I believe this song is about how the human race keeps going in the same direction.(i.e. wars,famine,poverty) The line "On the ignorant plenty who devote their lives to an icon that they've never known" is his way of saying he shows pitty for people who put all thier faith and all thier effort into a supernatural being they have never even meant. I think hes trying to say to live for yourself. Also, the line "When early man started the first civilization and human aggression was born" means that ever since the early days of mankind we have fought countless wars based on beliefs and religion. He shows pity on "the billions of ignorant people" meaning all the people that dont think for themselves and allow things such as religion and race divide the human race. "On the future centuries to come" meaning he believes that we will always head in the same direction unless we can start questioning things like religion and war. Thats my take on this song and I hope to hear more comments on it in the future.

i'd like to tell you something that this song reminds me..
in my country, we had the most disastrous dictatorship in the 70's, full of murders and tortures and much more... and after that, in the 90's, ten years of corruption and impunity with our "dear president Menem" (best friends with george bush father)... funny right?..
i grow up in that decade, being an idiot... with an ignorant society... who tried everyday to make me feel like part of it, when I wasnt.. thank god i have a great family who tought me how to live this life... i took advice from them and I learnt how bad is our world right now!... sometimes I wonder if we're heading for something... sometimes i want to believe that we will have a future... but it's hard to trust on that, when the present day is this already messed up. One last thing..
don't let them manipulate you..