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bible的第二章翻了N遍，一个字也没记下来。决定换一种学习方法--写读书笔记，如果有跟我一样看不懂bible的童鞋也可以一起讨论一下。今天先从第2章开始。使用的教材是一位前辈上传的，如下
http://forum.chasedream.com/foru ... hlight=lsat%2Bbible
Powerscore, LSAT 逻辑圣经
共20章，网上建议的学习时间是一个半月，每天4，5小时。但因人而异
----------------------------------------------------------------------------------------------
(第2章) The Basics of Logical Reasoning
(第3章) The Question Stem and Answer Choices the Question Stem
(第4章) Must Be True/Most Supported P66
(第5章) Main Point
(第6章) Conditional Reasoning
(第7章) Weaken
(第8章) Cause and Effect Reasoning
(第9章) Strengthen, Justify, and Assumption
(第10章) Resolve the Paradox Questions
(第11章) 这章被切了！？
(第12章) Method of Reasoning Questions P322
(第13章) Flaw in the Reasoning Questions P350---超级重要的一章，做题时经常看不出来为什么错(第14章) Parallel Reasoning Questions P380
(第15章) Numbers and Percentages
(第16章) Evaluate the Argument
(第17章) Cannot Be True
(第18章) Point at Issue
(第19章) Principle Question
(第20章) Section Strategy and Management
第二章 逻辑的基础（The Basics of Logical Reasoning）
逻辑问题的分解（The Parts of a Logical Reasoning Question）
Every Logical Reasoning question contains three separate parts: the stimulus（背景/条件）,
the question stem（提干）, and the five answer choices（选项）.
如何解析问题（Approaching The Questions）
读题时按照题目给的顺序读
分析条件（Analyzing the Stimulus）
读条件时的方法
-要纵向展开，但不要横向展开。
-要注意的2点：速度与耐心。 能够驾驭这两点的人不但可以注意每个文章细节又可保证能够答完题。
-理清条件中的结构，以便之后的解题
条件的内容（Stimulus Topics）
逻辑的条件范围很广，但不要担心，答题并不需要某个专业的知识。
论述vs事实 （Arguments versus Fact Sets）逻辑题中的条件分为种：论述条件 和 事实条件
-论述条件的特点：虽然里面有陈述，但陈述句之间有联系。比如从A中可以推出B。给个例句
argument: All professors are ethical. Mason is a professor. So Mason is ethical.
-事实条件的特点：都是陈述句，每句话之间没有因果关系。
The Jacksonville area has just over one million residents. The
Cincinnati area has almost two million residents. The New York area
has almost twenty million residents.
目标1：决定题中用的是论述条件还是事实条件。
Primary Objective #1: Determine whether the stimulus
contains an argument or if it is only a set of factual statements.
目标2：如果条件包括一个论述，要区别这个论述的结论。如果条件包括事实，要仔细看每个事实。
Primary Objective #2: If the stimulus contains an argument,
identify the conclusion of the argument. If the stimulus
contains a fact set, examine each fact.
附加条件的表示词（Additional Premise Indicators）
反例的表示词（Counter-Premise）
找不到表示词时怎么办（Recognizing Conclusions Without Indicators）
最简单的方法就是把自己认为是原因的句子前加上because，然后验证是否正确。
真实vs. 合理性（Truth versus Validity）
When we evaluate LSAT arguments, we are primarily concerned with validity.
That is, what is the logical relationship of the pieces of the argument and how
well do the premises, if accepted, prove the conclusion? We are less concerned
with the absolute, real world truthfulness of either the premises or the
conclusion.
In a sense this could be called relative
truthfulness—you are only concerned about whether the conclusion is true
relative to the premises, not whether the conclusion is true in an absolute, real
world sense. This is obviously a critical point, and one we will analyze later as
we discuss different question types.
论证的分析（Argument Analysis）
Primary Objective #3: If the stimulus contains an argument,
determine whether the argument is strong or weak.
目标3：如果条件包括一个论证，要分析是否这个论证有力或薄弱
Inferences and Assumptions 推论与假定
Separating an inference from an assumption can be difficult because the
definition of each refers to what “must be true.” The difference is simple: an
inference is what follows from an argument (in other words, a conclusion)
whereas an assumption is what is taken for granted while making an argument.
