This song is mainly about life and death, creation and destruction. Since he was still pained by his mother's death, and wrote songs in both Boy and October about it, some of his inspiration was probably from that. The line ".... the streets look so bear, of all they wear, do I care?" also shows that he was wondering whether people should even pay attention to the deaths of other people, even friends and family. He's mainly saying that people are born and die every day, and although it's good to care about them, we need to get over them if we can.
Paul Tripp, paultriphome.net ( 5:th of February 1999)
This song October, I believe, is about Bono looking back at the death of his mother. He's not caring about anything going on around him (...and the trees are stripped bare of all they wear. Do I care?). The pain of his mother's death remains and he can't let go of it (...but you go on...and on...).
As for the music...supposedly, when Edge wrote the song, he saw it as a sort of soundtrack for an unwritten movie.
Alexandra Martin shinmaangelfire.com (20:th of February 1999)
The other explanations are only partially correct. According to an interview from 1982 October is actually about the Bolsheviek revolution in Russia in 1917, that brought Communism to power. October, Kingdoms rise and Kingdoms fall. This theme is mixed with a personal theme, possibly his mothers death but you go on, and on.
Laurence Dunne codeguy1yahoo.com (16:th of October 2001)