The Pope - for the first time ever - addressed a radio audience today in Britain, on the BBC - and his message was both warm and classically Christian. His message was canonical: the Christ child entered the historical world, not as a conquering saviour, but a fragile, suffering human being, liberating the human condition in subtle, surprising ways. The complexity of the Christmas message is in its paradoxes - which have made Christianity so endlessly attractive to artists and writers - for its ironies and ambiguities allow for rich and continuous rejuvenation. But, it also has a simple core, which is love. Rather, love and forgiveness, for the two are not quite the same. This Christmas message is often symbolised, in a secular way, as Santa Claus , that great outrider of Christian humanism. Santa, who cannot be faulted, gives of himself each year for little children, showering them with gifts (if the kids have been well-behaved); the rest of the year, the childless man with hi