In one sense, an assumption occurs “before” the argument, that is, while the
argument is being made. An inference is made “after” the argument is
complete, and follows from the argument. Both concepts will be discussed in
more detail in later chapters, but for the time being you should note that all
authors make assumptions when creating their arguments, and all arguments
have inferences that can be derived from the argument.
Read the fine print
One of the purposes of the LSAT is to test how closely you read. This is
obviously an important skill for lawyers (who wants a lawyer who makes a
critical mistake on a big contract?).
Primary Objective #4: Read closely and know precisely what
the author said. Do not generalize!
Scope
范围是逻辑里一个很重要的话题。在广泛的范围内可以推论广泛的东西。在限制的范围内就不要考虑到没有提到的因素。
Notating Argument
注释出论述，根据个人喜好。
总是学不进去的第二章终于被我学完了（5小时）。学习笔记还是有效果的，如果有童鞋有类似的情况不妨也试试。书写的非常好。但感觉考前是看不完了。。。
--------------------------------------------------------------------------------------------------------------------------
Chapter Three: The Question Stem and Answer Choices the Question Stem
本章是一个对13种问题的概述。之后（4-16章是再讲这13种问题的类型）
Analyzing the Question Stem
Primary Objective #5: Carefully read and identify the question stem. Do not assume that certain words are automatically
associated with certain question types.
The Thirteen Logical Reasoning Question Types
Each question stem that appears in the Logical Reasoning section of the LSAT can be classified into one of thirteen different types:
(第4章) Must Be True/Most Supported
(第5章) Main Point
(第6章) Conditional Reasoning
(第7章) Weaken
(第8章) Cause and Effect Reasoning
(第9章) Strengthen, Justify, and Assumption
(第10章) Resolve the Paradox Questions
(第11章) 这章被切了！？
(第12章) Method of Reasoning Questions
(第13章) Flaw in the Reasoning Questions
(第14章) Parallel Reasoning Questions
(第15章) Numbers and Percentages
(第16章) Evaluate the Argument
(第17章) Cannot Be True
(第18章) Point at Issue
(第19章) Principle Question
(第20章) Section Strategy and Management
1. Must Be True/Most Supported
This category is simply known as “Must Be True.” Must Be True
questions ask you to identify the answer choice that is best proven by
the information in the stimulus. Question stem examples:
“If the statements above are true, which one of the following must also
be true?”
“Which one of the following can be properly inferred from the
passage?”
2. Main Point
Main Point questions are a variant of Must Be True questions. As you
might expect, a Main Point question asks you to find the primary
conclusion made by the author. Question stem example:
“The main point of the argument is that”
3. Point at Issue
Point at Issue questions require you to identify a point of contention
between two speakers, and thus these questions appear almost
exclusively with two-speaker stimuli. Question stem example:
“Larew and Mendota disagree about whether”
4. Assumption
These questions ask you to identify an assumption of the author’s
argument. Question stem example:
“Which one of the following is an assumption required by the
argument above?”
5. Justify the Conclusion
Justify the Conclusion questions ask you to supply a piece of
information that, when added to the premises, proves the conclusion.
Question stem example:
“Which one of the following, if assumed, allows the conclusion above
to be properly drawn?”
6. Strengthen/Support
These questions ask you to select the answer choice that provides
support for the author’s argument or strengthens it in some way.
Question stem examples:
“Which one of the following, if true, most strengthens the argument?”
“Which one of the following, if true, most strongly supports the
statement above?”
7. Resolve the Paradox
Every Resolve the Paradox stimulus contains a discrepancy or seeming
contradiction. You must find the answer choice that best resolves the
situation. Question stem example:
“Which one of the following, if true, would most effectively resolve
the apparent paradox above?”
8. Weaken
Weaken questions ask you to attack or undermine the author’s
argument. Question stem example:
“Which one of the following, if true, most seriously weakens the
argument?”
9. Method of Reasoning
Method of Reasoning questions ask you to describe, in abstract terms,
the way in which the author made his or her argument. Question stem
example:
“Which one of the following describes the technique of reasoning used
above?”
10. Flaw in the Reasoning
Flaw in the Reasoning questions ask you to describe, in abstract terms,
the error of reasoning committed by the author. Question stem
example:
“The reasoning in the astronomer’s argument is flawed because this
argument”
11. Parallel Reasoning
Parallel Reasoning questions ask you to identify the answer choice that
contains reasoning most similar in structure to the reasoning presented
in the stimulus. Question stem example:
“Which one of the following arguments is most similar in its pattern of
reasoning to the argument above?”
