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LSAT Notes.
LSAT Logical Reasoning Premises and Conclusions | Indicators I. Premise Indicators - Because - Since - For - For Example - For the Reason That - In That II. -
Conclusion Indicators Thus
Therefore Hence Consequently As a Result So Accordingly
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Given That
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Clearly
As Indicated By Due To Owing To This Can Be Seen From We Know This By
Must Be That Shows That Conclude That Follows That For This Reason
NOTES - Premises and conclusions can be constructed without any indicator words present
- A fact set does not contain a conclusion; an argument must contain a conclusion
- Additional premise indicators includes: furthermore, moreover, besides, in addition, what’s
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more
• can be central to argument or secondary
• determine importance of these indicators by evaluating entire argument
Counter-premise indicators bring up points of opposition or comparison. Examples of these include: but, yet, however, on the other hand, ittedly, in contrast, although, even though, still, whereas, in spite of, despite, after all
Look for validity (versus truth) in LSAT arguments
If the stimulus contains an argument, determine whether the argument is strong or weak.
LSAT authors do not tend to deceive you; assume that any argument posed by the argument is believed 100%; the test producers are the ones that intend to deceive.
Always read closely and know precisely what the author said. Do not generalize.
Make sure everything is within the scope of the argument.
On average, 1 minute and 25 seconds for each questions
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Read carefully and identify the question stem Do not assume that certain words are automatically assumed with certain question types.
Question Types I. Must Be True/Most ed
A. Identify the answer choice that is best proven from the information in the stimulus
II. Main Point
A. Find the primary conclusion made by the authors
III. Point at Issue
A. Identify a point of contention between 2 speakers
IV. Assumption
A. Identify what author must assume in order for the argument to be valid
V. Justify the Conclusion
A. Supply a piece of information that, when added to the premises, proves the conclusion.
VI. Strength/
A. Select the answer choice that provides the most for the author’s argument or strengthens it in some way.
VII. Resolve the Paradox
A. Stimulus contains a discrepancy or seeming contradiction. Find the answer choice that resolves this situation
VIII.Weaken
A. Attack or undermine the author’s argument
IX. Method of Reasoning
A. Describe, in abstract , the way in which the author made their argument.
X. Flaw in the Reasoning
A. Describe, in abstract , the error of reasoning committed by the author
XI. Parallel Reasoning
A. Identify the answer choice that contains reasoning most similar in structure to the reasoning presented in the stimulus. XII.Evaluate the Argument A. Decide which answer choice allows you to determine the logical validity of the argument XIII.Cannot Be True
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A. Identify answer choice that cannot be true or is most weakened based on the information from the stimulus.
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Last Update: Sunday, December 1, 2013
LSAT Notes.
Question Types: Keys and Explained. I. Main Point Questions: Conclusion of argument is the main point. Avoid answers that may be true but don’t contain the main point or that repeat the premise of argument.
II. Must Be True: Use fact test—reference the stimulus to prove correct answer. Keep within the scope of the argument. Look for answers that combine 2+ phrases from stimulus.
III. Conditional/Formal Logic: Sufficient—-> Necessary. Contrapositive: flip the order and negate.
- Conditional Linkage: If A->B and C->A; then C->A->B or rather C->B
- Either/Or: At least one and maybe both need to be present.
- Multiple Conditions: In order to NECESSARY you must be SUFFICIENT 1 and SUFFICIENT 2; Contrapositive-If you are not SUFFICIENT 1 or SUFFICIENT 2, then you will not NECESSARY.
- Bi-Conditionals: If and only if; Either both are present or neither are present.
- Double Not Arrow: If one is present, the other cannot be.
IV. Weaken: Look for answer choice that weakens the conclusion of the argument
- Conclusion doesn’t follow premise
- Author’s assumptions
- Error of assumption
- How did the author arrive at his/her conclusion?
• Incomplete info can be weakened with new info
• Qualified conclusion—may limit the conclusion “all” “none”
• Improper comparison—2 items being compared are very different.
A. Always attack the necessary condition
V. Causal Conclusions: Always look for the assumption
VI. Strengthen: the argument (ie: the conclusion) in any way to any degree.
VII.Justify the Conclusion: Strengthen so that the conclusion is 100% proven.
- Premises + correct answer choice = the conclusion
- An answer with a new element in the conclusion will be incorrect
- If element is in premise and conclusion and answer choice, then skip it—it will probably be incorrect.
- An answer with new elements that are in premises but not conclusions
VIII.Assumption: This is the unstated premise that the argument relies on.
- er: Connects rouge pieces/info
- Defender: protects argument from ideas that could weaken conclusion.
- Assumption Negation Technique
• Logically Negate Answer Choice
• Negated answer choice will attack and weaken argument if correct answer
- Quirks to look for:
• “At lease one/some”
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Avoid answers that claim something was author’s “top priority” or “main purposes”
• Watch for “not” or negatives in A.C.
Formal Logic - This is the study of the properties of propositions and deductive reasoning by abstraction and -
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analysis of the form rather than the content of the propositions under consideration.
Standard way of translating relationships into symbols and then making inferences from those symbolized relations.
Basis for Formal Logic are such as all, none some and most Every Formal Logic Relationship features at least 2 separate variables linked in a relationship
• Variables represent groups of ideas
Diagraming Formal Logic Questions
• Choose symbols to represent each variable.
• Use conditional reasoning and diagrams (arrows)
- The Single Arrow (—>) Introduced by sufficient and necessary words/conditions. Sufficient on the left, necessary on the right. Contrapositive, flip the order and negate.
- The Double Arrow (<—>) Introduced by “if and only if ” or by situations where the author implies that the arrow goes both ways by adding like “vice versa”
• Either both variables occur or both don’t
- The Double Not Arrow (<—/—>) Introduced by conditional statements where exactly one of the is negative or by statements using words such as “no” and “none” that imply that the two variables cannot go together.
• Either Term 1, Term 2, or (in some instances) neither.
The Concept of Some
• Defined as “at least one, possibly all”
• Some are not—could mean “none”
• Ways to say “some” on the LSAT - Some
- A few
- Part of
- At least some
- A number
- A portion
- At least one
- Several
The Concept of Most
• Defined as “a majority, possibly all”
• Most are not—could mean none
• Ways to say “most” on the LSAT - Most
- More than half
- Usually
- A majority
- Almost all
- Typically There is not a contrapositive for most or some statements
Formal Logic Numerically • All= 100
• Some Are Not & Not All= 0 to 99
• Most= 51 to 100 (“a majority)
• Most Are Not= 0 to 49
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LSAT Notes. • Some= 1 to 100 (at least one)
• None=0 - All and none are precise.
- The Rules of Reversibility
• The relationship between the 2 variables has exactly the same meaning regardless of which
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“side” of the relationship is the starting point of your analysis
- None, some, some are not and double arrow statements are reversible
- “Some A’s are not B’s”
• Reversal of this is “Some things that are not B are A”
• Statements that are non-reversible have a single “direction” meaning that the relationship between the 2 variables is not the same.
- All and most are non-reversible
Formal Logic Inferences • Additive: result from combining multiple statements through a common term and then deducing a relationship that does not include the common term
• Inherent: follow from a single statement. Know this inference to be true simply from the relationship between the 2 variables.
• The Logic Ladder:
- All [Most (Some)]
• The Negative Logic Ladder:
- None [Most Are Not (Some Are Not)]
Always try to make formal logic additive inferences once you have listed what’s inferred.
• Start by looking at the ends of the chain
• Vast majority of additive inferences require either an all or none statement somewhere in the chain
• 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: look for arrow that “leads away” from the some relationship
- Look for the weakest link in the chain to make inference
- The presence of relevant negativity
• The Most Train: similar to some train, but produces stronger inferences.
• Arrows and double-not arrows almost always elicit additive inferences
• Use inherent inferences
• Watch for the relevant negativity
- Either the first or last rem is negated or
- There is a double-not arrow in the chain
• Some and Most Combinations
- 2 consecutive some’s, most’s or a some and a most in succession will not yield any inferences.
• Analyze compound statements
• Once an inference bridge is built, it does not need to be built again
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Last Update: Sunday, December 1, 2013
LSAT Notes.
Conditional Reasoning - A sufficient condition can be definite as an event or circumstance whose occurrence indicates -
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that a necessary condition must also occur
A necessary condition can be defined as an event or circumstance whose occurrence is required in order for the sufficient condition to occur
Logical Features of Conditional Reasoning
• The sufficient conditional does not make the necessary condition occur. Rather, it is a sign or indicator that the necessary condition will/must occur
• Temporally speaking, either conditional can occur first—or, they can occur at the time time
• The conditional relationship statement by the author does not have to reflect reality
Develop the contrapositive by reversing the and negating. The contrapositive denies the necessary condition, thereby making it impossible for the sufficient condition to occur.
