It`s an unusual song,it`s mostly instrumental and just that one verse.I think it`s one of the best songs J ever did.If it is about society,the doubt of living in this era and where we`re going in the future.We live in a world of hatred,war,dishonesty,greed,etc but of course that has always been here since the dawn of man.The lung might be a metaphor for society and the doubt we all feel everyday.
That`s the best I can think up about it.