robbery when the robbery occurred. Therefore, the defendant is guilty of the robbery.”
- The evidence of the defendant being within the area of the scene certainly helps to incriminate the defendant, but doesn’t mean he’s guilty of the robbery.

Question 30

5.4. Example Answer Choices
- “the argument takes evidence showing merely that its conclusion could be true to constitute evidence showing that the conclusion actually is true.”

Question 31

Common Errors of Reasoning Explained:

6) General Lack of Relevant Evidence for the Conclusion

Answer 31

When LSAT authors misuse information by
1) not providing information for the conclusion.
2) providing irrelevant information for the conclusion.

Question 32

Example LSAT Stimulus:
“Some critics claim that scientific progress has increased the polarization of society and alienated large segments of the population. But these critics are wrong because even a cursory glance at the past shows that society is always somewhat polarized and some groups are inevitably alienated.”

Explain what the lack of relevant evidence is in this stimulus.

Answer 32

Premise: Last Sentence
Conclusion: First Sentence

What the author uses as proof as to why the first sentence (conclusion) is wrong, is irrelevant. The second sentence provides irrelevant information; it doesn’t talk about the increase in polarization and alienation as a result of scientific progress, they merely say ‘it’s always been around.’

Question 33

6) Example Answer Choices:
- “the author cites irrelevant data.”

• “draws a conclusion that is broader in scope than is warranted by the evidence advanced.”
• “It fails to give any reason for the judgement it reaches.”
• “It introduces information unrelated to its conclusion as evidence in support of that conclusion.”

Question 34

Common Errors of Reasoning Explained:

7) Exceptional Case / Overgeneralization

Answer 34

Error that occurs when the author 1) takes a sample from a limited number of instances, and 2) makes a sweeping conclusion about all instances.

“Me and 2 of my friends got shortchanged at that store. Therefore, everyone gets shortchanged at that store.”

Question 35

7) Example Answer Choices:
- “Supports a universal claim on the basis of a single example.”

• ” The argument generalizes from too small a sample of cases.”
• “Bases a general claim on a few exceptional instances.”

Question 36

Common Errors of Reasoning Explained:

8) Errors of Composition and Division

Answer 36

Composition Error:
Applying characteristics of the constituent part(s) to the whole.

Ex. “Every party I attend is fun and exciting. Therefore, my life is fun and exciting.”

Division Error:
Applying characteristics of the whole to constituent parts.

Ex. “The United States is the wealthiest country in the world. Thus every citizen in America is wealthy.”

Question 37

8) Composition Error – Example Answer Choices:
- “Assuming that because something is true of each of the parts of a whole, it is true of the whole itself.”

8) Division Error – Example Answer Choices:
- “Presumes, without providing any justification, that what’s true of the whole must be true of the constituent parts.

Question 38

Common Errors of Reasoning Explained:

9) Straw Man

Answer 38

The opposition to an argument puts forth a position, and the author distorts the oppositions argument, and refutes the distorted version (as though they’ve refuted the initial [real] version).

The distorted version of the argument is metaphorically built on “straws,” making the argument weaker (easier to knock down).

Question 39

Indicators of the Straw Man fallacy in an argument:

Answer 39

“What you’re saying is…”
“If I understand you correctly”

Question 40

What’s the difference between Composition Error v. Overgeneralization?

Answer 40

Overgeneralization: This only refers to a single class of things (independently) (ex. shortchange store)

Composition Error: Takes a characteristic of one thing applies it to a number of different things (ex. parties & life being fun and exciting)

Question 41

*KEEP IN MIND: Be WARY of answers to Flaw questions that refer to the _____________ information from the stimulus. Remember, the correct answer choice is only supposed to _____________ the error in reasoning and ____________ it in ____________ terms.

Answer 41

specific; identify; describe; general

Question 42

Common Errors of Reasoning Explained:

10) Survey Errors
(1. The survey used a bias sample)

Answer 42

• Pretty self explanatory.
• If the sample is bias (such that the demographic is concentrated on a certain type of people), results could be skewed, and it wouldn’t be representative of the general public.

Question 43

Common Errors of Reasoning Explained:

10) Survey Errors
(2. The survey questions are improperly constructed)

Answer 43

• Survey questions that are confusing or misleading will likely result in inaccurate answers.
• If the survey questions are improperly constructed, how can you expect respondents to answer accurately.

