Exam 2 Flashcards
Premises and conclusions make what?
Arguments
Draws out the logical implications of a set of premises.
Deduction
Sound arguments guarantee to have what?
True conclusion
A statement that can be true or false.
Proposition
A&B is true if and only if both A and B are both true.
Conjunction
A v B is true if and only if A or B or both are true.
Disjunction
-A is true if and only if A is false.
Negation
A&-A are always false since they encompass statements that are inconsistent that can’t both be true.
Contradiction
Av-A always true hence uninformative
Tautology
You want to get married but you also don’t want to get married. What proposition is this?
Contradiction
Saying someone is a Bachelor is the same as saying they are not married. What proposition is this?
Tautology
I will clean the kitchen, if Mary helps me. If Mary helps me, I will clean the kitchen. What conditional reasoning?
Bi-conditional
X implies Y, and Y implies X. What conditional reasoning?
Bi-conditional
X; If X, then Y; Therefore Y. What conditional reasoning?
Modus ponens
-Y; If X, then Y; Therefore -X What conditional?
Modus tollens
If X, then Y; If Y, then Z; Therefore, if X, then Z. What conditional?
Hypothetical syllogism
Y; If X, then Y; Therefore X. What conditional error?
Affirming the consequent
-X; If X, then Y; Therefore -Y.
Denying the antecedent
Weed eater-Yard-House-Family-Wife-Heterosexual. Not weed eater-Not heterosexual. What conditional error?
Denying the antecedent
Condition is supported by two premises, major and minor.
Syllogism
One or more premises are left unstated.
Enthymemes
X or Y or Z; Not X; Not Y; Therefore, Z.
Disjunctive syllogism
Prove that X is true by showing that its opposite, -X, is false or leads to a contradiction.
Reductio ad absurdum
- Trump is leading in the polls. 2. Leading polls, then Republican nominee. 3. Trump will be Republican nominee. Not true depends when polls were taken.
Enthymemes