Valid and Invalid Inferences
• Repeat form simply restates the elements in the original order the appeared; valid
• Mistaken reversal (reverses the without negating); invalid
• Mistaken negation (negating both conditions but not reversing ); invalid
Sufficient Condition Indicators • If
• Every
• People Who
• When
• All
• In order to • Whenever
• Any
Necessary Condition Indicators • Then
• Must
• Except
• Only
• Required
• Until
• Only If
• Unless
• Without Unless Equation • Whatever term is modified by unless, except or without becomes the necessary condition
• The remaining term is negated and becomes the sufficient condition
When a stimulus that contains Conditional Reasoning is combined with a Must Be True questions stem, immediately look for the Repeat or Contrapositive in the answer choices.
Always look for the most difficult./longest answer—test makers like to use this as the correct answer (chain inference)
With “and/or” —If “and” is used in sufficient condition, “or” must be used in contrapositive.
Conditional reasoning can occur in many different question types
Cause and Effect Reasoning - Causality occurs when one event is said to make the other one occur. The cause is the event that makes the other occur and the effect is the event that follows from the cause
- Most causal conclusions are flawed because:
• There can be alternate explanations for the stated relationship
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Last Update: Sunday, December 1, 2013
LSAT Notes.
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• • • • •
Some other cause could for the effect
Some third event may have caused both the stated cause and effect
The situation may be reversed
The events may be related, but not causally
The entire occurrence could be by the result of chance.
Conditional Reasoning versus Causal Reasoning
• The chronology of the 2 events can differ.
- For cause and effect, cause must come before the effect. For conditional, order does not matter.
• The connection between the events is different.
- In cause and effect statements, the events are related in a direct way—the cause physically makes the effect happen. In conditional statements, the sufficient and necessary conditions are often related directly, but they do not have to be.
• The language used to introduce the statements is different.
- Words that introduce each type of relationship are very different. Causal indicators are active, powerful words while most conditional indicators do not possess those traits.
Causal statements can be used in the premise or conclusion of an argument.
• If causal statement is the conclusion, the reasoning is flawed.
• If it’s in the premise, the argument may be flawed, but not because of the causal statement.
Scenarios that lead to causal conclusions in LR Questions
• One event occurs before another
• Two or more events occur at the same time
If LSAT speaker concludes that the occurrence caused another, the speaker also assumes that the stated cause is the only possible cause of the effect and agh the stated cause will always produce the effect—FLAW?
In Weaken Questions, attacking a cause and effect relationship almost always consists of performing one of the following tasks:
• Find an alternative cause for the stated effete
• Show that even when the cause occurs, the effect doesn’t
• Show that although the effect occurred the cause did not
• Show that the stated relationship is reversed
• Show a statistical problem exists with the data to make the causal statement
Causal reasoning occurs in many different question types
Numbers and percentages - Words used to introduce numerical ideas: • Amount
• Total
• Sum
• Quantity
- Words used to introduce percentage ideas: • Percent
• Proportion
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• Count
• Tally • Fraction
Last Update: Sunday, December 1, 2013
LSAT Notes. • Ratio
• Incidence
• Likelihood
• Probability
• Segment
• Share
- Misconceptions Regarding Numbers and Percentages:
• Increasing percentages automatically lead to increasing numbers
• Decreasing percentages automatically lead to decreasing numbers
• Increasing numbers automatically lead to increasing percentages
• Decreasing numbers automatically lead to decreasing percentages
• Large numbers automatically mean large percentages and small numbers automatically mean
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small percentages
• Large percentages automatically mean large numbers and small percentages automatically mean small numbers
Use the following rules for Must Be True Questions
• If the stimulus contains percentages of proportion information only, avoid answers that contain hard numbers [Ex: The car market share of Company X declined this year]
- Company X sold a smaller number of cars this year
- Company X sold a greater amount of cars this year
• If the stimulus contains only numerical information, avoid answers that contain percentage or proportion information [Company Y sold fewer computers this year]
- Company Y now has a lower share of the computer market
- Company Y now has a higher share of the computer market
• If the stimulus contains both percentage and numerical information, any answer choice that contains numbers, percentages or both may be true.
Use the following rules for Weaken and Strengthen Questions
• To weaken or strengthen an argument containing numbers and percentages, look carefully for information about the total amounts —does the argument make an assumption based on one of the misconceptions discussed above?
Market Share is simply the portion of a market that a company controls. It ca be measured in either of revenues (sales) or units sold. Regardless of the size of a market, total market share always add up to 100%.. It is a comparative term.
Numerical situation hinge on three elements:
• Overall Total
• A number within the total
• Percentage within the total.
LSAT questions will often give you one of the elements, but without at least two of these elements present, you cannot make a definite judgement about what is occurring with another element.
Knowledge of a percentage is insufficient to allow you to determine anything 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.
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Last Update: Sunday, December 1, 2013
LSAT Notes.
Principle Questions - A principle is a broad rule that specifies what actions or judgements are correct in certain -
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situations
The degree of generality of principles can vary considerably
Presence of principle indicator in a question stem serves to broaden the scope of the question.
Question becomes more abstract and you must analyze the problem identify the underlying relationships
Must Be True Principle Questions
• Must us the principle presented in the stimulus and then apply it to the situation in each answer choice.
• The answer choice can address a scenario not specifically included in the stimulus; therefore, your job is to find the answer that follows from the application of the principle.
Questions are often lengthy; may be the type to skip.
In conditional principle questions, you can conclude:
• If the sufficient condition is met in one of the scenarios in the answer choice, then it can be concluded that the necessary condition occurred.
• If the necessary conditional is not met in one of the scenarios in the answer choices, then it can be concluded that the sufficient condition has not occurred.
• If the sufficient condition is not met in one of the scenarios in the answer choices, you can conclude that the necessary conniption may or may not have occurred.
• If the necessary condition is met in one of the scenarios in the answer choice, you can conclude that the sufficient condition may or may not have occurred.
Correct answer will always feature a scenario that addresses each part of the principle
Strengthen/Justify Principle Questions
• Each answer choice contains a principle that acts as an additional, board premise that s or proves the conclusion.
• Ask—“if this answer is true, does it or prove the conclusion?”
• Do not eliminate an answer because you disagree with the principle in its answer choice
• Correct answer provides a broad premise that can be added to the argument to help prove the conclusion.
When you encounter a Principle Question, prepare to apply the principle to a situation that falls under the purview of the principle but is not necessarily directly addressed by the principle.
First Family: Must Be/Prove Family 1. Must Be True
2. Main Point
3. Point at Issue
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4. Method of Reasoning
5. Flaw in Reasoning
6. Parallel Reasoning
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Take information from the stimulus to & select correct answer choice
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Last Update: Sunday, December 1, 2013
LSAT Notes. Must Be True - Correct answers will either be:
• Paraphrased Answer - These are answers that restate a portion of the stimulus in different .
- Test your ability to discern the author’s exact meaning.
- Can appear to be almost too obvious. Don’t be afraid to pick the easy/obvious choice!
• Answers that are the sum of 2 or more stimulus statements (combination answers) - Any answer choice that would result from combining 2 or more statements in the stimulus will be correct.
- Incorrect answers in must be true questions
• “Could be true” or “likely to be true” answers
- select the answer choice that must occur
• Exaggerated answers
- take information from the stimulus and then stretch that information to make a broader statement that is not ed by the stimulus.
- often paraphrased, but uses like “most,” “none,” “all,” etc.
• “New” Information Answers
- Always be wary of any answer choice that does not directly reference information that was stated in the stimulus.
- Examine the scope of the argument to make sure that information does not fall within the sphere of a term or concept in the stimulus before ruling it out.
- Examine the answer to make sure it’s not a consequence of combining stimulus elements
• The Shell Game
- An idea of concept is raised in the stimulus and then a very similar idea appears in the answer choice, but the idea is changed just enough to be incorrect, yet still attractive.
• Opposite Answer
- Answer is completely opposite of the stated facts of the stimulus.
• Reverse Answer
- Contains familiar elements but presents them in the opposite way they are supposed to be presented. Rearranges elements to create a new, uned statement
- Must be true questions require you to select an answer choice that is proven by the info presented in the stimulus.
- All MBT answer choice must the Fact Test in order to be correct.
• The correct answer to a MBT questions can always be proven by referring to the facts stated in the stimulus
- The scope of the stimulus—especially if that scope is broad—often helps to eliminate one or more of the answer choices
- Stimulus of most MBT questions do not have a conclusion/argument—really just a set of facts.