Question 44

Common Errors of Reasoning Explained:

10) Survey Errors
(3. Respondents to the survey give inaccurate responses)

Answer 44

• People may not tell the truth on surveys.
• Questions to which many people will likely give you a dishonest answer include 1) “How old are you?,” and 2) “How much do you make per year?”
• Dishonest answers will yield inaccurate results.

Question 45

10) Example Answer Choices:
- “uses evidence drawn from a sample that may well be unrepresentative.”
- “generalizes from an unrepresentative sample.”

Question 46

Common Errors of Reasoning Explained:

11) Uncertain Use of a Term or Concept

Answer 46

The LSAT makers are supposed to use vocabulary is a constant, coherent manner.
Using terms or concepts in an non-constant, incoherent manner makes the stimulus confusing.

Question 47

Example LSAT question:
“Some people claim that the values that this country was built on are now being ignored by modern-day corporations. But this is incorrect. Corporations are purely profit driven enterprises beholden only to their shareholders, and as such they can only assess objects based on their value.”

Describe what the uncertain use of a term or concept is.

Answer 47

They use the word “value” in two different context. “Value” in the first sentence refers to principles, moral and ethical. Value in the last sentence refers to finances, which encompasses a monetary meaning.

Question 48

11) Example Answer Choices:
- “Depending on ambiguous use of a key term.”

• “it confuses two different meanings of the word ‘______”.”
• “relies on interpreting a key term in two different ways.”
• “allows a key term to shift meaning from one use to the next.”

Question 49

Common Errors of Reasoning Explained:

12) False Dilemma

Answer 49

Occurs when the author falsely assumes that there’s only 2 possible courses of action (and that no other course of action is possible), when there could be others.

Question 50

Example LSAT Question:
“Recent accidents within the oil industry have made safety of operation a critical public safety issue. Because the industry cannot be expected to police itself, the government must step in and take action.”

Describe what the False Dilemma is?

Answer 50

This stimulus assumes to ensure public safety in light of recent oil industry accidents, either industry policing must be enforced, and if not them, then government action. But we know there’s more than those two options that could conceivably help ensure safety in the industry (ex. watchdog groups).

Question 51

Common Errors of Reasoning Explained:

13) Internal Contradiction

Answer 51

When the author makes conflicting statements (in the same argument).

Question 52

Example LSAT Question:
“Everyone should join our country club, its’ an exclusive group that links many of the influential members of the community.”

Where’s the internal contradiction

Answer 52

“Everyone should join” contradicts “exclusive group”

Question 53

13) Example Answer Choices:
- “Bases a conclusion on claims that are inconsistent with each other.”

• “the author makes incompatible assumptions.”
• “the author introduces information that actually contradicts the conclusion.”

Question 54

Common Errors of Reasoning Explained:

14) Appeal Fallacies
(1. Appeal to Authority)

Answer 54

When the author appeals to authority when giving evidence to support a conclusion.
- this can be a trap for a couple of reasons:
1) appealing to an authority figure whose expertise are irrelevant to the subject matter of the argument is an error (it doesn’t help the argument).

2) appealing to an authority figure (perhaps, even, someone who does have the relevant expertise) isn’t enough provide sufficient justification for a conclusion.

Question 55

14.1. Example Answer Choices:
“The judgement of experts is applied to a matter in which their expertise is irrelevant.”

“accepts a claim on mere authority, without requiring sufficient justification.”

Question 56

Common Errors of Reasoning Explained:

14) Appeal Fallacies
(2. Appeal to Popular Opinion / Appeal to Numbers)

Answer 56

Error that says because the majority believes a certain position is true, then the position must be true.

This concludes that a certain position is true without reaching the conclusion in a logical means (through logical reasoning).

“A recent poll states that 75% of Americans believe that Microsoft is a Monopoly. Antitrust law states that monopolies have a deleterious effect on the marketplace, and therefore Microsoft should be controlled or broken into smaller pieces.”

This argument relies on the appeal to numbers because the 75% is the majority of the poll taken who BELIEVE Microsoft is a monopoly, and it relies on this solely to prove that Microsoft is in fact a monopoly.