12. Evaluate the Argument
With Evaluate the Argument questions you must decide which answer
choice will allow you to determine the logical validity of the argument.
Question stem example:
“The answer to which one of the following questions would contribute
most to an evaluation of the argument?”
13. Cannot Be True
Cannot Be True questions ask you to identify the answer choice that
cannot be true or is most weakened based on the information in the
stimulus. Question stem example:
“If the statements above are true, which one of the following
CANNOT be true?”
“Most” in Question Stems
很多题目都有most，如most weaken。这时就要选程度最深的。
1. Must Be True/Most Supported
2. Main Point
3. Point at Issue
4. Assumption
5. Justify the Conclusion
6. Strengthen/Support
7. Resolve the Paradox
8. Weaken
9. Method of Reasoning
10. Flaw in the Reasoning
11. Parallel Reasoning
12. Evaluate the Argument
13. Cannot Be True
“Except” and “Least” in Question Stems P53
表否定，要注意。
Prephrasing Answers P58 非常重要
Most students tend to simply read the question stem and then move on to the
answer choices without further thought. This is disadvantageous because these
students run a greater risk of being tempted by the expertly constructed
incorrect answer choices. One of the most effective techniques for quickly
finding correct answer choices and avoiding incorrect answer choices is
prephrasing. Prephrasing an answer involves quickly speculating on what you
expect the correct answer will be based on the information in the stimulus.
Although every answer you prephrase may not be correct, there is great value
in considering for a moment what elements could appear in the correct answer
choice. Students who regularly prephrase find that they are more readily able
to eliminate incorrect answer choices, and of course, many times their
prephrased answer is correct. And, as we will see in later chapters, there are
certain stimulus and question stem combinations on the LSAT that yield
predictable answers, making prephrasing even more valuable. In part,
prephrasing puts you in an attacking mindset: if you look ahead and
considering a possible answer choice, you are forced to involve yourself in the
problem. This process helps keep you alert and in touch with the elements of
the problem.
Primary Objective #6: Prephrase: after reading the question
stem, take a moment to mentally formulate your answer to the
question stem.
Keep in mind that prephrasing is directly related to attacking the stimulus;
typically, students who closely analyze the stimulus well can more easily
prephrase an answer.
https://www.powerscore.com/lsat/help/lr_prephrasing.cfm
Primary Objective #7: Always read each of the five answer
choices.
Primary Objective #8: Separate the answer choices into
Contenders and Losers. After completing this process, review
the contenders and decide which answer is the correct one.
Primary Objective #9: If all five answer choices appear to be
Losers, return to the stimulus and re-evaluate the argument.
Tricks of the Trade P63 心理测验学
As part of this process, the makers of the LSAT carefully
analyze reams of data from every test administration in order to assess the
tendencies of test takers. As Sherlock Holmes observed, “You can, for
example, never foretell what any one man will do, but you can say with
precision what an average number will be up to.”
以上是第3章，看了这么多终于可以进入实战了。明天目标第4.5章。
感觉自己之所以逻辑差，很有可能是不注意细节。而且考试时浪费时间最多的也是逻辑。
相反，如果可以成功杀逻辑，那么能力会有很大提高。 一切的努力都是值得的。
--------------------------------
(第4章) Must Be True/Most Supported P66
(第5章) Main Point
(第6章) Conditional Reasoning
(第7章) Weaken
(第8章) Cause and Effect Reasoning
(第9章) Strengthen, Justify, and Assumption
(第10章) Resolve the Paradox Questions
(第11章) 这章被切了！？
(第12章) Method of Reasoning Questions P322
(第13章) Flaw in the Reasoning Questions P350---超级重要的一章，做题时经常看不出来为什么错(第14章) Parallel Reasoning Questions P380
(第15章) Numbers and Percentages
(第16章) Evaluate the Argument
(第17章) Cannot Be True
(第18章) Point at Issue
(第19章) Principle Question
(第20章) Section Strategy and Management
------------------------------------------------------------
(第12章) Method of Reasoning Questions P322 论证方法类型题
Prephrasing in Method of Reasoning Questions
Method of Reasoning questions are challenging because they involve abstract
thinking, which focuses on the form of the argument instead of the concrete
facts of the argument. The answer choices will therefore describe the argument
in abstract terms, and many students have difficulty because the test makers are
experts at manipulating those terms to describe the argument in unexpected and
deceptive ways. Often, students will have a firm grasp of the structure of the
argument only to struggle when none of the answers match their prephrase.