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Main Point Questions
- Incorrect Main Point Answers
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Answers that are true but do not encapsulate the author’s loin
• Answers that repeat premises of the argument
- The main point is the same as the conclusion of the argument
- Correct answer choice must not only be true according to the stimulus, it must also summarize the author’s point.
- Avoid answers that are true but miss the point of the author’s argument
- Fill in the Bank questions are Main Point questions in disguise
• emphasis of these questions is on using the contextual clues provided in the stimulus to find
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the voice that best fits the blank
Method of Reasoning - Can only use information found in the stimulus to prove the correct answer choice.
- Any answer choice that describes an element or situation that does not occur in the stimulus is incorrect
- These questions are simply abstract Must Be True questions
- Fact Test • If an answer choice describes an event that did not occur in the stimulus, that answer is incorrect.
• Watch out for answers that are partially true.
- Stimulus will contain an argument and the argument can contain either valid or invalid reasoning.
- Must watch for the presence of the premises and conclusion
- Incorrect Answers in Method of Reasoning Questions:
• New Element Answers
• Half Wrong, Half Right Answers
• Exaggerated Answers
• The Opposite Answer
• The Reverse Answer
- Argument Part Questions • Question stem cites a specific part of the stimulus and then asks you to identify the role that the cited portion plays in the structure of the argument
• These tend to be more complex than the average LSAT stimulus
• Often feature 2 conclusions—a main conclusion and a subsidiary conclusion
- The main conclusion is typically placed in the first or second sentence and the last sentence contains the subsidiary conclusion
- Subsidiary conclusion is often preceded by a conclusion indicator such as “thus” or “therefore” while the main conclusion is not prefaced by such indicator
• Avoid answers that may be correct but reference a different part of the question stem.
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Flaw in the Reasoning - Very similar to method of reasoning questions.
- Solve these questions by:
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Identifying errors of reasoning made in the stimulus
• Identifying answer choices that describe a common error of reasoning
Types of Flaws I. Uncertain use of a term or concept.
- Term is not used in a constant, coherent fashion
- Ex: Depending on the ambiguous use of a key term
II. Source argument/ad hominem
- Attacks the person (or source) instead of the argument they advance
- Focusing on the motives of the source
- Focusing on the actions of the source
- Ex: Makes an attack on the character of their opponent
III. Circular Reasoning
- Author assumes as true what is supposed to be proven
- “This essay is the best because it’s better than others”
- Ex: Assumes what it seeks to establish
IV. Errors of Conditional Reasoning
- Taking the nonexistence of something as evidence that a necessary pre-condition for that thing also did not exist
- Mistakes being sufficient to justify something for being necessary
- Confuses necessary condition for a sufficient condition or vice versa
- Mistaken Negation and Mistaken Reversal
V. Mistaken Cause and Effect
- Assuming causal relationship on the basis of the sequence of events (mistakes a temporal relationship for a causal relationship)
- Assuming causal relationship when only a correlation exists (confusing the coincidence of 2 events with a causal relationship between the two.)
- Failure to consider an alternative cause for the effect of the cause and effect (fails to exclude an alternative explanation for the observed effect)
- Failure to consider that the events might be reversed
VI. Straw Man
- Attempt 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 and easier to attack in the process
- Ex: Refutes a distorted version of an opposing position
VII. General Lack of Relevant Evidence for the Conclusion
- Fail to provide any info to their conclusion
VIII.Internal Contradiction
- Authors mistakes conflicting statements
- Ex: “Bases a conclusion on claims that are inconsistent with each other”
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Last Update: Sunday, December 1, 2013
LSAT Notes. IX. Appeal to Authority
- Uses opinion of an authority in an attempt to persuade the reader
- Ex: “judgement of experts is applied to a matter in which their expertise is irrelevant”
X. Appeal to Popular Opinion/Numbers
- States that a position is true because the majority believes it to be true
XI. Appeal to Emotion
- Emotions or emotionally charged language is used as an attempt to persuade the reader
XII.Survey Errors
A. Uses biased sample that is unrepresentative of population to draw a conclusion
B. Improperly constructed questions
1. Survey questions are confusing or misleading
2. Misleading and presumes questions
C. Inaccurate Responses—people do not always tell the truth when responding to surveys
XIII.Exceptional Cause and Overgeneralization
- Takes a small number of instances and treated those instances as though they a broad, sweeping conclusion
XIV.Errors of Composition and Division
- Judgement is made about groups and parts of a group based on a characteristic of part of the group. Author attributes a characteristic of part of the group to the group as a whole or each member
XV. False Analogy
- Author uses analogy that is too dissimilar to the original situation to be accurate
XVI. False Dilemma
- Assumes only two courses of action are available when there may be others
XVII. Errors in the Use of Evidence
A. Lack of evidence for a position is taken to prove that the position is false; treats failure to prove a claim as constitutional denial of that claim.
B. Lack of evidence against a position is taken to prove that that position is true—just because there has not yet been evidence introduced to disprove a position does not mean that the position is true.
C. Evidence against a position is taken to prove that a position is false. Introduction of evidence against a position only weakens the position; it does not necessarily prove the position to be false.
D. Some evidence for a position is taken to prove that the position is true.
XVIII.Time Shift Errors
- Assuming that the conditions will remain constant over time
- Ex: “Treats a claim about what is currently the case as if it were a claim about what will happen for an extended about of time”
XIX.Numbers and Percentage Errors
- Author improperly equates a percentage with a definite quantity
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Or, uses quantity information to make a judgement about the percentage represented by that
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quantity.
Parallel Reasoning
- Identify the answer choice that contains reasoning most similar in structure to the reasoning in the stimulus
- Parallel Flaw questions require that you find an answer choice with the same flawed reasoning
- Evaluate and Solve Parallel Reasoning Questions by examining the following items:
• Method of Reasoning—recognize the form used in stimulus and look for answer choice with the same form.
• Validity of the Argument—Validity of the reasoning in the correct answer choice must match the validity of the reasoning in the stimulus
• The Conclusion—Need to match the certainty level or intent of the conclusion in the stimulus. ie: probably, always, never, should.
- Look for identical wording—these answer choices are at least contenders.
• must, could, many, some, should, never, can
- Look for synonyms
• most, majority, more than half
- Presence of a negative term is not grounds for dismissal
• present, not absent
- Stimulus can have a positive conclusion and the correct answer choice can have a negative term
• The Premises—Same wording rules as with the conclusion apply.
- Make sure that you match all premises in form and quantity. - Does not need to be parallel
• Topic of the Stimulus
• Order of presentation of the premises and the conclusion in the stimulus
- Steps to Solving:
• Match the Method of Reasoning
• Match the Conclusion
• Match the Premises
• Match the Validity of the Argument
- Fall back on describing the stimulus in abstract and matching this abstract formula with that of any possible contenders.
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Point at Issue Questions - Comprised of two speakers who disagree about an issue that is generally ethical or decisionoriented in nature, not factual.
- Question stem directs you to choose the answer that describes the point of disagreement between the two speakers or to identify the statement that the two speakers would disagree is true.
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Variant of Must Be True Questions
- Incorrect Answers in Point at Issue Questions
• Ethical vs. Factual Situations
- When a stimulus addresses an issue that is ethical in nature, answer choices that are factual
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in nature cannot be true.
• Dual Agreement or Dual Disagreement
- Incorrect answers will supply statements that both speakers will either agree or disagree with. These answers choices are attractive because they raise issues that are addressed in the stimulus; however, we need an answer that has one speaker agreeing and the other disagreeing.
• The View of One Speaker is Unknown
- This is an answer choice where the view of one speaker would be known while the view of the other would be unknown—he/she may agree or they may disagree.
- Since the correct answer must contain a point of disagreement, this answer is incorrect.
The Agree/Disagree Test
• The correct answer must produce responses where one speak would say “I agree, the statement is correct” and the other speak would say “I disagree, the statement is incorrect.”
Watch for “Point of Agreement” questions—just look for answer that both speakers would agree with.
Second Family: Help/Strengthen Family - Use the information from the answer choices to or strengthen the argument in the stimulus.
- This family includes: Assumption, Justify the Conclusion, Strengthen/ and Resolve the
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Paradox Question Types
Strengthen/ - Strengthen an argument by:
• Identifying the conclusion
• Personalizing the argument
• Looking for the weaknesses in the argument. These are the holes to you need to fill
- Correct answer can strengthen by a lot of just a little bit.
- Always try to strengthen an analogy or survey if present.
- Strengthen a Cause and Effect Relationship by:
• Eliminating any alternative causes for the effect
• Showing that when the cause occurs, the effect occurs
• Show that when the cause does not occur, the effect doesn’t either.
