Month: November 2017

Flaws: Mistaken Most

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

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

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

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

Flaws: Subjective/Objective Problem

Some flawed LSAT arguments infer a person’s intent from his or her actions (or vice versa).  If I were to accidentally knock a child down, I would not necessarily be guilty of child abuse.

This “subjective/objective” problem shows up periodically on the LSAT, but it is not otherwise common enough to be listed as a major fallacy. It only appears twice in 10 Actual Official LSAT Preptests, Volume VI (once as a correct answer and once as a wrong answer).

  • 72-2-5: Firepower movie (Vol VI, p. 16). 83% identified this as the correct answer to this “medium difficulty” question.
  • 74-4-18: Melatonin (Vol VI, p. 116). 7% chose this wrong answer to this “hardest difficulty” question.

Volume VI Flaws

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

I recommend that this document be used as part of the 7Sage “blind review” method. Try to figure out each flaw question on your own, and then, without checking your  answer, look at that question in this document.  If you aren’t familiar with the labels I use  to describe the different flaws, just click the hyperlink to see what Wikipedia or other authors have said about this specific flaw. Then, after you are clear on what each answer actually means, choose your answer. If it is the same answer you originally chose, congratulations! If you changed your answer, congratulations again–you may have just learned something that will help you get into the law school of your choice!

72-2-5: Firepower movie (p. 17)

  1. Ad hominem
  2. Correlation does not imply causation
  3. Fallacy of composition
  4. Overlooked possibility
  5. Subjective/objective problem

72-2-14: Chocolate depression (p. 19)

  1. Reducing cause eliminates effect
  2. Unrepresentative sample
  3. Correlation does not imply causation
  4. Mistaken reversal
  5. Vague conclusion

72-2-16: Too many artworks (p. 20)

  1. Overlooked possibility
  2. Assumption
  3. Assumption
  4. Overlooked possibility
  5. Assumption

72-2-18: Blood samples (p. 20)

  1. Assumption
  2. Overlooked possibility
  3. Overlooked possibility
  4. Overlooked possibility
  5. Assumption

72-2-20: Wild apples (p. 21)

  1. Overlooked possibility
  2. Overlooked possibility
  3. Assumption
  4. Internal contradiction
  5. Circular reasoning

72-2-22: Flawed pattern (p. 22) is a mistaken reversal

72-3-7: Comics and health (p.26)

  1. Overlooked possibility
  2. Overlooked possibility
  3. Assumption
  4. Assumption
  5. Assumption

72-3-11: Hiking trail (p. 27)

  1. Argument from ignorance
  2. Fallacy of composition
  3. Circular reasoning
  4. Hasty generalization
  5. Ad hominem

72-3-14: Wildlife activists (p. 28)

  1. Mistaken negation
  2. Complete rejection of partial solution
  3. Overlooked possibility
  4. Ad hominem
  5. Rejection of one possible solution

72-3-22: Pathogenic microorganisms (p. 30)

  1. Overlooked possibility
  2. Overlooked possibility
  3. Overlooked possibility
  4. Overlooked possibility
  5. Overlooked possibility

72-3-25: Flawed pattern (p. 31) is a false dilemma

73-2-3: Movie rights to video games (p. 56)

  1. Hasty generalization
  2. Mistaken inference
  3. Circular reasoning
  4. Assumption
  5. Mistaken reversal

73-2-5: Primeval atom (p. 57)

  1. Appeal to authority
  2. Equivocation
  3. Correlation does not imply causation
  4. Evidence may support more than one hypothesis
  5. False dilemma

73-2-7: Flawed pattern (p. 58) is ad hominem

73-2-13: Crime rate (p. 59)

  1. Assumption
  2. Overlooked possibility
  3. Overlooked possibility
  4. Assumption
  5. Assumption

73-2-15: Advertising campaign (p. 60)

  1. Assumption
  2. Overlooked possibility
  3. Assumption
  4. Assumption
  5. Mistaken reversal

73-2-18: Planimetric art (p.61)

  1. Ad hominem
  2. Equivocation
  3. Mistaken reversal
  4. Internal contradiction
  5. Argument from ignorance

73-4-3: Sunscreen lotions (p. 73)

