Cassin’s Dictionary makes translation itself the organising problem of a philosophical lexicon. Its “untranslatables” are not words that cannot be translated at all, but terms whose movement between languages remains unfinished, unstable or repeatedly subject to mistranslation and retranslation. The preface places the project within a genealogy that includes encyclopaedias, philosophical vocabularies, Williams’s Keywords and Koselleck’s conceptual history, while also describing translation as rewriting: translators become contributors because lexical transfer alters the object. The methodological operation is productive non-equivalence. Instead of standardising different linguistic histories into a single conceptual token, the Dictionary preserves the disturbances produced by polis, Begriff, praxis, Aufheben and comparable terms. This bridges philosophy, translation studies, comparative literature and conceptual history. Its importance to machine-readable lexica is exact: interoperability cannot be equated with synonymy. Alternate labels, language tags and mappings require an architecture capable of carrying unresolved difference. A concept can be addressable across languages without becoming semantically interchangeable.
