Any God fearer is going to be a little nervous about a song that uses the phrase "God only knows what I'd be without you" over and over, especially when this has become a meaningless cliché for most. Lyricist Tony Asher was aware that God's name did not usually appear in a pop song. He and fellow composer Brian Wilson were really not sure whether the use of the word would deny them airplay. It did not. (The Beach Boys had already recorded a version of the Lord's Prayer three years earlier but that is different and time had moved on. Here the idea of God is apparently not a particularly Christian one). If the phrase is taken at face value, there certainly is a mystery for most couples, known only to God, when they contemplate life without their partner, whether that is due to death or some other unforeseen circumstance. It has been claimed that the song (released first on the legendary album Pet Sounds) heralded the reinvention of the love song and that may be the case. Asher's lyrics (I may not always love you But long as there are stars above you You never need to doubt it I'll make you so sure about it) are certainly above the average pop song (Why do fools fall in love? Why do birds sing so gay? And lovers await the break of day Why do they fall in love?). The song is sung by Carl Wilson and has very much a Beach Boys sound, though the instrumentation is very forward looking - using French horns, accordions, sleigh bells, harpsichord, etc (played by 16-23 different musicians) and a string quartet dubbed on later. The musical structure has often been cited for its harmonic complexity, its rejection of authentic cadences and a definite key signature. Its closing section features perpetual rounds, unusual in pop music at the time. There is something very baroque about it.