This situation occurs because the test makers can use one or two words to
describe entire sections of the stimulus, and you are rigorously tested on your
knowledge of the mechanics of the argument and your ability to discern the
references in the answer choice.
When prephrasing in Method of Reasoning questions, you may understand the
details of the stimulus but not understand the structure of the argument. Thus,
each answer may sound implausible since they are related primarily to the
logical organization of the argument. Therefore, you must think about the
structure of the argument before examining the answer choices. However, do
not expect to see your exact prephrase as the answer; there are simply too many
variations on the way an argument can be described. Instead, make a general,
abstract prephrase of what occurred in the argument and then rigorously
examine each answer choice to see if the test makers have created an answer
that paraphrases your prephrase. Many students are deceived by the description
used by the test makers, and the only way to overcome this problem is to
compare the description given in the answer choice to the stimulus.
Idea Application: Correct and Incorrect Answers Analyzed P326
In this section we present and analyze two Logical Reasoning questions drawn
from real LSATs. We will use the two examples to discuss the various answer
types presented in the previous section and to discuss the language used by the
test makers in the answer choices.
Please take a moment to complete the following problem:
Thirteen: Flaw in the Reasoning Questions
第13章：推论中存在的瑕疵
其实flaw in the reasoning question 与12章的Method of Reasoning Questions推论的方法，在答题时有异曲同工之效。
The Value of Knowing Common Errors of Reasoning
知道一般错误的重要性。
1. Identifying errors of reasoning made in the stimulus
If you learn the mistakes that are often made by authors, then you will
be able to quickly identify the error in the argument and accelerate
through the answer choices to find the correct answer. Students without
this knowledge will be forced to work more slowly and with less
confidence.
熟悉错误类型，让你还没看选项就能猜出来。
2. Identifying answer choices that describe a common error of reasoning
In Flaw in the Reasoning questions, the test makers tend to use certain
types of answers again and again. Depending on the reasoning used in
the stimulus, these answers can describe the correct answer, but more
often than not they are used as “stock” wrong answers. Familiarizing
yourself with these answer choices will give you an advantage when
you encounter similar answer choices in the future. For example,
“attacking the source of an argument, not the argument itself” has
appeared as the correct answer in several LSAT questions. But, it has
appeared in many more questions as a wrong answer choice. If you are
familiar with a “source” argument, you can then make an immediate
determination as to whether that answer is correct or incorrect.
Given the immense advantage you get by knowing the flawed reasoning that
appear most frequently on the LSAT, the following section will detail a variety
of errors of reasoning and provide examples of actual LSAT answer choices
that describe the error under discussion. We strongly recommend that you spend
a considerable amount of time learning these forms of flawed argumentation. It
will definitely help you on the LSAT!
作者苦口婆心地告诉我们多看看错题类型是非常有优势的。战场上，了解敌方的战略是
攻城夺地的重要手段。本章呢就是就是教你这些敌方战略。诸葛亮就在这了，学不学随你。
P352-380
Common Errors of Reasoning Explained 解释一下几种非常普遍的逻辑推论错误。
The following classic errors of reasoning appear with some frequency. The
review is given in layman’s, not philosophical, terms:
类型1；Uncertain Use of a Term or Concept /一个词或概念的不确定的使用。
例题
“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有义务的 only to their
shareholders, and as such they can only assess objects based on their
value.”
注意这道题错的地方时2个value有2个意思，会引起歧义的。
类型2：Source Argument /论述源
Also known as an ad hominem, 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. Here is an example:
“The anti-smoking views expressed by Senator Smith should be
ignored. After all, Smith himself is a smoker!”
本来应该攻击论述内容，结果变成攻击论述的人了。也叫做ad hominem.
1. Focusing on the motives of the source.
2. Focusing on the actions of the source (as in the above example).
类型3：Circular Reasoning 循环式论述
In circular reasoning the author assumes as true what is supposed to be proved.
Consider the following example:
“This essay is the best because it is better than all the others.”