  1. Assumption
  2. Overlooked distinction
  3. Overlooked possibility
  4. Statistical error
  5. Overlooked possibility

73-4-10: Vacuum cleaner (p. 74)

  1. Overlooked possibility
  2. Assumption
  3. Assumption
  4. Overlooked possibility
  5. Overlooked possibility

73-4-18: Flawed pattern (p. 77) is the gambler’s fallacy

73-4-25: Roberta is irritable  (p. 79)

  1. Correlation does not imply causation
  2. Circular reasoning
  3. Hasty generalization
  4. Mistaken reversal
  5. Mistaken reversal

74-1-5: Children’s television (p. 89)

  1. Mistaken reversal
  2. Argument from ignorance
  3. Ad hominem
  4. Appeal to authority
  5. Internal contradiction

74-1-16: Pedagogical practice (p. 92)

  1. Concedes opponent’s assumption
  2. Assumption
  3. Overlooked possibility
  4. Equivocation
  5. Assumption

74-1-18: Sleep deprivation (p. 93)

  1. Alternate cause
  2. Alternate cause
  3. Mistaken reversal
  4. Assumption
  5. Overlooked possibility

74-1-25: Flawed pattern (p. 95) is mistaken reversal

74-4-8: Kodiak bear (p. 114)

  1. Hasty generalization
  2. Overlooked possibility
  3. Equivocation
  4. False dilemma / Assumption
  5. Appeal to authority

74-4-15: Interest rates (p. 115)

  1. Relies on experts
  2. Confuses terms
  3. Assumption
  4. Mistaken negation
  5. Unwarranted inference

74-4-18: Melatonin (p. 116)

  1. Subjective/objective problem
  2. Bias
  3. Equivocation
  4. Reverse cause
  5. Unrepresentative sample

74-4-20: Global recessions (p. 117)

  1. Circular reasoning
  2. Fails to establish claim
  3. Circular reasoning
  4. Overlooked possibility
  5. Possibility v. Certainty

74-4-22: Fish with teeth (p. 117)

  1. Correlation does not imply causation
  2. Argument from ignorance
  3. Mistaken negation
  4. Possibility v. Certainty
  5. Appeal to authority

74-4-25: Flawed pattern (p. 119) is a mistaken most

75-1-7: Sherwood opposes higher taxes (p. 130)

  1. Unrepresentative sample
  2. Overlooked possibility
  3. Mistaken negation
  4. Ad hominem
  5. Fallacy of division

75-1-12: Duke of Acredia (p. 131)

  1. Overlooked possibility
  2. Contrapositive (not a flaw)
  3. Unreliable evidence
  4. Correlation does not imply causation
  5. Assumption

75-1-18: Police graft (p. 132)

  1. Hasty generalization
  2. Overlooked possibility
  3. Appeal to character
  4. Assumption
  5. Internal contradiction

75-1-22: Flawed pattern (p. 134) is mistaken most

75-3-7: Profit projections (p. 145)

  1. Assumption
  2. Overlooked distinction
  3. Overlooked possibility
  4. Hasty generalization
  5. Equivocation

75-3-10: Television host (p. 146)

  1. Argument from ignorance
  2. Circular reasoning
  3. Appeal to authority
  4. Confuses standards
  5. Questions conclusion merely because it was reached quickly

75-3-14: Flawed pattern (p. 147) is unique

75-3-16: Planned locomotion (p. 148)

  1. Mistaken reversal
  2. Assumption
  3. Assumption
  4. Assumption
  5. Assumption

74-3-18: Consumer advocate (p. 149)

  1. Mistaken reversal
  2. Overlooked possibility
  3. Unrepresentative sample
  4. Assumption
  5. Assumption

76-2-1: Reptile hormones (p. 176)

  1. Provides no explanation for other abnormalities
  2. Overlooked possibility (resolves the mistaken reversal in the stimulus)
  3. Overlooked possibility
  4. Overlooked possibility
  5. Unrepresentative sample

76-2-4: Chameleon behavior (p. 177)