• Eliminate the possibility that the stated relationship is reversed
• Show that data used to make causal statement is accurate and valid. Or, eliminate any possible problems with the data.
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LSAT Notes.
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Justify the Conclusion - Strengthen the argument so powerfully that the conclusion is made to be logical without a doubt
- 100% evidence of proof
- Justify Formula:
• Premises + [Correct Answer Choice]= Conclusion
- Justify questions all conform to the following relationship:
• Answer Choice (correct) —>Conclusion (valid)
- How to Recognize Justify the Conclusion Question Stimulus
• 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
- Most Justify the Conclusion stimuli either use conditional reasoning or contain numbers and percentages
- Solve these questions by reducing the stimulus to its comment parts (premises and conclusion) and then identify which elements appear in the conclusion but not the premises. The following rules apply:
• Any “new” element in the conclusion will appear in the correct answer
• Elements that are common to the conclusion and at least one premises or to two premises, normally do not appear in the correct answer
• Elements that appear in the premises but not the conclusion normally appear in the correct answer
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Assumption Questions
- An assumption is an unstated premise of the argument. It is an integral component of the argument that the author takes for granted and leaves unsaid.
- For these questions, you need to identify a statement that the argument assumes or supposes. Usually, this is just an unstated premise and what is necessary for the argument to be true.
- The answer choice that you select as correct must contain a statement that the author relies upon and is fully committed to in the argument.
- Two Roles of Assumption Answers
• er Assumption
- Link together new or rogue elements in the stimulus or fill logical gaps in the argument.
• Defender Assumption
- Contain statements that eliminate ideas or assertions that would undermine the conclusion.
- Defend the argument by showing that a possible source of attack has been eliminated.
- Assumption Negation Technique • Use this technique to decide between contenders or to confirm that the answer you have chosen is correct.
• Logically negate answer choices under consideration
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Last Update: Sunday, December 1, 2013
LSAT Notes. • The negated answer choice that attacks the argument will be the correct answer.
- Logical Opposite is the statement that denies the truth of the original statement. • Always vs. Not Always
• Will vs. May Not
• Everywhere vs. Not Everywhere
• Could vs. Cannot
• Sometimes vs. Never
• All vs. Not All
• Somewhere vs. Nowhere.
• Some vs. None
• All of the Time vs. None of the Time
• Unless [NC]…Will Not [SC] vs. Will [SC] …even if [NC] • Sweet vs. Not Sweet
- To negate a conditional statement, you must show that the necessary condition is not, in fact, -
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necessary.
Assumptions in conditional reasoning
• Premise: A->B->C; Conclusion A->D; Assumption: C->D or contrapositive
• Deny scenarios where sufficient condition occurs and necessary does not.
• Always look for the answer that confirms that the necessary condition is truly necessary
Correct Answers for Assumption Questions • Eliminates any alternate cause for the stated effect
• Shows that when the cause occurs, the effect occurs
• Shows that when the cause does not occur, the effect does not occur
• Eliminates the possibility that the stated relationship is reversed
• Shows that the data used to make the causal statements are accurate or eliminates the possibility of problems with the data.
Assumption vs. Must Be True Questions
• In Assumption Questions, answers contain statements used to make the conclusion. These are the statements that the author must believe in order for the conclusion to be true. However, they are not explicitly stated in the stimulus
• In Must-Be-True Questions, answers contain statements that follow from arguments made in the stimulus; or, in other words, they are answers proven by the info in the stimulus and do not incorporate new info.
Three Quirks of Assumption Question Answer Choices • Watch for answers starting with the phrase “at least one” or “at least some”; these are very often the correct answer
• Avoid answers that claim and ideas was the most important for the author, ie: a top priority or their primary purpose
• Watch for the use of “not” or negatives in assumption answer choices—may be a defender answer choice and, potentially, the correct one.
Resolve the Paradox - Each RTP stimulus presents a situation where 2 ideas or occurrences contradict each other.
- Besides the discrepant or contradictory facts, most RTP stimuli contain the following features:
• No conclusion
• Language of Contradiction - But
- However
- Yet
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Although
- Paradoxically
- Surprisingly
- Question Stem Features
• An indication that the answer choices should be accepted as true
• Key words that indicate your task is to resolve a problem.
- Action Words
• Resolve, Explain, Reconcile
- Problem Words
• Paradox, Discrepancy, Contradiction, Conflict, Puzzle
- The correct answer will actively resolve the paradox—it will allow both sides to be factually -
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correct and it will either explain how the situation came into being or add a piece of new information that shows how the 2 ideas or occurrences can coexist
You are not seeking to disprove one side of the situation—you must select the answer choice that contains a a possible cause of the situation
• Ask yourself if the answer choice could lead to the situation in the stimulus. If so, correct.
Incorrect answer choices:
• Explain only one side of the paradox; the correct answer must show how both sides coexist with each other.
• Similarities and Differences
- 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
Always address the facts of the situation.
Evaluate the Argument - Combination of the Second and Third Families
- Question stems include: Evaluate, Judge, Assess
- Search for the reasoning error present.
- Answer choices are accepted as given and information in the stimulus is suspect. Task is to determine the answer choice that best helps determine the validity of the argument.
- Consider question statistic or piece of information that would best help to define the logical validity of the argument in the stimulus.
- The Variance Test • Supply two opposite responses to the question posed in the answer choice and then analyze how he varying responses affect the conclusion in the stimulus.
• If different responses produce different effects on the conclusion, the answer choice is correct.
• If different responses do not produce different effects, the answer choice is incorrect.
• Only apply to contenders.
Third Family: Hurt/Weaken Family - Use info from the answer choices to hurt/weaken the argument in the stimulus
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Look for the answer choice that undermines the author’s argument by evaluating and attacking:
• Incomplete Info
• Improper Comparison
• Qualified Conclusion (limiting)
- Rules of Weakening Questions
• The stimulus will contain an argument
• Focus on the conclusion
• The information in the stimulus is suspect. They are often reasoning errors present and you
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must read the argument very carefully
• Weaken questions often yield strong pre phrases
• The answer choices are accepted as given even if they include new information
Conclusion of the argument is the best place to attack, but the correct answer will not simply contradict the conclusion but rather undermine the conclusion by shown that the conclusion fails to for some other element or possibility.
Three Incorrect Answer Choices to Avoid:
• Opposite Answers
• Shell Game Answers
• Answers that are out of the scope of the argument
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.
fourth Family: Cannot be True Family - Use information from the stimulus to select the answer that cannot be true.
- Task is to identify the answer choice that cannot be true or is most weakened by the -
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information in the argument.
Answers that could be true are incorrect.
The stimulus in a Cannot Be True question rarely contains a conclusion
Accept the information in the stimulus and use only it to prove that one of the answer choices cannot occur
• If an answer choice contains information that does not appear directly in the stimulus or as a combination of items in the stimulus, then that answer choice could be true and thus is incorrect.
Mentally prepare yourself to eliminate the answers that could be true or a possible and select the answer that is absolutely impossible
In problems that revolve around numbers and percentages, the stimulus will often supply enough information for you to determine that certain outcomes must occur. The correct answer then violates this outcome.
In problems featuring conditional statements, many different scenarios can occur except the following:
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Last Update: Sunday, December 1, 2013
LSAT Notes. • The sufficient condition occurs but the necessary condition does not.
• Actively seek the answer above in Cannot Be True questions with conditional reasoning.
- Questions can be viewed in 2 ways:
• Polar Opposites Must Be True Question
- Instead of proving an answer, you must disprove the answer
• Reverse Weaken Question
- Use the information in the stimulus to attack one of the answers
- Look for the following question stems:
• Stating that the answer cannot be true or does not follow
• Stating that the answer could be true EXCEPT
• Stating that the answer choice must be false (not in caps, watch for this)
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Section Strategy and time Management -
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On average, the first ten questions are much easier than the last ten questions
Answer the first 10 questions as quickly as possible
Do not get caught up trying to answer 1 questions; if it is giving you problems, move.
If you have spent a minute and a half on a question, decide if you can solve or if you need to move on. If you see a clear path, continue. If not, move.
Must transfer answers during 35 minutes
Decide how many questions you want to have answered at the 10, 20 and 30 minute marks.
Re-check troublesome problems if you have time—note these problems on the side to make them easy to go back to
24 questions: 1 minute 27 seconds
25 questions: 1 minute 24 seconds
26 questions: 1 minute 20 seconds
Know strengths and weaknesses and make decisions to skip questions if necessary
As time winds down, go with gut and move on.
Three or four of the same answers in a row is okay.
Guess D.
At the very end, start with evaluating D and E answer choices.
