Decoud? Or Conrad himself? The next paragraph addresses the latter possibility. Of course, if the "sincere passion" was Conrad's desire to create the novel (which contains the Occidental Republic), and that passion was inspired by Antonia, then Antonia is surely the creator of the Occidental Republic! A circular logic not unlike the conceit of the Author's Note. However, inasmuch Antonia represents idealism, there may be a kind of truth to it. An idealistic purpose is required even to create a work as deeply anti-idealistic as Nostromo.