---
name: philosophy-of-language
description: "Master philosophy of language - meaning, reference, truth, speech acts. Use for: semantics, pragmatics, meaning theory, reference. Triggers: 'meaning', 'reference', 'Frege', 'sense', 'Kripke', 'speech act', 'semantics', 'pragmatics', 'truth conditions', 'propositions', 'names', 'descriptions', 'rigid designator', 'natural kind', 'context', 'indexical'."
---

# Philosophy of Language Skill

Master the philosophical study of language: How do words mean? How does reference work? What is truth?

## Core Questions

| Question | Issue |
|----------|-------|
| How do words mean? | Theory of meaning |
| How do names refer? | Reference theory |
| What is truth? | Truth theories |
| What do we do with words? | Speech act theory |

---

## Theories of Meaning

### Frege: Sense and Reference

```
FREGEAN SEMANTICS
═════════════════

REFERENCE (Bedeutung)
├── What expression picks out
├── "Venus" refers to Venus
└── Compositional: Reference of whole from parts

SENSE (Sinn)
├── Mode of presentation
├── Cognitive significance
├── "Morning star" vs. "Evening star"
└── Same reference, different sense

WHY BOTH?
├── "Hesperus = Phosphorus" is informative
├── "Hesperus = Hesperus" is trivial
├── Same reference, different sense
└── Sense determines reference
```

### Russell: Descriptions

**The Problem**: "The present King of France is bald"
- No King of France exists
- What does the sentence mean?

**Russell's Analysis**:
```
"The F is G" =
∃x(Fx ∧ ∀y(Fy → y=x) ∧ Gx)

"There is exactly one F, and it is G"

Not a referring expression but a quantified claim
False (not meaningless) because no unique F exists
```

### Direct Reference

**Kripke's Revolution**:
- Names are rigid designators
- Refer to same thing in all possible worlds
- Not abbreviated descriptions

```
KRIPKE'S ARGUMENTS
══════════════════

MODAL ARGUMENT:
"Aristotle might not have been a philosopher"
├── Makes sense
├── But "The teacher of Alexander might not have taught Alexander"
│   └── Would make Aristotle not Aristotle
└── Names ≠ descriptions

EPISTEMIC ARGUMENT:
We can discover "Hesperus = Phosphorus"
├── A posteriori necessary truth
├── Same thing in all worlds
└── But discovered, not known a priori

SEMANTIC ARGUMENT:
Reference is causal-historical
├── Not by fitting description
├── Baptism + chain of communication
└── Name-using practice
```

---

## Meaning and Use

### Wittgenstein: Meaning as Use

**Early**: Meaning is picturing reality
**Later**: "Meaning is use in a language game"

**Language Games**:
- Meaning depends on context, rules, practice
- No single essence to "meaning"
- Family resemblance

**Private Language Argument**:
- No purely private meanings
- Rule-following requires community
- Meaning is public

### Speech Act Theory (Austin, Searle)

```
SPEECH ACT THEORY
═════════════════

THREE TYPES OF ACTS:

LOCUTIONARY
├── Saying something with meaning
└── Uttering words with sense and reference

ILLOCUTIONARY
├── What you do in saying it
├── Promising, warning, asserting
└── Force of the utterance

PERLOCUTIONARY
├── Effect on hearer
├── Persuading, frightening, amusing
└── Consequences of saying

FELICITY CONDITIONS:
├── Preparatory: Appropriate circumstances
├── Sincerity: Speaker means it
├── Essential: Counts as the act
└── Infelicity: Act fails (not false, but unhappy)
```

---

## Reference and Names

### Descriptivist Theory

**Frege/Russell**: Names = disguised descriptions
- "Aristotle" = "The teacher of Alexander" (or cluster)
- Reference determined by satisfying description

**Problems** (Kripke):
- Modal: Could have failed to satisfy description
- Epistemic: Can discover identity
- Semantic: Reference even with false beliefs

### Causal-Historical Theory

**Kripke/Putnam**:
- Initial baptism fixes reference
- Reference transmitted through causal chain
- Community-based reference

### Natural Kind Terms

**Putnam's Twin Earth**:
```
TWIN EARTH
══════════

Scenario:
├── Twin Earth exactly like Earth
├── Except "water" is XYZ, not H₂O
├── XYZ phenomenally identical to H₂O
└── 1750: No one knows difference

Question: Does "water" mean the same?

Putnam: No!
├── "Water" on Earth refers to H₂O
├── "Water" on Twin Earth refers to XYZ
├── "Meanings ain't in the head"
└── Natural kind terms refer to natural kinds
```

---

## Truth

### Correspondence Theory

- Truth = correspondence to facts
- "Snow is white" is true iff snow is white
- Problems: What are facts? What is correspondence?

### Coherence Theory

- Truth = coherence with other beliefs
- System of beliefs that hangs together
- Problems: Coherent fictions?

### Pragmatic Theory

- Truth = what works
- Useful beliefs are true
- Problems: Useful ≠ true

### Deflationism

- "True" is just a device for endorsement
- "Snow is white" is true = Snow is white
- No substantial property

### Tarski's Semantic Theory

```
TARSKIAN TRUTH
══════════════

T-SCHEMA:
"S" is true iff S

EXAMPLE:
"Snow is white" is true iff snow is white

Requirements:
├── Object language (mentioned)
├── Metalanguage (used)
├── Hierarchy avoids liar paradox
└── Truth defined for formal languages
```

---

## Context and Indexicals

### Indexicals

- "I", "here", "now", "this"
- Reference depends on context of utterance
- Kaplan: Character vs. Content

```
KAPLAN'S THEORY
═══════════════

CHARACTER
├── Rule for determining reference
├── "I" = speaker of context
└── Constant across contexts

CONTENT
├── What's said in context
├── "I am tired" said by me
└── Proposition about me
```

### Contextualism

- Meaning of many expressions context-dependent
- Not just indexicals
- "Knows", "tall", "ready"

---

## Key Vocabulary

| Term | Meaning |
|------|---------|
| Sense | Mode of presentation |
| Reference | What expression picks out |
| Rigid designator | Same reference in all worlds |
| Indexical | Context-dependent expression |
| Proposition | What is said, content |
| Speech act | Action performed in speaking |
| Illocutionary force | Type of speech act |
| Compositionality | Meaning of whole from parts |
| Use theory | Meaning is use |
| Direct reference | Names refer without sense |

---

## Integration with Repository

### Related Skills
- `analytic-philosophy`: Core tradition
- `logic`: Formal semantics

### Related Themes
- `thoughts/knowledge/`: Language and thought