"Dialogue" is a two-part song on Chicago's album Chicago V. It was written by Chicago founder Robert Lamm. The song takes the form of a debate of sorts, with two characters discussing the state of the world and all the troubles in it in 1972, with opposite roles taken by vocalists Terry Kath and Peter Cetera. It is a very sophisticated song; the two characters have differing philosophies. Terry repeatedly asks Peter if he's worried about issues such as the war (the Vietnam one in this case) and poverty. Peter responds in the negative, saying that basically he doesn't worry about these things too much and it doesn't bother him.
However, if you listen closely, Peter closes out his part by saying, "If you had my outlook, your feelings would be numb; you'd always think that everything was fine." In other words, Peter is being portrayed as having his head in the sand and being indifferent to the world's problems. Nevertheless, part two closes on an optimistic note, but one of a call to action to make things work out. Furthermore the second part has an abrupt stop, leaving you with your thoughts. Think of this tune the next time you hear modern complaints of the polarization of United States society!
Now listen to it again and notice the instrumentals - Peter and Terry's bass and guitar are also having a dialog, a feat all the more remarkable for Lamm, normally a keyboardist, having written the music as well.