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LSAT Logical Reasoning Premises and Conclusions | Indicators I. Premise Indicators - Because - Since - For - For Example - For the Reason That - In That II. -
Conclusion Indicators Thus
Therefore Hence Consequently As a Result So Accordingly
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Given That
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Clearly
As Indicated By Due To Owing To This Can Be Seen From We Know This By
Must Be That Shows That Conclude That Follows That For This Reason
NOTES - Premises and conclusions can be constructed without any indicator words present
- A fact set does not contain a conclusion; an argument must contain a conclusion
- Additional premise indicators includes: furthermore, moreover, besides, in addition, what’s
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more
• can be central to argument or secondary
• determine importance of these indicators by evaluating entire argument
Counter-premise indicators bring up points of opposition or comparison. Examples of these include: but, yet, however, on the other hand, ittedly, in contrast, although, even though, still, whereas, in spite of, despite, after all
Look for validity (versus truth) in LSAT arguments
If the stimulus contains an argument, determine whether the argument is strong or weak.
LSAT authors do not tend to deceive you; assume that any argument posed by the argument is believed 100%; the test producers are the ones that intend to deceive.
Always read closely and know precisely what the author said. Do not generalize.
Make sure everything is within the scope of the argument.
On average, 1 minute and 25 seconds for each questions
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Read carefully and identify the question stem Do not assume that certain words are automatically assumed with certain question types.
Question Types I. Must Be True/Most ed
A. Identify the answer choice that is best proven from the information in the stimulus
II. Main Point
A. Find the primary conclusion made by the authors
III. Point at Issue
A. Identify a point of contention between 2 speakers
IV. Assumption
A. Identify what author must assume in order for the argument to be valid
V. Justify the Conclusion
A. Supply a piece of information that, when added to the premises, proves the conclusion.
VI. Strength/
A. Select the answer choice that provides the most for the author’s argument or strengthens it in some way.
VII. Resolve the Paradox
A. Stimulus contains a discrepancy or seeming contradiction. Find the answer choice that resolves this situation
VIII.Weaken
A. Attack or undermine the author’s argument
IX. Method of Reasoning
A. Describe, in abstract , the way in which the author made their argument.
X. Flaw in the Reasoning
A. Describe, in abstract , the error of reasoning committed by the author
XI. Parallel Reasoning
A. Identify the answer choice that contains reasoning most similar in structure to the reasoning presented in the stimulus. XII.Evaluate the Argument A. Decide which answer choice allows you to determine the logical validity of the argument XIII.Cannot Be True
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A. Identify answer choice that cannot be true or is most weakened based on the information from the stimulus.
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Last Update: Sunday, December 1, 2013
LSAT Notes.
Question Types: Keys and Explained. I. Main Point Questions: Conclusion of argument is the main point. Avoid answers that may be true but don’t contain the main point or that repeat the premise of argument.
II. Must Be True: Use fact test—reference the stimulus to prove correct answer. Keep within the scope of the argument. Look for answers that combine 2+ phrases from stimulus.
III. Conditional/Formal Logic: Sufficient—-> Necessary. Contrapositive: flip the order and negate.
- Conditional Linkage: If A->B and C->A; then C->A->B or rather C->B
- Either/Or: At least one and maybe both need to be present.
- Multiple Conditions: In order to NECESSARY you must be SUFFICIENT 1 and SUFFICIENT 2; Contrapositive-If you are not SUFFICIENT 1 or SUFFICIENT 2, then you will not NECESSARY.
- Bi-Conditionals: If and only if; Either both are present or neither are present.
- Double Not Arrow: If one is present, the other cannot be.
IV. Weaken: Look for answer choice that weakens the conclusion of the argument
- Conclusion doesn’t follow premise
- Author’s assumptions
- Error of assumption
- How did the author arrive at his/her conclusion?
• Incomplete info can be weakened with new info
• Qualified conclusion—may limit the conclusion “all” “none”
• Improper comparison—2 items being compared are very different.
A. Always attack the necessary condition
V. Causal Conclusions: Always look for the assumption
VI. Strengthen: the argument (ie: the conclusion) in any way to any degree.
VII.Justify the Conclusion: Strengthen so that the conclusion is 100% proven.
- Premises + correct answer choice = the conclusion
- An answer with a new element in the conclusion will be incorrect
- If element is in premise and conclusion and answer choice, then skip it—it will probably be incorrect.
- An answer with new elements that are in premises but not conclusions
VIII.Assumption: This is the unstated premise that the argument relies on.
- er: Connects rouge pieces/info
- Defender: protects argument from ideas that could weaken conclusion.
- Assumption Negation Technique
• Logically Negate Answer Choice
• Negated answer choice will attack and weaken argument if correct answer
- Quirks to look for:
• “At lease one/some”
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Avoid answers that claim something was author’s “top priority” or “main purposes”
• Watch for “not” or negatives in A.C.
Formal Logic - This is the study of the properties of propositions and deductive reasoning by abstraction and -
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analysis of the form rather than the content of the propositions under consideration.
Standard way of translating relationships into symbols and then making inferences from those symbolized relations.
Basis for Formal Logic are such as all, none some and most Every Formal Logic Relationship features at least 2 separate variables linked in a relationship
• Variables represent groups of ideas
Diagraming Formal Logic Questions
• Choose symbols to represent each variable.
• Use conditional reasoning and diagrams (arrows)
- The Single Arrow (—>) Introduced by sufficient and necessary words/conditions. Sufficient on the left, necessary on the right. Contrapositive, flip the order and negate.
- The Double Arrow (<—>) Introduced by “if and only if ” or by situations where the author implies that the arrow goes both ways by adding like “vice versa”
• Either both variables occur or both don’t
- The Double Not Arrow (<—/—>) Introduced by conditional statements where exactly one of the is negative or by statements using words such as “no” and “none” that imply that the two variables cannot go together.
• Either Term 1, Term 2, or (in some instances) neither.
The Concept of Some
• Defined as “at least one, possibly all”
• Some are not—could mean “none”
• Ways to say “some” on the LSAT - Some
- A few
- Part of
- At least some
- A number
- A portion
- At least one
- Several
The Concept of Most
• Defined as “a majority, possibly all”
• Most are not—could mean none
• Ways to say “most” on the LSAT - Most
- More than half
- Usually
- A majority
- Almost all
- Typically There is not a contrapositive for most or some statements
Formal Logic Numerically • All= 100
• Some Are Not & Not All= 0 to 99
• Most= 51 to 100 (“a majority)
• Most Are Not= 0 to 49
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Some= 1 to 100 (at least one)
• None=0 - All and none are precise.
- The Rules of Reversibility
• The relationship between the 2 variables has exactly the same meaning regardless of which
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“side” of the relationship is the starting point of your analysis
- None, some, some are not and double arrow statements are reversible
- “Some A’s are not B’s”
• Reversal of this is “Some things that are not B are A”
• Statements that are non-reversible have a single “direction” meaning that the relationship between the 2 variables is not the same.
- All and most are non-reversible
Formal Logic Inferences • Additive: result from combining multiple statements through a common term and then deducing a relationship that does not include the common term
• Inherent: follow from a single statement. Know this inference to be true simply from the relationship between the 2 variables.
• The Logic Ladder:
- All [Most (Some)]
• The Negative Logic Ladder:
- None [Most Are Not (Some Are Not)]
Always try to make formal logic additive inferences once you have listed what’s inferred.
• Start by looking at the ends of the chain
• Vast majority of additive inferences require either an all or none statement somewhere in the chain
• 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: look for arrow that “leads away” from the some relationship
- Look for the weakest link in the chain to make inference
- The presence of relevant negativity
• The Most Train: similar to some train, but produces stronger inferences.
• Arrows and double-not arrows almost always elicit additive inferences
• Use inherent inferences
• Watch for the relevant negativity
- Either the first or last rem is negated or
- There is a double-not arrow in the chain
• Some and Most Combinations
- 2 consecutive some’s, most’s or a some and a most in succession will not yield any inferences.
• Analyze compound statements
• Once an inference bridge is built, it does not need to be built again
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Last Update: Sunday, December 1, 2013
LSAT Notes.
Conditional Reasoning - A sufficient condition can be definite as an event or circumstance whose occurrence indicates -
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that a necessary condition must also occur
A necessary condition can be defined as an event or circumstance whose occurrence is required in order for the sufficient condition to occur
Logical Features of Conditional Reasoning
• The sufficient conditional does not make the necessary condition occur. Rather, it is a sign or indicator that the necessary condition will/must occur
• Temporally speaking, either conditional can occur first—or, they can occur at the time time
• The conditional relationship statement by the author does not have to reflect reality
Develop the contrapositive by reversing the and negating. The contrapositive denies the necessary condition, thereby making it impossible for the sufficient condition to occur.
