Logical Reasoning Flashcards
What two ways can the necessary or sufficient conditions be linked in a sufficient assumption question?
1) Evidence: D->E
Conclusion: D->F
Sufficient assumption: E->F
2) Evidence: A->B
Conclusion: C->B
Sufficient assumption: C->AWhat are the three common sufficient assumption formulas?
1) Restatement or broadening of argument /conclusion
2) Contrapositive of argument/conclusion
3) Linking of necessary or sufficient conditions
What is the 5 step approach to logical reasoning questions?
1) Identify question type by reading QUESTION STEM
2) Determine whether stimulus contains fact set or argument
3) if FACT SET - try to make connections between parts
4) if ARGUMENT - determine reasonability of argument
5) Pre-phrase answer or start by eliminating answer choices
What are some evidence indicator words?
Because, follows, for, since, the reason being
What are some conclusion indicator words?
As such, consequently, demonstrates, establishes, hence, it follows that, so, thus, therefore
What are some sufficient condition (before arrow) indicator words?
All, any, each, every, if, in order to, people who, the only, to be, when, whenever
What are some necessary condition (after arrow) indicator words?
Depends upon, must, only, only if, only when, only where, requires, then, until
What is the unless/except/until/without formula?
Take “unless” or similar word as introducing the necessary condition, negate other part of sentence to make it the sufficient condition
“No X unless Y” = If X -> Y
What is the quantity value of “all”?
100%
What is the quantity value of “most/often/usually”?
More than half. Potentially 100%
What is the quantity value of “several/many”?
More than 2. Potentially 100%
What is the quantity value of “some”?
At least 1. Potentially 100%
What is the quantity value of “few”?
At least 2, context dependent
What is the quantity value of “none”?
0
What are some examples of extreme language (and more likely to be wrong in inference questions)?
All, always, definitely, every, never, none, only
What are some examples of moderate language (and more likely to be correct in inference questions)?
Maybe, not all, not always, not every, perhaps, possibly, some, sometimes
What are two ways of evaluating an argument’s validity?
Invalid argument often:
1) overgeneralize based upon insufficient evidence (draw too strong a conclusion from weak evidence)
2) Fail to consider alternate causes/explanations/possibilities (assume potential cause is THE cause)
How does one identify a necessary assumption question?
“Assumption” with words such as “depends upon”, “requires”, “assumes”, “presupposes”
Eg “Which one of the following is an assumption upon which the argument depends?”
How does one identify a sufficient assumption question?
“Assumption” with words such as “allows”, “enables”, “follows logically/is properly inferred…if assumed”
How does one identify a strengthen question?
“Strengthen”, “most strongly supports”, “most justifies”, “most helps to justify”, “additional support”
Eg “which one of the following, if true, most helps to strengthen the argument?”
How does one identify a necessary weaken question?
“Weaken”, “call into question”, strongest logical counter”, “undermine”, “cast doubt”, “incomplete”
How does one identify a flaw question?
Words such as flaw, error, vulnerable to criticism, questionable, fallacious, unwarranted, weakness
Eg “The argument is vulnerable to criticisms on the grounds that if”
How does one identify an evaluate the argument question?
Eg “Which one of the following would be most useful to know in evaluating the argument?”
How does one identify a method of reasoning question?
Words such as “method of reasoning”, “argument proceeds by”, “responds…by”, “employs…strategies/techniques”
E.g. “The argument employs which of the following reasoning techniques?”
How does one identify an inference question?
Words such as “must be true”, “most strongly supported”, “cannot be true”, “logically follows”, “properly inferred”
Stem: “if the statements above are true, which one of the following must also be true?”
How does one identify a role of statement question?
Words such as “plays which one of the following roles”, “figures in the argument”
Stem: “the claim that inventors sometimes act as their own engineers plays which one of the following roles in the argument?”
How does one identify a parallel reasoning / parallel flaw question?
Words such as “most closely parallel to”, “most similar to”, “logical structure”, “pattern of reasoning”
Stem: “Which one if the following arguments is most similar in its reasoning to the arguments above?”
How does one identify a point at issue question?
2 people in stimulus with “disagree over” or “point at issue between”
Stem: “The dialogue lends the most support to the claim that Jenkins and Lurando disagree on whether…”
How does one identify a principle question?
Words such as “principle”, “proposition”
E.g “The reasoning in the argument most closely conforms to which one of the following principles?”
How does one identify a resolve the paradox question?
Words such as “helps to resolve/reconcile”, apparent/seeming paradox/discrepancy/inconsistency/contradiction”, “contributes to an explanation”
Stem: “Which one of the following, if true, most helps to resolve the apparent discrepancy above?”
How should a necessary assumption question be approached?
Negate each choice. The correct choice, when negated, destroys he argument’s validity.
How should a sufficient assumption question be approached?
Correct answer will guarantee conclusion’s validity by linking evidence with conclusion.
How should a strengthen question be approached?
Make conclusion more likely to be valid
How should a weaken question be approached?
Make conclusion less likely to be valid
How should a flaw question be approached?
Determine mistake in method of reasoning without looking at choices, then find description in choices
How should an evaluate the argument question be approached?
Determine what matters for the argument’s validity, what would strengthen/weaken if true or not
How should a method of reasoning question be approached?
Determine the type of evidence used to support the argument’s conclusion
How should an inference question be approached?
Look for connections in stimulus. If nothing jumps out in the answer choices, use process of elimination. If multiple conditionals are used, create a formal logic diagram.
How should a role of statement question be approached?
Identify parts of the argument in stimulus to determine how the statement fits in
How should a parallel reasoning/ parallel flaw question be approached?
Determine the method of reasoning or flaw in stimulus. Form abstracted version of method of reasoning, search for same in choices. If multiple conditionals, create a formal logic diagram
How should a point at issue question be approached?
Find answer choice which both people express opinions on, and expressed opinions are in opposition to each other (i.e. one person says yes, the other says no)
How should a principle question be approached?
Principle questions require you to find a parallel argument or strengthener. Either way, look for a generalized version of the argument that closely mirrors it
How should a resolve the paradox question be approached?
Look for answer choice that points out a way for everything in stimulus to be true at the same time
What are the 5 steps to solving Strengthen Logical Reasoning Questions?
1) Recognize that its a strengthen question
2) Look for the main flaw (if present)
3) Support the assumption and scan for answer choices that help patch up the argument
4) Remember new information can be presented in answer choice
5) Remember that “strengthen EXCEPT” = “does not strengthen”
What five rules should be kept in mind when approaching Weaken questions?
1) Recognize that it is a weaken question
2) Look for the main flaw if present
3) Attack the assumption and an for answer choice which exposes flaw
4) Answer choices may contain new info
5) Beware of “weaken EXCEPT” questions
How do you weaken a conditional conclusion?
Attack the necessary condition by showing that the necessary condition doesn’t need to occur in order for the sufficient condition to occur
What is the “Shell Game”?
When an idea or concept is raised in the stimulus, and then a very similar idea appears in the answer choice, but has been changed enough to be incorrect while remaining attractive