In this example the premise and the conclusion are identical in meaning. As we
know, the conclusion should always follow from the premise. In the example
above, the premise supports the conclusion, but the conclusion equally supports
the premise, creating a “circular” situation where you can move from premise to
conclusion, and then back again to the premise, and so on. Here is another
example: “I must be telling the truth because I’m not lying.”--让我想起了匹诺曹
Here are examples of how this error of reasoning is described in LSAT answer
choices:这里超级重要，因为一般答题看到下面的选项我心里都是崩溃的
“it assumes what it seeks to establish” 它假设了一个它需要建立的理论上
“argues circularly by assuming the conclusion is true in stating the
premises” 把前提建立在结论上。
“presupposes the truth of what it sets out to prove”
提前建立真理与需要被论证的地方
“the argument assumes what it is attempting to demonstrate”
这个论证的假设是它要试着证明的。
“it takes for granted the very claim that it sets out to establish”
声明是要建立的
“it offers, in place of support for its conclusion, a mere restatement of
that conclusion”
论据只是结论的换一种说法而已。
类型4：Errors of Conditional Reasoning 条件论证的错误。
In Chapter Six we discussed several mistakes LSAT authors make when using conditional reasoning, including Mistaken Negation and Mistaken Reversal.
While you should now be comfortable recognizing those errors, Flaw in the Reasoning questions will ask you to describe those mistakes in logical terms.
This often proves to be a more difficult task. 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. As such, here are examples of how these errors of reasoning are described in LSAT answer choices:
“taking the nonexistence of something as evidence that a necessary precondition for that thing also did not exist” (Mistaken Negation)
“mistakes being sufficient to justify punishment for being required to justify it” (Mistaken Reversal)
Note that the authors can either mistake a necessary condition for a sufficient condition, or mistake a sufficient condition for a necessary condition:
Confuses a necessary condition for a sufficient condition
“it treats something that is necessary for bringing about a state of affairs as something that is sufficient to bring about a state of affairs”
“from the assertion that something is necessary to a moral order, the argument concludes that that thing is sufficient for an element of the
moral order to be realized”
Confuses a sufficient condition for a necessary condition
“confuses a sufficient condition with a required condition”
It is interesting to note the frequency with which the words “sufficient” (or its
synonym “assured”) or “necessary” (or its synonym “required”) are used when
analyzing the answer choices used to describe conditional reasoning. This
occurs because those words perfectly capture the idea and it is difficult to avoid
using at least one of those words when describing conditionality. This is a huge
advantage for you: 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.
类型5：Mistaken Cause and Effect
As discussed in Chapter Eight, arguments that draw causal conclusions are
inherently flawed because there may be another explanation for the stated
relationship. Because of the extreme causal assumption made by LSAT authors
(that there is only one cause), any of the following answer choice forms could
be used to describe an error of causality. Underneath each item are examples of
how the error of reasoning is described in LSAT answer choices.
1. Assuming a causal relationship on the basis of the sequence of events.
“mistakes the observation that one thing happens after another for proof
that the second thing is the result of the first”
“mistakes a temporal relationship for a causal relationship”
2. Assuming a causal relationship when only a correlation exists.
“confusing the coincidence of two events with a causal relation between
the two”
“assumes a causal relationship where only a correlation has been
indicated”
3. Failure to consider an alternate cause for the effect, or an alternate cause
for both the cause and the effect.
“fails to exclude an alternative explanation for the observed effect”
“overlooks the possibility that the same thing may causally contribute
both to education and to good health”
4. Failure to consider that the events may be reversed.
“the author mistakes an effect for a cause”
Note the frequency with which the words “cause” or “effect” are used. This
occurs because there are few substitutes for those two words, and thus the test
makers are often forced to use those words to describe an argument containing
causality. If you identify a stimulus with causal reasoning and are asked a Flaw
question, quickly scan the answers for one that contains “cause,” “effect,” or
both.
类型6：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. In
figurative terms, a “straw” argument is built up which is then easier for the
author to knock down.
Often this error is accompanied by the phrase “what you’re saying is” or “if I
understand you correctly,” which are used to preface the refashioned and
weakened argument. Here is an example:
Politician A: “The platform proposed by my party calls for a moderate
increase in taxes on those individuals making over $20,000
per year, and then taking that money and using it to rebuild
the educational system.”
Politician B: “But what you’re saying is that everyone should pay higher
taxes, and so your proposal is unfair.”
In the example above, Politician B recasts Politician A’s argument unfairly.
Politician A indicated the tax increase would apply to those with incomes over
$20,000 where Politician B distorts that to “everyone should pay higher taxes.”
