Once upon a time we played songs.  These songs had names.  Eventually, we became to lazy to call the songs by their names, and started referencing them as the number in the sequence which they were created  Song 1, song 5 etc.  Then we stopped feeling obligated to have singers, or "lyrics",  so gone were the song names, simply because the "songs" had no lyrics to derive a name from.  Then we stopped playing songs altogether.  We just played.  And play on we did....