presents someone else's claim then rejects the validity of the claim through a personal attack. 

e.i. dismisses because of the source and not the substance

"We should not accept the health inspectors findings, he is the husband of the president of the council of restaurant owners and this would benefit financially."

- The author rejects the claim because of its source rather than its content

- The argument attempts to discredit a theory by discrediting those who espouse that theory

-The argument is flawed in that it criticizes the specialist's motives for holding a position rather than the position itself

An authority speaking outside their realm of expertise 

Difference between Ad Hominem and Appeal to Ina

instead of discrediting theory by pointing out its source, Appeal to Inappropriate Authority support a theory by introducing a source that may not be reliable

i.e. Ben Carson, heart surgeon, making policy on health insurance

Flaws: Appeal to Inappropriate Authority (How to ID)

- These arguments all cite an expert opinion to support a conclusion

- Ask yourself if there is any evidence other than the expert opinion cited

- Ask yourself whether its clear that the expert cited actually has relevant expertise in the area relevant to the conclusion

- It appeals to the fact that supposed experts have endorsed the argument's main conclusion rather than appealing to direct evidence for that conclusion

-The argument fails to recognize that expertise in one area of medicine does not imply expertise in all areas of medicine

says something is untrue because it hasn't been proven

refers to arguments that prove that something is untrue based on evidence that says only that hasn't been sufficiently proven 

Types of Sub-Categories 

1. Concluding that something doesn't exist because we can't prove that it does

2. Concluding that something is incorrect because it lacks support or the support is flawed

3. Concluding that something is real or correct because we can't prove that it is false

i.e. There is not definite proof that ghosts are real, therefore ghosts do not exist

-The author takes a failure to prove a certain claim as proof that the claim is false

-The author fails to consider that a claim that was believed for questionable reasons is nonetheless true

-Look for discussions of compromise or insufficient evidence in the premises with phrases such as "failed to prove" or "disproven"

-Remember that a lack of evidence never disproves something. Without evidence we can't say whether the conclusion is true or false

-It only considers two options or groups and doesn't consider third or other options

i.e. You can travel to Las Vegas by bus or by plane since Rosie can't afford to take a plane she will go by bus

-Be on the lookout for two groups or options

-Sometimes both options will appear in the premises, other times an argument will rule out one possibility in the premise and arrive at some other previously unmentioned possibility in the conclusion.

-Whenever you see a binary relationship in a flaw question ask yourself "Are there any other options here that are being overlooked?" 

- The author fails to consider that there may be other...

-The author neglects to rule out competing options

-Apply a small sample to generalize to a larger group

-Ask yourself:

1. Is it a robust enough sample size to draw the conclusion?

2. Does the sample seem representative of the group that the conclusion is about?

3. Is there a concern about biased or pressured responses to the survey? (Who self-selected into the sample? Did they self-select?)

-Apply a small sample to generalize to a larger group

-Ask yourself:

1. Is it a robust enough sample size to draw the conclusion?

2. Does the sample seem representative of the group that the conclusion is about?

3. Is there a concern about biased or pressured responses to the survey? (Who self-selected into the sample? Did they self-select?)

-Notice that the basis for the conclusion is one example, testimonial, survey, or sample

-Assess the sample size and representativeness of the sample

-Verify that the author's conclusion extrapolates away from the evidence

-It generalizes too hastily from a potentially atypical sample

-It bases a general conclusion on too few examples

-It takes for granted the observed students are representative of students in general

- Generally two forms:

x is similar to y in one respect, so it must be similar in another respect

x is dissimilar to y in one respect so we conclude that they are dissimilar in someother respects

i.e. Rosie's pies are sweeter than Katie's therefore Rosie's pies are not as nutritious

-Notice that two things are held up as similar, dissimilar, or analogous 

-Consider what might be missing or faulty in the comparison

-Explicit: 

i.e. treats as similar two cases that are different in a critical respect

-Implicit:

i.e. takes for granted that sweeter foods are less nutritious

i.e. the argument overlooks the possibility that factors other than sweetness influence the nutritional value of a food

-Causation flaw usually incorrectly provides a correlation as evidence

1. Statistical: People who are A are more likely to be B than people who are not, thus A causes B

i.e. Women's college graduates are more likely to be better than other people, thus going to a women's college causes you to be better than other people

2. Temporal: A happens. Then B happens. Thus A caused B.

i.e. The plate dropped. The plate breaks. Therefore dropping the plate caused the plate to break.

-Even if you can't think of specific alternatives for the cause, 

1. Recognize the explicit claim or implicit assumption the author makes about causation.

2. Stay open to answer choices that suggest possible alternative modes of causation

Common wording:

-It mistakes an effect for a cause

-It fails to consider that an association between two things might be due to their common relationship to a third factor.

Condition: If we are in Boston, we are in Massachusetts (A--> B)

Contrapositive: We are not in Massachusetts then we are not in Boston

(-B--> -A)

-Illegal Reversal

If we are in Massachusetts then we are in Boston (we are actually in Cambridge!)

(B-->A)

-Illegal Negation

If we are not in Boston then we are not in Massachusetts

(-A-->-B)

-Argument joins from one term in the premise to a different term in the conclusion.

When there is a new idea in the conclusion 

ex. The boy is the best so therefore he is well-behaved

-which of the following is required for the argument to hold?

-the argument depends on which one of the following assumptions?

-which one of the following assumptions is necessary for the argument to hold?

1. Assumption Question

2. Flaw Questions

3. Assumption Family Process

4. Strengthen & Weaken Questions

5. Principle Support Questions

6. Conditional Logic

7. Principle Example Question

8. Analyze the Argument 

9. Inference

10. Matching 

uses the same word or concept in two different ways

i.e. At Michael's office, only employees with the most seniority get the closest parking space. Since Creed is the only senior citizen at Michael's office, he gets the parking space. 

