In a closed question to a related topic on this forum, the following was suggested as an answer:
"Another is to use a proper noun as an example of particular traits that could also be held by others (a type of synecdoche). "The next Bob Dylan" (a singer-songwriter from the folk scene who will repeat Dylan's success), "He's an Einstein" (he's very smart), "All Mozarts have their Salieris" (not really true even for Mozart and Salieri, but let's say we believed the film Amadeus was accurate)"
I just want to ask when to use a/an and when to use the in the above-mentioned context (of using articles before proper nouns of person). Do an Einstein and the Einstein mean two different things?