Logical Reasoning Flashcards
Logical Reasoning Method
1) identify question type
2) untangle the stimulus
3) make a PREDICTION
4) evaluate answer choices
Common Logical Reasoning Wrong Answer Types
- 180
- outside the scope
- faulty use of detail
- distortion
- half wrong/half right
- extreme
- irrelevant comparison
One Sentence Test
“if author had to boil this entire argument down to one sentence that retains his main point, which sentence would it be?”
Assumption
to ID: assumed, assumption, presuppose, if added to the premises
task: bridge the gap between the evidence and conclusion
Denial Test
an assumption MUST be true for the conclusion to logically follow from evidencedenial test: negate each answer choice to find one where author’s argument falls apart. the one that does is a necessary assumption. don’t be extreme when negating (denial of hot is not cold it’s NOT HOT)when denying if/then, negate “then” or the result if argument does not fall apart or is unaffected after negation, the answer choice is wrong.
Strengthen/Weaken
to ID: strengthen, most strongly supports the author, most weakens, calls into question, undermines
task: find the answer that makes the conclusion more/less likely to follow from the evidence
Common Flaws
- confusing correlation with causation- confusing percent and actual value- unsupportable scope shifts between evidence and conclusion- overlooked alternatives (most common)- inappropriate combination or distinction of terms (flaw of equivocation)ALL flaws center on author’s assumption
Flaw
to ID: vulnerable to criticism, questionable, error of reasoning, describes a flaw
task: find disconnects between evidence and conclusion and identity classic flaws
Representativeness
any argument based on a group or sample (from surveys, polls, studies, anecdotes, or experiments)needs to be a good representation - come from large enough sample, cover an adequate amount of time, population can’t be biasedASSUME sample is representativecompare population of the evidence with that of conculsion
Inference
to ID: must be true, logically completes the passage, can be inferred, which of the following is most strongly supported
task: determine what MUST be true; look for connections
P/P/P
an argument’s conclusion is a plan, prediction, or proposalASSUME that P/P/P could work or happen, practical under circumstance, there is only one most important factor (or only 1 factor) worth consideringto weaken: introduce alternative or competing consideration (plan won’t work) - raise concern author fail to see that would undermine proposal to weaken prediction: show that trend will change or is unlikely to happento weaken an objection to a P/P/P: seek evidence that it will work or come truelook for: should, would, could, may, will, is going to
Parallel Reasoning
to ID: parallel to, similar to
task: compare part, or all, of the stimulus to the choices
Causality
cause and effectany argument that says something did or will happen because of something elsex caused y or y is a result of x relies on assumptions:that nothing else caused y but xthat y was not the cause of xthat the apparent relationship between x and y is not just a coincidenceto recognize: if/then, because, correlate, cause, as a resultto weaken: alternative explanation (z caused y, not x), , causality reversed (y caused x), coincidence (it wasn’t x that caused y, no correlation between x and y)
Method of Argument
to ID: responds to…by, the argument proceeds by, argumentative strategy
task: paraphrase the argument into abstract terms
Assumption
unstated evidence necessary to make argument work/bridges gap between evidence and conclusion (sometimes evidence and evidence)author MUST believe!evidence + assumption = conclusion