Question 57

14.2. Example Answer Choices

“it treats popular opinion as if it constituted conclusive evidence for a claim.”
“a claim is inferred to be false merely because the majority of people believe it to be false.”

Question 58

Common Errors of Reasoning Explained:

14) Appeal Fallacies
(3. Appeal to Emotion)

Answer 58

When the author of the argument relies on emotionally charged language to persuade the test taker and prove the conclusion.

“Officer, please don’t give me a ticket for speeding. Last month I’ve been fired from my job kicked out of my apartment, and my car broke down. I don’t deserve this!”

Question 59

14.3. Example Answer Choices

“attempts to persuade by making emotional appeal.”
“the argument appeals to emotion rather than reason.”

Question 60

Common Errors of Reasoning Explained:

15) False Analogy

Answer 60

We know that an analogy is supposed to compare two things. So a false analogy is comparing two things/situations that don’t share any likeness.

Question 61

15) Example Answer Choices:

“treats as similar two cases that are different in a critical respect.”
“treats two kinds of things that differ in important respects as if they don’t differ.”

Question 62

Common Errors of Reasoning Explained:
16) Time Shift Errors

Answer 62

Faulty assumption that just because something was a certain way in the past, it is a certain in the present, and will be in the future.

“The company has always reimbursed me for meals when I’m on a business trip, so they will certainly reimburse me for meals on this business trip.”

Question 63

16) Example Answer Choices:

“treats a claim about what is the case as if it were a claim about what has been the case for an extended period.”

Question 64

Common Errors of Reasoning Explained:
17) Numbers and Percentage Errors:

When the author uses percentages to make a judgement about a definite ____________.
OR
When the author uses _____________ information to make a judgement about the percentage represented by that _____________.

The concept is a bit abstract, so let’s break it down with an example:
Let’s say in one hand you have 10 black marbles, and 10 red marbles. So you’re percentage of black v. red is 50/50 (50%). Now let’s say (in this hypothetical problem), you suddenly have 75% red marbles. Is this because you gained more red marbles?! Not necessarily. It could be that you lost some black marbles.

If the stimulus is about numbers (or refers to numbers), the RIGHT ANSWER CHOICE is going to have numbers, NOT PERCENTAGES. (In a stimulus about numbers, the answer choices are going to try to trap you with answers about percentages).

If the stimulus is about percentages, then your right answer choice will also have percentages, NOT NUMBERS (it’s not going to make judgements about percentages [loss or increase] with the use of numbers). (In a stimulus about percentages, the answer choices are going to try to trap you with answers about numbers).

If an answer choice deals with numbers increasing or decreasing, or percentages increasing or decreasing, the right answer choice will likely deal with the total.

Answer 64

quantity; quantity; quantity

Question 65

17) Example Answer Choices:
- “the argument confuses the percentage of the budget spent on a program with the overall amount spent on that program.”

Question 66

– LOGIC GAMES–

Question 67

Grouping / Linear Games

Answer 67

Games that include both grouping and linear aspects.

Question 68

Describe the Hierarchy in Grouping/ Linear Games

Answer 68

Grouping always comes first, linearity always comes second (Hierarchy below:)

Grouping
↓
Linearity

Question 69

If in a Grouping/Linear game, your game is unbalanced: ____________, you must narrow your set of variables to how many can be selected for a game, THEN place those variables in a diagram with a _______________ element. IN THESE OVERLOADED GAMES, YOU NEED TO CONSTRUCT AN ___ AND _____ TABLE.

Answer 69

overloaded; linear; IN; OUT

Question 70

When a question presents one of the variables as _____________ (by the rules or in a local question) find out how that ___________ the other variables that could be played.

Answer 70

presented; affects

Question 71

Let’s say you have a game that has 9 variables and 7 slots. You know that any seven of the nine variables are chosen for the game, then the other two are _______, and you place them in the ______ section of the ____ and _______ table.

Answer 71

out; out; in; out

Question 72

The Approach to take to Grouping / Linear, Unbalanced: Overloaded Games

Answer 72

1) Group your variables first: Figure out which variables MUST be selected, and what are your most powerful variables.

2) Then order your variables: Manipulate your variables, make inferences, and solve your question.