- It uses the term "____" in two different ways

- It equivocates with regard to a central concept

- It trades on an ambiguity in the term "_____"

mistakes a percentage for a total amount

i.e. 2/3 of hunters support fishing for recreation. 1/3 of hunters do not support fishing for recreation. Thus, most people support fishing for recreation. 

Whenever a comparison between two percentages (or fractions) is used to make a point, compare the totals from which those two percentages are drawn

Correct answer: "substitutes one group for a different group in the statement of a percentage" 

Premise and the Conclusion are the same

Believe X. Why? Because X is true?

i.e. Chocolate is the best flavor of ice cream because all other flavors are inferior. 

- It assumes what it seeks out to prove

-It presupposes what it seeks to establish

-The conclusion is merely a restatement of the premise

Flaws: Self-Contradiction

- usually in the wrong answers

- says things are good and bad at the same time, contradicting the statements

-It bases its conclusion on claims that are inconsistent with each other

-It contains premises that cannot all be true

extends characterizations to the entire group or vise/versa

Looks like sampling flaws, but instead of drawing statistical conclusions, they are drawn to every member of the group

i.e. It is impossible to do science without measuring. It is impossible to measure without first selecting a unit of measurement. Hence, science is arbitrary, since units of measurement are always arbitrary

-The author takes for granted that a characteristic of each part of the event must also be true of the whole event

-The author infers that each part of a system has a certain property on the basis that the system itself has that property

1. What is my task?

2. What is the authors conclusion?

3. How is the conclusion supported?

4. What is the gap?

5. Which answer choices are clearly wrong?

6. What is the best answer available?

choose a principle that helps justify or support the argument

"assumptions with egos"

i.e.

Premise: The chair in the corner is an antique

Conclusion: The chair in the corner should be sold at auction

Principle: (Antiques should be sold at auction)

1. What is my task? 

i.e. are we looking for weakened answers? strengthen?

2. What is the conclusion?

3. How is this conclusion supported?

4. What is the gap?

5. Which answer choices are clearly wrong?

i.e. work from wrong to right

6. What is the best available answer?

1. The answer has no direct bearing on the conclusion

2. The answer has an unclear bearing on the conclusion

3. The answer plays an opposite role to the conclusion

most challenging of the LR section

Eliminate four answers first, then pick the right one

i.e. four answers weaken, 1 DOES NOT weaken

1. Identify the argument core (premise->conclusion)

2. Evaluate the logic: does it hold?

3. What's the gap?

4. What assumptions are being made?

1. Assumption 

i.e. What is the argument assuming?

2. Flaw

i.e. What is the flaw in this assumption?

3. Strengthen

i.e. Which of the following would strengthen this argument?

4. Weaken

i.e. Which of the following would weaken this argument?

5. Principle Support

i.e. Which of the principles, if valid, helps justify the authors reasoning?

1. "Support" (most common)

i.e. The statement above, if true, most strongly support which one of the following?

2. "Must be true" or "Must be false" 

i.e. If the statements above are true, which one of the following must be true?

3. "Infer"

i.e. Which one of the following can be properly inferred from the statements above?

4. "Completes the argument" (Fill in the blank)

i.e. Which one of the following most logically completes the argument?

5. "Follows logically"

i.e. Which one of the following claims follows logically from the statements?

1. Reverse Logic

i.e. A-B = B-A

2. Degree 

i.e. "All", "Most", "None"

3. Generalization

i.e. Specific Facts ---> Generalization

4. Scope

i.e. Answer is out of scope

5. Detail Creep 

i.e. Small shift in topic matter

Definite Answers vs. Most Likely Answers

1. Which of the following must be true?

Which of the following can we infer?

i.e. There is a definite correct answer

2. Which of the following is most strongly supported by the statement above? 

i.e. Most likely the correct answer

1. Read the question stem first

-there is no core in the stimulus on inference questions

-watch out for the word support (can be on both assumption questions and inference questions)

2. Think Literally

-make LSAT inferences, not real world inferences

-probably wont be able to predict the answer

3. Watch out for

-Degree

-Detail Creep

-Generalization

-Reverse Logic 

-Scope

-which one of the following, if true, most strengthens the argument?

-which one of the following, if true, most supports the argument?

-which one of the following, if true, does the most to justify the argument?

-each of the following, if true, strengthens the argument EXCEPT:

-which one of the following, if true, most weakens the argument?

-which one of the following, if true, most calls into question the argument?

-which one of the following, if true, most severely undermines the argument?

-each of the following, if true, weakens the argument EXCEPT:

Generally two types of answer choices:

-Directly bridges the gap between the premise and the conclusion

-Bring in an element that validates the assumption 

(could be something new) 

- Disconnect the premise and the conclusion

-bring in an element that weakens the assumption

non-assumption family. Asked to match the principle with an example

Is this criteria being met?

-the argument is most vulnerable to the criticism on the ground that it...

-the reasoning that the argument is flawed is because the argument...

-which of the following indicates a weakness?

Most Strongly Supports -the statement above, if true, most strongly support which one of the following?

Must be True-if the statements above are true, which one of the following must be true?

Infer - which one of the following can be properly inferred from the statement above?

-which one of the following conclusions can be properly drawn from the statement above?

Completes the argument (fill in the blank)- which one of the following most logically completes the argument?

Follows Logically - which one of the claims follows logically from the statements?

most obvious or modest answer 

-which one of the following, if true, most helps to explain...?