a commonplace book
Languages are conservative, they always carry their archives with them and hate having to be updated.
José Saramago, Seeing (2006)
The aphorism takes a subordinate, dual-part form: equivalent statement (A = B; metaphor) -> expository statement, with the weight on the second of two clauses, the first being independent, the second dependent.
The sentence establishes a hierarchical rhetoric of authority: Each successive clause stems from the one before it, but the first stands autonomous. It is no mean authority that separates two big words with a mere copula and remains standing.