Viewed syntagmatically, article-introduced nominal clusters have been judged either to refer to an already mentioned or to an already known referent or not so to refer. If they do so refer, such reference is either anaphoric or deictic, and it signals identifiedness. Bloomfield seems to equate definiteness with identifiedness. And Paul Christophersen implies that identifiedness is one component of familiarity, familiarity being the distinctive meaning he assigns to the definite article the, […]
Source: wiktionary
In this case, the relative clause who is not identified is predicted to be false, matching our intuitions. Summing up the analysis, predications of identifiedness and unidentifiedness are analyzed as relations between a discourse referent and the output file introduced by the description of content.
Source: wiktionary
Observers have asserted that the identifiedness of the miners, the little girl, and the balloonist makes us especially willing to help them. As an empirical matter, this assertion is unproved and probably mistaken. As a normative matter, it seems clear that the rights of people not to be harmed should not depend on the identifiedness of the people who will be harmed.
Source: wiktionary