  1. Hasty generalization
  2. Fails to explain
  3. Appeal to authority
  4. Fails to demonstrate
  5. Holds critics to a higher standard

76-2-16: Legislature survey (p. 180)

  1. Is/ought problem
  2. Circular reasoning
  3. Fallacy of composition
  4. Survey error
  5. Rough estimates yield precise conclusion

76-2-19: Union leaders (p. 181)

  1. Genetic fallacy
  2. Assumption
  3. Genetic fallacy
  4. Assumption
  5. Assumption

76-2-21: Flawed pattern (p. 182) is multiple causes

76-4-5: Traditional rituals (p. 193)

  1. Assumption
  2. Assumption
  3. Assumption
  4. Assumption
  5. Assumption

76-4-6: Flawed pattern (p. 193) is affirming a disjunct

76-4-13: Government statistics (p. 195)

  1. Equivocation
  2. Overlooked possibility
  3. Overlooked possibility
  4. Overlooked possibility
  5. Assumption

76-4-15: Nutritional supplements (p. 195)

  1. Equivocation
  2. Appeal to authority
  3. Appeal to emotion
  4. Ad hominem
  5. Assumption

77-2-5: Flawed pattern (p. 217) is unique.

77-2-14: Cancer and pollutants (p. 220)

  1. Overlooked possibility
  2. Overlooked possibility
  3. Assumption
  4. Overlooked possibility
  5. Overlooked possibility

77-2-18: Shakespeare snobs (p. 221)

  1. Assumption/Ad hominem
  2. Assumption
  3. Overlooked possibility
  4. Overlooked possibility
  5. Circular reasoning

77-2-22: More than one newspaper (p. 222)

  1. Confuses inabilities
  2. Overlooked possibility
  3. Is/ought problem
  4. Assumption
  5. Concerned only with important stories

77-4-6: Popular sports (p. 233)

  1. Correlation does not imply causation
  2. Hasty generalization
  3. Equivocation
  4. Circular reasoning
  5. Ad hominem

77-4-9: Joshi campaign (p. 234)

  1. Correlation does not imply causation
  2. Mistaken reversal
  3. Is/ought problem
  4. Reverse causation
  5. Circular reasoning

77-4-12: Movie critics (p.235)

  1. Argument from ignorance
  2. Overlooked possibility
  3. Unrepresentative sample
  4. Ad hominem
  5. Overlooked possibility

77-4-25: Flawed pattern (p. 239) is hasty generalization

78-1-7: Air traffic (p. 249)

  1. Hasty generalization
  2. Overlooked possibility
  3. Overlooked possibility
  4. Argument from ignorance
  5. Overlooked possibility

78-1-9: Prairie plants (p. 250)

  1. Reverse causation
  2. Fails to describe mechanism
  3. Assumption
  4. Unrepresentative sample
  5. Numbers v. Percents

78-1-21: Flawed pattern (p. 254) is “‘or’ does not equal ‘and’.” (This is an especially difficult question because the phrase “sand or organic material, or both” sounds so plausible. If you replace “organic material” with “pixie dust,” however, the flaw becomes apparent.)

78-1-22: Toxic chemicals (p. 254)

  1. Internal contradiction
  2. Overlooked possibility
  3. Argument from ignorance
  4. Reverse causation
  5. Overlooked possibility

78-3-1: Nonprofit  organization (p. 264)

  1. Unrepresentative sample
  2. Assumption
  3. Survey error
  4. Relies on majority opinion to determine minority opinion
  5. Assumption

78-3-5: Site drainage (p. 265)

  1. Overlooked possibility
  2. Overlooked possibility
  3. Overlooked possibility
  4. Overlooked possibility
  5. Overlooked possibility

78-3-15: Good manager (p. 267)

  1. Confuses qualities
  2. Confuses qualities
  3. Mistaken reversal
  4. Overlooked possibility
  5. Assumption

78-3-25: Flawed pattern (p. 271) is mistaken most.

