David Horovitz , THE JERUSALEM POST A full half century after The Beatles began to take shape, Paul McCartney still sounds awed, modest and appreciative when discussing the lasting resonance of their music. Ahead of his Tel Aviv concert on Thursday, McCartney talks here to The Jerusalem Post about his beliefs, about how he copes with near-universal fame, about the puzzling, even "magical" inspiration for some of his songs, and about his abiding, insistently optimistic outlook on life. Paul McCartney, just turned 15, was introduced to John Lennon, all of 16, at a church fete in Woolton, Liverpool, at which Lennon's skiffle group, The Quarrymen, was playing. The older boy, so legend has it, was impressed by McCartney's familiarity with rock and roll music and his facility with a guitar. For one thing, he knew how to tune it properly. The year was 1957. McCartney, who had already started penning his own songs (he still sometimes plays his first ever composition, "...