Valid and Invalid Inferences
• Repeat form simply restates the elements in the original order the appeared; valid
• Mistaken reversal (reverses the without negating); invalid
• Mistaken negation (negating both conditions but not reversing ); invalid
Sufficient Condition Indicators • If
• Every
• People Who
• When
• All
• In order to • Whenever
• Any
Necessary Condition Indicators • Then
• Must
• Except
• Only
• Required
• Until
• Only If
• Unless
• Without Unless Equation • Whatever term is modified by unless, except or without becomes the necessary condition
• The remaining term is negated and becomes the sufficient condition
When a stimulus that contains Conditional Reasoning is combined with a Must Be True questions stem, immediately look for the Repeat or Contrapositive in the answer choices.
Always look for the most difficult./longest answer—test makers like to use this as the correct answer (chain inference)
With “and/or” —If “and” is used in sufficient condition, “or” must be used in contrapositive.
Conditional reasoning can occur in many different question types
Cause and Effect Reasoning - Causality occurs when one event is said to make the other one occur. The cause is the event that makes the other occur and the effect is the event that follows from the cause
- Most causal conclusions are flawed because:
• There can be alternate explanations for the stated relationship
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Last Update: Sunday, December 1, 2013
LSAT Notes.
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Some other cause could for the effect
Some third event may have caused both the stated cause and effect
The situation may be reversed
The events may be related, but not causally
The entire occurrence could be by the result of chance.
Conditional Reasoning versus Causal Reasoning
• The chronology of the 2 events can differ.
- For cause and effect, cause must come before the effect. For conditional, order does not matter.
• The connection between the events is different.
- In cause and effect statements, the events are related in a direct way—the cause physically makes the effect happen. In conditional statements, the sufficient and necessary conditions are often related directly, but they do not have to be.
• The language used to introduce the statements is different.
- Words that introduce each type of relationship are very different. Causal indicators are active, powerful words while most conditional indicators do not possess those traits.
Causal statements can be used in the premise or conclusion of an argument.
• If causal statement is the conclusion, the reasoning is flawed.
• If it’s in the premise, the argument may be flawed, but not because of the causal statement.
Scenarios that lead to causal conclusions in LR Questions
• One event occurs before another
• Two or more events occur at the same time
If LSAT speaker concludes that the occurrence caused another, the speaker also assumes that the stated cause is the only possible cause of the effect and agh the stated cause will always produce the effect—FLAW?
In Weaken Questions, attacking a cause and effect relationship almost always consists of performing one of the following tasks:
• Find an alternative cause for the stated effete
• Show that even when the cause occurs, the effect doesn’t
• Show that although the effect occurred the cause did not
• Show that the stated relationship is reversed
• Show a statistical problem exists with the data to make the causal statement
Causal reasoning occurs in many different question types
Numbers and percentages - Words used to introduce numerical ideas: • Amount
• Total
• Sum
• Quantity
- Words used to introduce percentage ideas: • Percent
• Proportion
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• Count
• Tally • Fraction
Last Update: Sunday, December 1, 2013
LSAT Notes. • Ratio
• Incidence
• Likelihood
• Probability
• Segment
• Share
- Misconceptions Regarding Numbers and Percentages:
• Increasing percentages automatically lead to increasing numbers
• Decreasing percentages automatically lead to decreasing numbers
• Increasing numbers automatically lead to increasing percentages
• Decreasing numbers automatically lead to decreasing percentages
• Large numbers automatically mean large percentages and small numbers automatically mean
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small percentages
• Large percentages automatically mean large numbers and small percentages automatically mean small numbers
Use the following rules for Must Be True Questions
• If the stimulus contains percentages of proportion information only, avoid answers that contain hard numbers [Ex: The car market share of Company X declined this year]
- Company X sold a smaller number of cars this year
- Company X sold a greater amount of cars this year
• If the stimulus contains only numerical information, avoid answers that contain percentage or proportion information [Company Y sold fewer computers this year]
- Company Y now has a lower share of the computer market
- Company Y now has a higher share of the computer market
• If the stimulus contains both percentage and numerical information, any answer choice that contains numbers, percentages or both may be true.
Use the following rules for Weaken and Strengthen Questions
• To weaken or strengthen an argument containing numbers and percentages, look carefully for information about the total amounts —does the argument make an assumption based on one of the misconceptions discussed above?
Market Share is simply the portion of a market that a company controls. It ca be measured in either of revenues (sales) or units sold. Regardless of the size of a market, total market share always add up to 100%.. It is a comparative term.
Numerical situation hinge on three elements:
• Overall Total
• A number within the total
• Percentage within the total.
LSAT questions will often give you one of the elements, but without at least two of these elements present, you cannot make a definite judgement about what is occurring with another element.
Knowledge of a percentage is insufficient to allow you to determine anything 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.
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Last Update: Sunday, December 1, 2013
LSAT Notes.
Principle Questions - A principle is a broad rule that specifies what actions or judgements are correct in certain -
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situations
The degree of generality of principles can vary considerably
Presence of principle indicator in a question stem serves to broaden the scope of the question.
Question becomes more abstract and you must analyze the problem identify the underlying relationships
Must Be True Principle Questions
• Must us the principle presented in the stimulus and then apply it to the situation in each answer choice.
• The answer choice can address a scenario not specifically included in the stimulus; therefore, your job is to find the answer that follows from the application of the principle.
Questions are often lengthy; may be the type to skip.
In conditional principle questions, you can conclude:
• If the sufficient condition is met in one of the scenarios in the answer choice, then it can be concluded that the necessary condition occurred.
• If the necessary conditional is not met in one of the scenarios in the answer choices, then it can be concluded that the sufficient condition has not occurred.
• If the sufficient condition is not met in one of the scenarios in the answer choices, you can conclude that the necessary conniption may or may not have occurred.
• If the necessary condition is met in one of the scenarios in the answer choice, you can conclude that the sufficient condition may or may not have occurred.
Correct answer will always feature a scenario that addresses each part of the principle
Strengthen/Justify Principle Questions
• Each answer choice contains a principle that acts as an additional, board premise that s or proves the conclusion.
• Ask—“if this answer is true, does it or prove the conclusion?”
• Do not eliminate an answer because you disagree with the principle in its answer choice
• Correct answer provides a broad premise that can be added to the argument to help prove the conclusion.
When you encounter a Principle Question, prepare to apply the principle to a situation that falls under the purview of the principle but is not necessarily directly addressed by the principle.
First Family: Must Be/Prove Family 1. Must Be True
2. Main Point
3. Point at Issue
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4. Method of Reasoning
5. Flaw in Reasoning
6. Parallel Reasoning
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Take information from the stimulus to & select correct answer choice
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Last Update: Sunday, December 1, 2013
LSAT Notes. Must Be True - Correct answers will either be:
• Paraphrased Answer - These are answers that restate a portion of the stimulus in different .
- Test your ability to discern the author’s exact meaning.
- Can appear to be almost too obvious. Don’t be afraid to pick the easy/obvious choice!
• Answers that are the sum of 2 or more stimulus statements (combination answers) - Any answer choice that would result from combining 2 or more statements in the stimulus will be correct.
- Incorrect answers in must be true questions
• “Could be true” or “likely to be true” answers
- select the answer choice that must occur
• Exaggerated answers
- take information from the stimulus and then stretch that information to make a broader statement that is not ed by the stimulus.
- often paraphrased, but uses like “most,” “none,” “all,” etc.
• “New” Information Answers
- Always be wary of any answer choice that does not directly reference information that was stated in the stimulus.
- Examine the scope of the argument to make sure that information does not fall within the sphere of a term or concept in the stimulus before ruling it out.
- Examine the answer to make sure it’s not a consequence of combining stimulus elements
• The Shell Game
- An idea of concept is raised in the stimulus and then a very similar idea appears in the answer choice, but the idea is changed just enough to be incorrect, yet still attractive.
• Opposite Answer
- Answer is completely opposite of the stated facts of the stimulus.
• Reverse Answer
- Contains familiar elements but presents them in the opposite way they are supposed to be presented. Rearranges elements to create a new, uned statement
- Must be true questions require you to select an answer choice that is proven by the info presented in the stimulus.
- All MBT answer choice must the Fact Test in order to be correct.
• The correct answer to a MBT questions can always be proven by referring to the facts stated in the stimulus
- The scope of the stimulus—especially if that scope is broad—often helps to eliminate one or more of the answer choices
- Stimulus of most MBT questions do not have a conclusion/argument—really just a set of facts.
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Main Point Questions
- Incorrect Main Point Answers
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Answers that are true but do not encapsulate the author’s loin
• Answers that repeat premises of the argument
- The main point is the same as the conclusion of the argument
- Correct answer choice must not only be true according to the stimulus, it must also summarize the author’s point.
