Reasoning Flashcards
Implication Family
Take stimulus as true (MBT, SMBT, MBF)
Operations Family
Take answer choices as true, will affect the stimulus (Strengthen, weaken, crux, resolve, explain)
Characterization Family
Describe some element of the stimulus (main point, how conclusion is reached, disagreement, flaw)
Propositions
Declarative statements that are either true for false. Sentences can have 1 or more propositions
Arguments
A proposition (conclusion) supported by other (premises)
Conclusion Indicator Words
Thus, therefore, so hence, as a result, consequently, it follows that, accordingly, clearly
Premise indicators
since, because, for, after all, given that
Assumption
Must be true for the conclusion to be be proven by the premises, but wasn’t stated in the argument
Logical Validity
Valid: Conclusion must be true based on the premises
Invalid: Truth of premises doesn’t guarantee truth of conclusion
Reasoning Steps
- Identify conclusion and premisses
- Evaluate validity of argument
- If invalid, spot assumptions/mistakes
Absolute Statement
Asserts a concrete fact: John is a Dr.
Conditional statement
Hypothetical Relationship (If…Then)
Necessary Condition
Required for event to occur, but does not guarantee it will
ie: If you’re a Dr. then you like people - liking people is necessary, just because you like people, doesn’t mean you’re a dr.
Sufficient Condition
If present, the event will occur, but the event could still occur without the SC
ie: If you’re a Dr. then you like people. - The dr. is the sufficient condition because being a dr. means you do like people
Valid Inferences
- Affirmation: SC allows us to conclude NC (Dr -> Like People)
- Contrapositives: Negate & Reverse (Don’t Like People -> Not Dr.)
Invalid Inferences
- Converse: Reversing SC and NC (Like People -> Dr.)
- Inverse: Negating both conditions (If Not Dr. -> Don’t Like People)
Sufficient Condition Indicator Words
If, when, all, every, each, the only, if and only if
Necessary Condition Indicator Words
Only if, only, unless, without, until, except, no, none, depends, needs, must, essential, requires
Transitive Property
When you can make connections between two conditions in statements with multiple conditions. The NC of one statement must match the SC of another statement (Remember contrapositive)
ie: If Kids have phones -> short attention spans. If Short attention spans -> like tv more than books.
Can be concluded if Kids have phones -> like tv more than books.
Steps for conditional statements
- Diagram statements - also diagram CP if needed
- See if the transitive property can be applied
- Guess the best answer before looking at answer choices
Logical Force
How weak or strong a proposition is - focus on small, easily overlooked words, rather than the big intimidating ones.
2 Types: Modality, Quantification
Modality
Degree of necessity expressed by a proposition - how certain it is something will occur (weak, moderate, strong)
Weak Modality
More than 0% (possibility)
Support weak conclusion - easiest to support
KW: may, could, might, can, occasionally
Moderate Modality
More than 50% (probability)
Support moderate/weak conclusion
KW: probably, likely, usually
Strong Modality
100% chance (necessity)
Supports all types of conclusions
KW: will, must, definitely, is/are
Quantification
Proportion of a group w/ a given property - how many things have a certain quality (weak, moderate, strong)
Weak Quantification
At least 1 (possibility)
KW: some, a few, several, many, a significant number, occasionally
Moderate Quantification
More than 1/2 (probability)
KW: most, majority, over 1/2
Strong Quantification
100% (necessity)
KW: all, any, each, every, the best
Most vs. The Most
Most - absolute claim over 50%
The most - comparative claim
Must Be True (Implication)
Presents statements and asks what must be true (aka supply a conclusion)
Tips: make no assumptions, no outside info, accept stimulus as true,
