“Carrère has managed to renovate the idea of what nonfiction writing can be. Profoundly intimate, historically and philosophically serious but able to cast compulsive narrative spells, Carrère’s books are hybrids, marrying deep reporting to scholarly explorations of theology, philosophy, psychology, personal history and historiography.”
“I follow the question instead of trying to follow my own answer, even if it means I can’t formulate any clear theory.”
“What’s notable here is that regular people first noticed the melodic similarity and if not for the internet, it may well have gone uncredited or unnoticed.”
Here is one of those regular people, a musician singing the two songs over the same chords:
As you listen notice that the similarity is rhythmic as well as melodic: specifically, how the vocal phrases in both songs stretch over the barline and end beat one of the next.