'I'd like to teach the world to sing, in perfect harmony.' So sang The New Seekers back in the 70s with their song of hope and peace, of universal love, trust and forgiveness, and strangers stopping to smile at one another in the street. It became an enormous hit, not just because the tune was so catchy but because the sentiment struck such a chord. We wanted it then, we still secretly want it now. We might yet get it. But not by chasing rainbows indiscriminately. Some dreams today are probably best kept in dreamland.