Logic exam 3

truth value

the determination of a statement or proposition as either true (T) or false (F)

• undetermined is not a truth value

quantity of a categorical preposition

• universal (All or none)

• particular (some)

quality of a categorical preposition

• affirmative

• negative

contradiction

• two propositions contradict if and only if they have opposite truth values - if one is true the other is false (vice versa)

contrariety

two propositions if and only if they cannot both be true but might be false (U)

subcontrariety

cannot both be false, but might both be true (U)

subalternation

top to bottom (T) otherwise (U)

superalternation

bottom to top (F) otherwise (U)

distribution

a term is distributed if and only if we know with certainty that we are talking about all members of a class

deductively valid argument

if the premises all are true, the conclusion must be true

existential import

referring to things that exist in space and time - statement that cannot be true unless its subject term refers to one or more actually existing things

In venn diagrams what does x mean?

at least one member class is not empty

• used for I and O prepositions (some)

In venn diagrams what does it mean to shade the area?

no members class is empty

• used for A and E prepositions (all or none)