Here are examples of how this error of reasoning is described in LSAT answer
choices:
“refutes a distorted version of an opposing position”
“misdescribing the student representative’s position, thereby making it
easier to challenge”
“portrays opponents’ views as more extreme than they really are”
“distorts the proposal advocated by opponents”
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. Here is an example:
“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.”
The author provides irrelevant evidence in an attempt to refute the claim that
“scientific progress has increased the polarization of society and alienated large
segments of the population.” Citing facts that such a situation has always existed
does not help disprove that scientific progress has increased the severity of the
situation.
Here are examples of how this error of reasoning is described in LSAT answer
choices:
“The author cites irrelevant data.”
“draws a conclusion that is broader in scope than is warranted by the
evidence advanced”
“It uses irrelevant facts to justify a claim about the quality of the
disputed product.”
“It fails to give any reason for the judgment it reaches.”
“It introduces information unrelated to its conclusion as evidence in
support of that conclusion.”
“Everyone should join our country club. After all, it’s an exclusive
group that links many of the influential members of the community.”
The self-contradiction occurs when the speaker says “Everyone should join”
and then follows that by saying that it is “an exclusive group.” Exclusive, by
definition, means that some people are excluded.
The following show how this error of reasoning is described in LSAT answer
choices:
“bases a conclusion on claims that are inconsistent with each other”
“the author makes incompatible assumptions”
“introduce information that actually contradicts the conclusion”
“offers in support of its conclusion pieces of evidence that are mutually
contradictory”
“some of the evidence presented in support of the conclusion is
inconsistent with other evidence provided”
“assumes something that it later denies, resulting in a contradiction”
Appeal Fallacies
While there are a number of “appeal” fallacies that appear in traditional logic
(Appeal to Fear, Appeal to Force, Appeal to Tradition, etc.), the following three
are the most applicable to the LSAT:
1. 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. Here is an example:
“World-renowned neurologist Dr. Samuel Langhorne says that
EZBrite Tooth Strips are the best for whitening your teeth. So,
you know if you buy EZBrite you will soon have the whitest
teeth possible!”
The primary defect in this argument is its use of a neurologist as an
authority figure in an area of dentistry. While Dr. Langhorne can
reasonably be appealed to in matters of the brain, dental care would be
considered outside the scope of his expertise.
Here are examples of how this error of reasoning is described in LSAT
answer choices:
“the judgement of experts is applied to a matter in which their
expertise is irrelevant”
“the argument inappropriately appeals to the authority of the
mayor”
“it relies on the judgment of experts in a matter to which their
expertise is irrelevant”
“accepts a claim on mere authority, without requiring sufficient
justification”
2. Appeal to Popular Opinion/Appeal to Numbers
This error states that a position is true because the majority believes it to
be true. As you know, arguments are created by providing premises that
support a conclusion. An appeal to popular opinion does not present a
logical reason for accepting a position, just an appeal based on numbers.
Here is an example:
“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 (with the exception
of utilities), and therefore Microsoft should be controlled or
broken into smaller pieces.”
The author uses the results of a poll that indicate many people think
Microsoft is a monopoly to conclude that Microsoft is in fact a
monopoly. This type of persuasion is often used in the arguments made
by advertisements (“All the trend setters use EZBrite Tooth Strips”),
politicians (“Everyone loves the environment. Vote for the Green
Party!), and children (“C’mon, try this. Everyone does it.”).
This type of reasoning most often appears as an incorrect answer. Here
are examples of how this error of reasoning is described in LSAT
answer choices:
“it treats popular opinion as if it constituted conclusive evidence
for a claim”
“attempts to discredit legislation by appealing to public
sentiment”
“a claim is inferred to be false merely because a majority of
people believe it to be false”
“the argument, instead of providing adequate reasons in support
of its conclusion, makes an appeal to popular opinion”
3. Appeal to Emotion
An Appeal to Emotion occurs when emotions or emotionally-charged
language is used in an attempt to persuade the reader. Here is an
example:
“Officer, please do not give me a ticket for speeding. In the last
month I’ve been fired from my job, kicked out of my apartment,
and my car broke down. I don’t deserve this!
Here are examples of how this error of reasoning is described in LSAT
answer choices:
“attempts to persuade by making an emotional appeal”
“uses emotive language in labeling the proposals”
“the argument appeals to emotion rather than reason”
Survey Errors
The makers of the LSAT believe that surveys, when conducted properly,
produce reliable results. However, surveys can be invalidated when either of the
following three scenarios arise:
1. The survey uses a biased sample.
Perhaps the most famous example of a biased survey occurred in 1936.