79-1-2: Trusting neighbors (p. 288)

  1. Mistaken negation
  2. Is/ought problem
  3. Internal contradiction
  4. Circular reasoning
  5. Reverse causation

79-1-6: Body size (p. 289)

  1. Alternate causation
  2. Unrepresentative sample
  3. Alternate causation
  4. Fallacy of division
  5. Hasty generalization

79-1-13: Zoo animals (p. 291)

  1. Assumption
  2. Hasty generalization
  3. Straw man
  4. Mistaken reversal
  5. Rejects a claim because its proponent holds an inconsistent view

79-1-15: Success and luck (p. 291)

  1. Mistaken reversal
  2. Appeal to authority
  3. Circular reasoning
  4. Reverse causation
  5. Ad hominem

79-1-26: Flawed pattern (p. 295) is “some dogs are pets but no cats are dogs so no cats are pets.”

79-4-9: Fitness experts (p. 314)

  1. Correlation does not imply causation
  2. Assumption
  3. Infers that a factor that is a contributor is the only contributor
  4. Hasty generalization
  5. Fallacy of division

79-4-16: Flawed pattern (p. 316) is mistaken reversal

79-4-18: High school graduates (p. 316)

  1. Fails to establish
  2. Overlooked possibility
  3. Assumption
  4. Assumption
  5. Assumption

80-1-2: Hair dryers (p. 328)

  1. Numbers v. Percents
  2. Does not provide specific information
  3. Fails to discuss sales figures
  4. Overlooked possibility
  5. Provides no independent evidence

80-1-13: Purpose of laws (p. 331)

  1. Mistaken negation
  2. Correlation does not imply causation
  3. Equivocation
  4. Is/ought problem
  5. Fallacy of division

80-1-16: Commercial flights (p.332)

  1. Assumption
  2. Overlooked possibility
  3. Ad hominem
  4. Assumption
  5. Argument from ignorance

80-1-24: Flawed pattern (p. 335) is mistaken most

80-4-1: Community cleanup (p. 352)

  1. Hasty generalization
  2. Assumption
  3. Mistaken reversal
  4. Overlooked possibility
  5. No true Scotsman

80-4-11: University food vendor (p. 355)

  1. Overlooked possibility
  2. Unrepresentative sample
  3. Overlooked possibility
  4. Overlooked possibility
  5. Argues that a popular position ought to be adopted

80-4-16: Software company logo (p. 356)

  1. Correlation does not imply causation
  2. Mistaken negation
  3. Fallacy of division
  4. Circular reasoning
  5. Hasty generalization

80-4-23: Flawed pattern (p. 358) is roll the dice

80-4-26: Macedonian tombs (p. 359)

  1. Assumption
  2. Assumption
  3. Does not show
  4. Fails to evaluate
  5. Assumption

81-2-8: Employee bonuses (p. 377)

  1. Overlooked possibility
  2. Overlooked possibility
  3. Fails to justify
  4. Fallacy of division
  5. Assumption

81-2-20: Voting records (p. 381)

  1. Faulty comparison
  2. Fails to take into account
  3. Provides evidence but not explanation
  4. Reverse causation
  5. Overlooked possibility

81-2-24: Flawed pattern (p. 383) is argument from ignorance

81-2-25: Technological innovations (p. 383)

  1. Circular reasoning
  2. Argument from ignorance
  3. Stronger evidence than conclusion requires
  4. Mistaken reversal
  5. Hasty generalization

81-3-7: Economic productivity (p. 386)

  1. Assumption
  2. Assumption
  3. Unfairly criticizes politicians in general
  4. Assumption
  5. Fails to address

81-3-9: Brain area (p. 386)

  1. Assumption
  2. Overlooked possibility
  3. Hasty generalization
  4. Overlooked possibility
  5. Assumption

81-3-13: Legislator investment (p. 388)

  1. Treats a character trait as evidence of a viewpoint
  2. Fails to address the argument
  3. Assumption
  4. Assumption
  5. Overlooked possibility

81-3-15: Car manufacturers (p. 388)

  1. Hasty generalization
  2. Assumption
  3. Overlooked possibility
  4. Assumption
  5. Equivocation

81-3-23: Negotiated legislation (p. 391)

  1. Circular reasoning
  2. Mistaken negation
  3. Equivocation
  4. Assumption
  5. Bases conclusion on a different principle