- Avoid answers that are true but miss the point of the author’s argument
- Fill in the Bank questions are Main Point questions in disguise
• emphasis of these questions is on using the contextual clues provided in the stimulus to find
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the voice that best fits the blank
Method of Reasoning - Can only use information found in the stimulus to prove the correct answer choice.
- Any answer choice that describes an element or situation that does not occur in the stimulus is incorrect
- These questions are simply abstract Must Be True questions
- Fact Test • If an answer choice describes an event that did not occur in the stimulus, that answer is incorrect.
• Watch out for answers that are partially true.
- Stimulus will contain an argument and the argument can contain either valid or invalid reasoning.
- Must watch for the presence of the premises and conclusion
- Incorrect Answers in Method of Reasoning Questions:
• New Element Answers
• Half Wrong, Half Right Answers
• Exaggerated Answers
• The Opposite Answer
• The Reverse Answer
- Argument Part Questions • Question stem cites a specific part of the stimulus and then asks you to identify the role that the cited portion plays in the structure of the argument
• These tend to be more complex than the average LSAT stimulus
• Often feature 2 conclusions—a main conclusion and a subsidiary conclusion
- The main conclusion is typically placed in the first or second sentence and the last sentence contains the subsidiary conclusion
- Subsidiary conclusion is often preceded by a conclusion indicator such as “thus” or “therefore” while the main conclusion is not prefaced by such indicator
• Avoid answers that may be correct but reference a different part of the question stem.
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Flaw in the Reasoning - Very similar to method of reasoning questions.
- Solve these questions by:
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Last Update: Sunday, December 1, 2013
LSAT Notes. • Identifying errors of reasoning made in the stimulus
• Identifying answer choices that describe a common error of reasoning
Types of Flaws I. Uncertain use of a term or concept.
- Term is not used in a constant, coherent fashion
- Ex: Depending on the ambiguous use of a key term
II. Source argument/ad hominem
- Attacks the person (or source) instead of the argument they advance
- Focusing on the motives of the source
- Focusing on the actions of the source
- Ex: Makes an attack on the character of their opponent
III. Circular Reasoning
- Author assumes as true what is supposed to be proven
- “This essay is the best because it’s better than others”
- Ex: Assumes what it seeks to establish
IV. Errors of Conditional Reasoning
- Taking the nonexistence of something as evidence that a necessary pre-condition for that thing also did not exist
- Mistakes being sufficient to justify something for being necessary
- Confuses necessary condition for a sufficient condition or vice versa
- Mistaken Negation and Mistaken Reversal
V. Mistaken Cause and Effect
- Assuming causal relationship on the basis of the sequence of events (mistakes a temporal relationship for a causal relationship)
- Assuming causal relationship when only a correlation exists (confusing the coincidence of 2 events with a causal relationship between the two.)
- Failure to consider an alternative cause for the effect of the cause and effect (fails to exclude an alternative explanation for the observed effect)
- Failure to consider that the events might be reversed
VI. Straw Man
- Attempt 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 and easier to attack in the process
- Ex: Refutes a distorted version of an opposing position
VII. General Lack of Relevant Evidence for the Conclusion
- Fail to provide any info to their conclusion
VIII.Internal Contradiction
- Authors mistakes conflicting statements
- Ex: “Bases a conclusion on claims that are inconsistent with each other”
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Last Update: Sunday, December 1, 2013
LSAT Notes. IX. Appeal to Authority
- Uses opinion of an authority in an attempt to persuade the reader
- Ex: “judgement of experts is applied to a matter in which their expertise is irrelevant”
X. Appeal to Popular Opinion/Numbers
- States that a position is true because the majority believes it to be true
XI. Appeal to Emotion
- Emotions or emotionally charged language is used as an attempt to persuade the reader
XII.Survey Errors
A. Uses biased sample that is unrepresentative of population to draw a conclusion
B. Improperly constructed questions
1. Survey questions are confusing or misleading
2. Misleading and presumes questions
C. Inaccurate Responses—people do not always tell the truth when responding to surveys
XIII.Exceptional Cause and Overgeneralization
- Takes a small number of instances and treated those instances as though they a broad, sweeping conclusion
XIV.Errors of Composition and Division
- Judgement is made about groups and parts of a group based on a characteristic of part of the group. Author attributes a characteristic of part of the group to the group as a whole or each member
XV. False Analogy
- Author uses analogy that is too dissimilar to the original situation to be accurate
XVI. False Dilemma
- Assumes only two courses of action are available when there may be others
XVII. Errors in the Use of Evidence
A. Lack of evidence for a position is taken to prove that the position is false; treats failure to prove a claim as constitutional denial of that claim.
B. Lack of evidence against a position is taken to prove that that position is true—just because there has not yet been evidence introduced to disprove a position does not mean that the position is true.
C. Evidence against a position is taken to prove that a position is false. Introduction of evidence against a position only weakens the position; it does not necessarily prove the position to be false.
D. Some evidence for a position is taken to prove that the position is true.
XVIII.Time Shift Errors
- Assuming that the conditions will remain constant over time
- Ex: “Treats a claim about what is currently the case as if it were a claim about what will happen for an extended about of time”
XIX.Numbers and Percentage Errors
- Author improperly equates a percentage with a definite quantity
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Or, uses quantity information to make a judgement about the percentage represented by that
!
quantity.
Parallel Reasoning
- Identify the answer choice that contains reasoning most similar in structure to the reasoning in the stimulus
- Parallel Flaw questions require that you find an answer choice with the same flawed reasoning
- Evaluate and Solve Parallel Reasoning Questions by examining the following items:
• Method of Reasoning—recognize the form used in stimulus and look for answer choice with the same form.
• Validity of the Argument—Validity of the reasoning in the correct answer choice must match the validity of the reasoning in the stimulus
• The Conclusion—Need to match the certainty level or intent of the conclusion in the stimulus. ie: probably, always, never, should.
- Look for identical wording—these answer choices are at least contenders.
• must, could, many, some, should, never, can
- Look for synonyms
• most, majority, more than half
- Presence of a negative term is not grounds for dismissal
• present, not absent
- Stimulus can have a positive conclusion and the correct answer choice can have a negative term
• The Premises—Same wording rules as with the conclusion apply.
- Make sure that you match all premises in form and quantity. - Does not need to be parallel
• Topic of the Stimulus
• Order of presentation of the premises and the conclusion in the stimulus
- Steps to Solving:
• Match the Method of Reasoning
• Match the Conclusion
• Match the Premises
• Match the Validity of the Argument
- Fall back on describing the stimulus in abstract and matching this abstract formula with that of any possible contenders.
!
Point at Issue Questions - Comprised of two speakers who disagree about an issue that is generally ethical or decisionoriented in nature, not factual.
- Question stem directs you to choose the answer that describes the point of disagreement between the two speakers or to identify the statement that the two speakers would disagree is true.
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Variant of Must Be True Questions
- Incorrect Answers in Point at Issue Questions
• Ethical vs. Factual Situations
- When a stimulus addresses an issue that is ethical in nature, answer choices that are factual
-
in nature cannot be true.
• Dual Agreement or Dual Disagreement
- Incorrect answers will supply statements that both speakers will either agree or disagree with. These answers choices are attractive because they raise issues that are addressed in the stimulus; however, we need an answer that has one speaker agreeing and the other disagreeing.
• The View of One Speaker is Unknown
- This is an answer choice where the view of one speaker would be known while the view of the other would be unknown—he/she may agree or they may disagree.
- Since the correct answer must contain a point of disagreement, this answer is incorrect.
The Agree/Disagree Test
• The correct answer must produce responses where one speak would say “I agree, the statement is correct” and the other speak would say “I disagree, the statement is incorrect.”
Watch for “Point of Agreement” questions—just look for answer that both speakers would agree with.
Second Family: Help/Strengthen Family - Use the information from the answer choices to or strengthen the argument in the stimulus.
- This family includes: Assumption, Justify the Conclusion, Strengthen/ and Resolve the
!
Paradox Question Types
Strengthen/ - Strengthen an argument by:
• Identifying the conclusion
• Personalizing the argument
• Looking for the weaknesses in the argument. These are the holes to you need to fill
- Correct answer can strengthen by a lot of just a little bit.
- Always try to strengthen an analogy or survey if present.
- Strengthen a Cause and Effect Relationship by:
• Eliminating any alternative causes for the effect
• Showing that when the cause occurs, the effect occurs
• Show that when the cause does not occur, the effect doesn’t either.
• Eliminate the possibility that the stated relationship is reversed
• Show that data used to make causal statement is accurate and valid. Or, eliminate any possible problems with the data.