The Literary Digest weekly magazine sent out ballots to some 10
million voters (2.3 million were returned), and returns indicated that a
solid majority would vote for Republican candidate Alf Landon in the
upcoming presidential election. On the basis of these results (and the
size of the sample), the Literary Digest predicted that Landon would
win easily. Of course, when the election was held Franklin Roosevelt
won in a landslide. The Literary Digest erred by sending the ballots to
groups such as telephone owners and automobile owners, groups that in
that era (late Depression) tended to be among the wealthiest individuals
and overwhelmingly Republican. The Literary Digest ended up polling
a large number of Republicans and on that basis declared that the
Republican candidate would win.
Note that a secondary error with the polling done by the Literary Digest
is that the sample is self-selected; that is, the individuals being polled
decided whether or not to respond. That opportunity introduces bias into
the survey process because certain types of individuals tend to respond
to surveys whereas others do not.
2. The survey questions are improperly constructed.
If a survey question is confusing or misleading, the results of the poll
can be inaccurate.
Questions can be confusing, such as “Do you feel it is possible that
none of the candidates would not vote to increase taxes?” (The question
actually asks, “Do you feel it is possible that all of the candidates would
vote to increase taxes?”). If a respondent cannot understand the
question, how can they accurately answer the question?
Questions can also be misleading, such as “How soon should the U.S.
government withdraw from the United Nations?” The question
presumes that the United States should withdraw from the United
Nations—a course of action that the respondent may not agree with.
3. Respondents to the survey give inaccurate responses.
People do not always tell the truth when responding to surveys. Two
classic questions that often elicit false answers are “What is your age”
and “how much money do you make each year?”
If respondents give false answers to survey questions, the results of the
survey are skewed and inaccurate.
Here are examples of how the errors of reasoning above are described in LSAT
answer choices:
“uses evidence drawn from a small sample that may well be
unrepresentative”
“generalizes from an unrepresentative sample”
“states a generalization based on a selection that is not representative of
the group about which the generalization is supposed to hold true”
Exceptional Case/Overgeneralization
This error takes a small number of instances and treats those instances as if they
support a broad, sweeping conclusion. Here is an example:
“Two of my friends were shortchanged at that store. Therefore,
everyone gets shortchanged at that store. ”
This answer appears most frequently as an incorrect answer in Flaw questions,
but as with any of the errors described in this chapter, occasionally it appears as
a correct answer. Here are examples of how this error of reasoning is described
in LSAT answer choices:
“supports a universal claim on the basis of a single example”
“The argument generalizes from too small a sample of cases”
“Too general a conclusion is made about investing on the basis of a
single experiment”
“bases a general claim on a few exceptional instances”
Errors of Composition and Division
Composition and division errors involve judgments made about groups and
parts of a group.
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. Here
is an example:
“Every party I attend is fun and exciting. Therefore, my life is fun and
exciting.”
Here are examples of how this error of reasoning is described in LSAT answer
choices:
“assuming that because something is true of each of the parts of a whole
it is true of the whole itself”
“improperly infers that each and every scientist has a certain
characteristic from the premise that most scientists have that
characteristic”
“takes the view of one lawyer to represent the views of all lawyers”
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. Here is an
example:
“The United States is the wealthiest country in the world. Thus, every
American is wealthy.”
Here is an example of how this error of reasoning is described in LSAT answer
choices:
“presumes, without providing justification, that what is true of a whole
must also be true of its constituent parts”
False Analogy
As discussed in the answer key to the problem set in the previous chapter, an
analogy is a comparison between two items. A False Analogy occurs when the
author uses an analogy that too dissimilar to the original situation to be
applicable. Here is an example:
“Just as a heavy rainfall can be cleansing, the best approach to maintain
a healthy relationship is to store up all your petty grievances and then
unload them all at one time on your partner.”
The comparison in the example fails to consider that a heavy rainfall and an
emotionally charged situation are fundamentally different.
Here are two examples of how a False analogy is described in LSAT 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 do
not differ”
False Dilemma
A False Dilemma assumes that only two courses of action are available when
there may be others. Here is an example:
“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.”
The argument above falsely assumes that only two courses of action exist:
industry self-policing or government action. But this ignores other courses of
action, such as consumer watchdog groups.
