Abstract
Internalism about mental content holds that microphysical duplicates must be mental duplicates full-stop. Anyone particle-for-particle indiscernible from someone who believes that Aristotle was wise, for instance, must share that same belief. Externalism instead contends that many perfectly ordinary propositional attitudes can be had only in certain sorts of physical, sociolinguistic, or historical context. To have a belief about Aristotle, for instance, a person must have been causally impacted in the right way by Aristotle himself (e.g., by hearing about him, or reading some of his works).An interesting third view, which I call