This thesis investigates the nature of the relation between mental representations in successful verbal communication, thought attribution, agreement, and disagreement — a relation which I call “samethinking”. The nature of samethinking raises several foundational questions about the nature of (non-natural) meaning, and the cognitive underpinnings of the emergence of culture. It bears on long-lasting puzzles in the philosophy of mind and language (such as Frege’s puzzle and Kripke’s puzzle about belief). Samethinking does not amount to sharing a reference (with “sharing" (...) I refer to two or more thinkers having something in common): it is more demanding. How can we explain and characterize this relation, more stringent than coreference, that is instantiated by a pair of thoughts when samethinking takes place? It is often assumed that this relation involves sharing a thought content more fine-grained than reference. In this thesis, I argue that the issue is more complex than what has been commonly assumed, and I suggest an alternative model in which sharing thought content is not necessary. (shrink)