Do not confuse a False Dilemma with a situation where the author legitimately
establishes that only two possibilities exist. Phrases such as “either A or B will
occur, but not both” can establish a limited set of possibilities, and certain realworld
situations yield only two possibilities, such as “you are either dead or
alive.”
Here is an example of how a False Dilemma is described in LSAT answer
choices:
“fails to consider that some students may be neither fascinated by nor
completely indifferent to the subject being taught”
Errors in the Use of Evidence
Mis-assessing the force of evidence is a frequent error committed by LSAT
authors. Each of the following describes an error of reasoning involving the
force of evidence:
1. Lack of evidence for a position is taken to prove that position is false.
Just because no evidence proving a position has been introduced does
not mean that the position is false. Here is an example:
“The White House has failed to offer any evidence that they
have reached a trade agreement with China. Therefore, no such
agreement has been reached.”
In the example above the White House may have valid reasons for
withholding information about the trade agreement. The lack of
confirming evidence does not undeniably prove that a trade agreement
has not been reached.
Here are two examples of how this error of reasoning is described in
LSAT answer choices:
“treats failure to prove a claim as constituting denial of that
claim”
“taking a lack of evidence for a claim as evidence undermining
that claim”
2. Lack of evidence against a position is taken to prove that position is
true.
This error is the opposite of the previous error. Just because no evidence
disproving a position has been introduced does not mean that the
position is true. Here is a famous example:
“There has been no evidence given against the existence of God,
so God must exist.”
The lack of evidence against a position does not undeniably prove a
position. Here is an example of how this error of reasoning is described
in LSAT answer choices:
“treating the failure to establish that a certain claim is false as
equivalent to a demonstration that the claim is true”
3. Some evidence against a position is taken to prove that position is false.
The introduction of evidence against a position only weakens the
position; it does not necessarily prove the position false. Here is an
example:
“Some historians claim that a lengthy drought preceded the fall
of the Aztec empire. But we know from Aztec writings 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 offered in the example above weakens the claim that there
was a lengthy drought, but it does not disprove it. A drought by
definition is a prolonged period of unusually low rainfall, and thus it
would be possible for flooding to occur on occasion, but not enough
flooding to overcome the general drought conditions.
Here is an example of how this error of reasoning is described in an
LSAT answer choice:
“it confuses undermining an argument in support of a given
conclusion with showing that the conclusion itself is false”
4. Some evidence for a position is taken to prove that position is true.
The introduction of evidence for a position only provides support for the
position; it does not prove the position to be undeniably true. Here is an
example:
“We know that the defendant was in the vicinity of the robbery
when the robbery occurred. Therefore, the defendant is guilty of
the robbery.”
As the above example proves, partial support for a position does not
make the position invincible (especially in LSAT arguments, which are
relatively short). As you might expect, partial evidence for a position can
be outweighed by evidence against that position.
Here is an example of how this error of reasoning is described in an
LSAT answer choice:
“the argument takes evidence showing merely that its conclusion
could be true to constitute evidence showing that the conclusion
is in fact true”
Time Shift Errors
Although this error has a rather futuristic name, 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.
“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.”
Clearly, what has occurred in the past is no guarantee that the future will be the
same. Yet, many LSAT authors make this assumption, especially when
hundreds or thousands of years are involved. Here are examples of how this
error of reasoning is described in LSAT answer choices:
“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”
“uncritically draws an inference from what has been true in the past to
what will be true in the future”
Numbers and Percentage Errors
In Chapter Fifteen we will discuss numbers and percentages problems in detail.
Meanwhile, consider that many errors in this category are committed when an
author improperly equates a percentage with a definite quantity, or when an
author uses quantity information to make a judgment about the percentage
represented by that quantity.
Here is an example of how this error of reasoning is described in an LSAT
answer choice:
“the argument confuses the percentage of the budget spent on a program
with the overall amount spent on that program”
----------------------------------------------------------------------------------------
(第14章) Parallel Reasoning Questions 平行推论问题 P380
(第15章) Numbers and Percentages
(第16章) Evaluate the Argument
(第17章) Cannot Be True
(第18章) Point at Issue
(第19章) Principle Question
(第20章) Section Strategy and Management
----------------------------------------------------------------------------------------
最近各种找工作，导致心上长草。还有世故人情，人间百态。反正一读逻辑什么都可以想到，上到天文下到地理。
分分钟能给你讲个评书。我这个思想不集中的病还能医吗。
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发表于 2017-2-4 19:40:07
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