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Last Update: Sunday, December 1, 2013
LSAT Notes.
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Justify the Conclusion - Strengthen the argument so powerfully that the conclusion is made to be logical without a doubt
- 100% evidence of proof
- Justify Formula:
• Premises + [Correct Answer Choice]= Conclusion
- Justify questions all conform to the following relationship:
• Answer Choice (correct) —>Conclusion (valid)
- How to Recognize Justify the Conclusion Question Stimulus
• 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
- Most Justify the Conclusion stimuli either use conditional reasoning or contain numbers and percentages
- Solve these questions by reducing the stimulus to its comment parts (premises and conclusion) and then identify which elements appear in the conclusion but not the premises. The following rules apply:
• Any “new” element in the conclusion will appear in the correct answer
• Elements that are common to the conclusion and at least one premises or to two premises, normally do not appear in the correct answer
• Elements that appear in the premises but not the conclusion normally appear in the correct answer
!
Assumption Questions
- An assumption is an unstated premise of the argument. It is an integral component of the argument that the author takes for granted and leaves unsaid.
- For these questions, you need to identify a statement that the argument assumes or supposes. Usually, this is just an unstated premise and what is necessary for the argument to be true.
- The answer choice that you select as correct must contain a statement that the author relies upon and is fully committed to in the argument.
- Two Roles of Assumption Answers
• er Assumption
- Link together new or rogue elements in the stimulus or fill logical gaps in the argument.
• Defender Assumption
- Contain statements that eliminate ideas or assertions that would undermine the conclusion.
- Defend the argument by showing that a possible source of attack has been eliminated.
- Assumption Negation Technique • Use this technique to decide between contenders or to confirm that the answer you have chosen is correct.
• Logically negate answer choices under consideration
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Last Update: Sunday, December 1, 2013
LSAT Notes. • The negated answer choice that attacks the argument will be the correct answer.
- Logical Opposite is the statement that denies the truth of the original statement. • Always vs. Not Always
• Will vs. May Not
• Everywhere vs. Not Everywhere
• Could vs. Cannot
• Sometimes vs. Never
• All vs. Not All
• Somewhere vs. Nowhere.
• Some vs. None
• All of the Time vs. None of the Time
• Unless [NC]…Will Not [SC] vs. Will [SC] …even if [NC] • Sweet vs. Not Sweet
- To negate a conditional statement, you must show that the necessary condition is not, in fact, -
-
-
-
!
necessary.
Assumptions in conditional reasoning
• Premise: A->B->C; Conclusion A->D; Assumption: C->D or contrapositive
• Deny scenarios where sufficient condition occurs and necessary does not.
• Always look for the answer that confirms that the necessary condition is truly necessary
Correct Answers for Assumption Questions • Eliminates any alternate cause for the stated effect
• Shows that when the cause occurs, the effect occurs
• Shows that when the cause does not occur, the effect does not occur
• Eliminates the possibility that the stated relationship is reversed
• Shows that the data used to make the causal statements are accurate or eliminates the possibility of problems with the data.
Assumption vs. Must Be True Questions
• In Assumption Questions, answers contain statements used to make the conclusion. These are the statements that the author must believe in order for the conclusion to be true. However, they are not explicitly stated in the stimulus
• In Must-Be-True Questions, answers contain statements that follow from arguments made in the stimulus; or, in other words, they are answers proven by the info in the stimulus and do not incorporate new info.
Three Quirks of Assumption Question Answer Choices • Watch for answers starting with the phrase “at least one” or “at least some”; these are very often the correct answer
• Avoid answers that claim and ideas was the most important for the author, ie: a top priority or their primary purpose
• Watch for the use of “not” or negatives in assumption answer choices—may be a defender answer choice and, potentially, the correct one.
Resolve the Paradox - Each RTP stimulus presents a situation where 2 ideas or occurrences contradict each other.
- Besides the discrepant or contradictory facts, most RTP stimuli contain the following features:
• No conclusion
• Language of Contradiction - But
- However
- Yet
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Although
- Paradoxically
- Surprisingly
- Question Stem Features
• An indication that the answer choices should be accepted as true
• Key words that indicate your task is to resolve a problem.
- Action Words
• Resolve, Explain, Reconcile
- Problem Words
• Paradox, Discrepancy, Contradiction, Conflict, Puzzle
- The correct answer will actively resolve the paradox—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 new information that shows how the 2 ideas or occurrences can coexist
You are not seeking to disprove one side of the situation—you must select the answer choice that contains a a possible cause of the situation
• Ask yourself if the answer choice could lead to the situation in the stimulus. If so, correct.
Incorrect answer choices:
• Explain only one side of the paradox; the correct answer must show how both sides coexist with each other.
• Similarities and Differences
- 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
Always address the facts of the situation.
Evaluate the Argument - Combination of the Second and Third Families
- Question stems include: Evaluate, Judge, Assess
- Search for the reasoning error present.
- Answer choices are accepted as given and information in the stimulus is suspect. Task is to determine the answer choice that best helps determine the validity of the argument.
- Consider question statistic or piece of information that would best help to define the logical validity of the argument in the stimulus.
- The Variance Test • Supply two opposite responses to the question posed in the answer choice and then analyze how he varying responses affect the conclusion in the stimulus.
• If different responses produce different effects on the conclusion, the answer choice is correct.
• If different responses do not produce different effects, the answer choice is incorrect.
• Only apply to contenders.
Third Family: Hurt/Weaken Family - Use info from the answer choices to hurt/weaken the argument in the stimulus
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Last Update: Sunday, December 1, 2013
LSAT Notes. - Look for the answer choice that undermines the author’s argument by evaluating and attacking:
• Incomplete Info
• Improper Comparison
• Qualified Conclusion (limiting)
- Rules of Weakening Questions
• The stimulus will contain an argument
• Focus on the conclusion
• The information in the stimulus is suspect. They are often reasoning errors present and you
-
-
!
must read the argument very carefully
• Weaken questions often yield strong pre phrases
• The answer choices are accepted as given even if they include new information
Conclusion of the argument is the best place to attack, but the correct answer will not simply contradict the conclusion but rather undermine the conclusion by shown that the conclusion fails to for some other element or possibility.
Three Incorrect Answer Choices to Avoid:
• Opposite Answers
• Shell Game Answers
• Answers that are out of the scope of the argument
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.
fourth Family: Cannot be True Family - Use information from the stimulus to select the answer that cannot be true.
- Task is to identify the answer choice that cannot be true or is most weakened by the -
-
information in the argument.
Answers that could be true are incorrect.
The stimulus in a Cannot Be True question rarely contains a conclusion
Accept the information in the stimulus and use only it to prove that one of the answer choices cannot occur
• If an answer choice contains information that does not appear directly in the stimulus or as a combination of items in the stimulus, then that answer choice could be true and thus is incorrect.
Mentally prepare yourself to eliminate the answers that could be true or a possible and select the answer that is absolutely impossible
In problems that revolve around numbers and percentages, the stimulus will often supply enough information for you to determine that certain outcomes must occur. The correct answer then violates this outcome.
In problems featuring conditional statements, many different scenarios can occur except the following:
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Last Update: Sunday, December 1, 2013
LSAT Notes. • The sufficient condition occurs but the necessary condition does not.
• Actively seek the answer above in Cannot Be True questions with conditional reasoning.
- Questions can be viewed in 2 ways:
• Polar Opposites Must Be True Question
- Instead of proving an answer, you must disprove the answer
• Reverse Weaken Question
- Use the information in the stimulus to attack one of the answers
- Look for the following question stems:
• Stating that the answer cannot be true or does not follow
• Stating that the answer could be true EXCEPT
• Stating that the answer choice must be false (not in caps, watch for this)
!
Section Strategy and time Management -
! !
On average, the first ten questions are much easier than the last ten questions
Answer the first 10 questions as quickly as possible
Do not get caught up trying to answer 1 questions; if it is giving you problems, move.
If you have spent a minute and a half on a question, decide if you can solve or if you need to move on. If you see a clear path, continue. If not, move.
Must transfer answers during 35 minutes
Decide how many questions you want to have answered at the 10, 20 and 30 minute marks.
Re-check troublesome problems if you have time—note these problems on the side to make them easy to go back to
24 questions: 1 minute 27 seconds
25 questions: 1 minute 24 seconds
26 questions: 1 minute 20 seconds
Know strengths and weaknesses and make decisions to skip questions if necessary
As time winds down, go with gut and move on.
Three or four of the same answers in a row is okay.
Guess D.
At the very end, start with evaluating D and E answer choices.
page 2! 0
Last Update: Sunday, December 1, 2013
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