Semantic properties are things that are true of something that have to do with meaning.

Some semantic properties:

• meaning (specific propositional contents)
• truth value (true or false)
• consistency
• entailment
• reference

Argument against reductive materialism:

1. If thoughts were brain states, then semantic properties would be true of brain states.
2. Semantic properties are not true of brain states.
3. Therefore, thoughts are not brain states. (1, 2: modus tollens)

Churchland's response: Deny premise 2.