1. Entity Theories of Meaning

2. Meaning Talk Theory should make sense of meaning talk Theory should make sense of meaning talk What sorts of things do we say? What sorts of things do we say? Words and phrases mean things = have meanings Words and phrases mean things = have meanings Synonyms have the same meaning Synonyms have the same meaning Ambiguities have more than one meaning Ambiguities have more than one meaning Meaningless things have no meaning Meaningless things have no meaning Must there be meaning-things we can have? Must there be meaning-things we can have? Not necessarily, but let’s test the idea Not necessarily, but let’s test the idea

3. Are Meanings Ideas? Matches our intuitions Matches our intuitions What do you mean? = what do you have in mind? What do you mean? = what do you have in mind? To understand a meaning is to know what someone was thinking To understand a meaning is to know what someone was thinking Frege thought that a thought was the sense of a sentence (True or False was its reference) Frege thought that a thought was the sense of a sentence (True or False was its reference) Try this: For a term to have a meaning is for it to be associated properly with an idea Try this: For a term to have a meaning is for it to be associated properly with an idea

4. Are Meanings Ideas? What is an idea? What is an idea? Shifts the problem to Philosophy of Mind Shifts the problem to Philosophy of Mind That may be the right place for it That may be the right place for it But it doesn’t help us understand meaning But it doesn’t help us understand meaning

5. Are Meanings Ideas? Can this theory support compositionality? Can this theory support compositionality? Meaning of a sentence is the compositional result of the meaning of the parts of a sentence Meaning of a sentence is the compositional result of the meaning of the parts of a sentence The meanings of some sentence parts don’t seem to be ideas The meanings of some sentence parts don’t seem to be ideas ‘The pen is in my hand’ ‘The pen is in my hand’ What’s the idea for ‘in’ or ‘is’ or ‘the’? What’s the idea for ‘in’ or ‘is’ or ‘the’? Assume some parts of sentences just indicate how the composition is to be done Assume some parts of sentences just indicate how the composition is to be done

6. Are Meanings Ideas? Can we get intersubjectivity? Can we get intersubjectivity? We want ‘dog’ to mean the same for everyone We want ‘dog’ to mean the same for everyone But my idea of a dog is not the same as your idea (if only because it’s in my head not yours) But my idea of a dog is not the same as your idea (if only because it’s in my head not yours) Perhaps we’re interested in ideas as ‘types’ or ‘classes’ Perhaps we’re interested in ideas as ‘types’ or ‘classes’ Compare a linguist’s interest in sentences Compare a linguist’s interest in sentences But then these classes aren’t ideas but abstractions But then these classes aren’t ideas but abstractions

7. Propositions Take propositions to be whatever it is that makes two ideas (in sentences) the same idea Take propositions to be whatever it is that makes two ideas (in sentences) the same idea So my idea that Brisbane is the capital of QLD expresses the same proposition as your (different) idea that Brisbane is the capital of QLD So my idea that Brisbane is the capital of QLD expresses the same proposition as your (different) idea that Brisbane is the capital of QLD Try this: For a sentence to have a meaning is for it to be associated properly with a proposition Try this: For a sentence to have a meaning is for it to be associated properly with a proposition Still explains synonymy, ambiguity, meaninglessness, and intuitions about ideas in same way as idea theory Still explains synonymy, ambiguity, meaninglessness, and intuitions about ideas in same way as idea theory

8. Propositions Still allows compositionality Still allows compositionality The parts of a sentence are terms The parts of a sentence are terms The meanings of terms are concepts The meanings of terms are concepts The concept of dog is the meaning of the term ‘dog’ The concept of dog is the meaning of the term ‘dog’ Composition of concepts gives us propositions Composition of concepts gives us propositions Words such as ‘the’ ‘in’, … are guides to the composition of concepts Words such as ‘the’ ‘in’, … are guides to the composition of concepts

9. Propositions Still allows intersubjectivity Still allows intersubjectivity That’s according to the definition of concepts and propositions That’s according to the definition of concepts and propositions

10. Possible Worlds Still need to know what propositions are Still need to know what propositions are The common understanding is: The proposition expressed by a sentence is the set of possible worlds in which that sentence is true The common understanding is: The proposition expressed by a sentence is the set of possible worlds in which that sentence is true ‘The cat is on the mat’ is true in any possible world in which the cat is on the mat ‘The cat is on the mat’ is true in any possible world in which the cat is on the mat

11. Possible Worlds Compositionality Compositionality Turns out to be possible – if we treat composing operations as set-theoretical functions Turns out to be possible – if we treat composing operations as set-theoretical functions Simple examples are logical operations: Simple examples are logical operations: M(A or B) = M(A) union with M(B) M(A and B) = M(A) intersection with M(B) M(if A then B) = everything not in M(A), union with M(B) There are also ways to combine concept-equivalents But those ways are too complex to talk about here

12. Possible Worlds Intersubjectivity Intersubjectivity Propositions and concepts are sets of worlds and sets within those worlds Propositions and concepts are sets of worlds and sets within those worlds Sets are objective not subjective Sets are objective not subjective

13. Possible Worlds Structured propositions Structured propositions Ambiguity is explicable and synonymy Ambiguity is explicable and synonymy But consider: the set of worlds where 1+1+2 is true is the same set of worlds where 2+2=4 is true But consider: the set of worlds where 1+1+2 is true is the same set of worlds where 2+2=4 is true So 1+1+2 has the same meaning as 2+2=4 ? So 1+1+2 has the same meaning as 2+2=4 ? We need something else We need something else

14. Possible Worlds Structured propositions Structured propositions Solve that problem by including in propositions some structure Solve that problem by including in propositions some structure The meaning of a sentence is the intensional structure that determines the set of possible worlds in which the sentence is true >> This is like the ‘mode of presentation’ of the truth value (Frege’s sense)

15. Possible Worlds Ockham’s Razor Ockham’s Razor ‘Don’t multiply entities beyond necessity’ ‘Don’t multiply entities beyond necessity’ Do we really want these things in our picture of the world? Do we really want these things in our picture of the world? But they may be necessary But they may be necessary Gravity was a new entity but we accept it now because it is necessary Gravity was a new entity but we accept it now because it is necessary

16. Possible Worlds Causal Power Causal Power We use the meanings of sentences to make things happen We use the meanings of sentences to make things happen Can structures of sets of possible worlds have any causal effect in the one actual world? Can structures of sets of possible worlds have any causal effect in the one actual world? How can we become associated with structures? (We need to if we’re going to understand them.) How can we become associated with structures? (We need to if we’re going to understand them.)