Semantics Flashcards
(40 cards)
Predicates
semantic category, distinct from syntactic categories like adjective etc.
picks out a set of objects with the property in question: a chair denotes the property of being a chair, happy denotes the property of being happy etc.
Referring Expressions
picks out a specific, salient individual (eg, proper names)
argument of the predicate
Individual
relates to any object you wish to refer to (yourself, your feet, the chair you’re sitting on)
Proposition
combine a subject (referring expression) with a predicate to yield a proposition
roughly, a sentence meaning
can be true or false
is/was
syntactic glue
Truth Conditions
a proposition can be true or false in a given situation.
recipe for finding out the truth conditions -
‘Barack Obama is very happy’ is true iff the individual denoted by ‘Barack Obama’ is in the set of very happy things at the time in question.
iff
if and only if
1-Place Predicate
verb takes just one argument (subject)
2-Place Predicate
3-Place Predicate
involves 2 individuals
involves 3 individuals
4-Place Predicate
syntactically a ditransitive verb but there is a difference between this and a 3-place predicate in semantics
involves 4 individuals:
[SHE] bet [ME] [THIS AMOUNT] [THAT…]
Propositional Attitudes
predicates that describe the way that individuals relate to propositions (believe, doubt, hope, consider)
“They believe that the Earth is flat”
- believe takes 2 arguments: an individual (they) and a proposition (the Earth is flat)
Recursion
can have attitudes about people’s attitudes
= recursion of propositional attitudes
Using Logic to Refer to Individuals
constants: using a single lower-case letter
London is denoted by ‘l’
Obama is denoted by ‘o’
variables: using x, y, z
Variable Individuals
meaning changes - denote different variables at different times
Using Logic to Refer to Predicates
Dog denotes a set of individuals that the have the property of being dogs.
{x : x is a dog}
property of individuals, denoted by x
{} - refers to set
Using Logic to Refer to Propositions
- propositions either denote true or false.
- if a proposition is formed from an individual and a set, the proposition denotes T or F iff the individual is in the set.
- ‘Dog’ could denote a function mapping individuals in the set of dogs to T, and others to F (function dog’)
Fido denotes f
cat denotes cat’
Fido is a cat denotes cat’(f)
(T iff f is in {x: x is a cat}
Using Logic to Refer to N-Place Predicates
a 1-place predicate is true or false of an individual; an n-place predicate is true or false of a list of individuals
- denotes sets of individuals
Love denotes { : x loves y} etc.
<> = list
Fido loves Butch denotes love’(f,b)
T iff ∈ {x,y : x loves y}
Fido gave Butch to Obama denotes give’(f,b,o)
T iff ∈ {x,y,z : x gave y to z}
Using Logic to Refer to Propositional Connectives
for propositions P and Q
P & Q is true iff P is true and Q is true
P ∨ Q is true if at least one of P and Q is true (P or Q)
~P is true iff P is false (negation of P)
P -> Q is true unless P is true and Q is false (if P then Q)
Using Logic to Refer to Propositions as Arguments
for now:
Believe denotes { : x believes that y}
A ⊂ B, B ⊃ A
A is a proper subset of B; B is a proper superset of A (every member of A is also a member of B; at least one member of B is also a member of A)
A ⊆ B
A is a subset of B (but also allows the possibility that A = B)
|A| = 2
A contains 2 members (cardinality of A)
|A| > |B|
A contains more members than B
x ∈ A
x is a member of the set of A