 Second, information that is sufficient for identificational purposes (internally distinguishing one bearer of a name from another) may yet be inadequate to determine the extension of a name (Strawson 1959: 20–21). For instance, “the Roman author” is enough to distinguish Marcus Tullius Cicero from Cicero, Illinois (the two Ciceros some agent happens to know about). But it is not sufficient to select a unique Cicero in the world (Kripke 1980: 81; Donnellan 1970: 343). There is, for instance, Cicero’s younger brother, Quintus Tullius Cicero, also an author of several works.