This song is based on Sonnet 18 by William Shakespeare. Dan revealed this long ago on his twitter. The song goes along the line of loving someone to the point of obsession, but saying the words out love won't make them last forever. If he were to write down how he feels and express his love through poems or letters, it will live on forever as long as people are still around to read - 'In eyes not yet created, On tongues that are not born, I have written you down, Now you will live forever'. Very beautiful song, my favourite