The "world" is basically the life of the hypothetical singer, as his life is his whole world, and he's going to "tear the whole world down" because he's "tired" of being a failure. The "failure" at the end of the chorus is like him saying it to himself, "You are a failure." He's looking for the "light" that leads him "home", most likely his hope for him to return to the place of light from which he was created, his home.
Pretty sure this song is about suicide.
The "world" is basically the life of the hypothetical singer, as his life is his whole world, and he's going to "tear the whole world down" because he's "tired" of being a failure. The "failure" at the end of the chorus is like him saying it to himself, "You are a failure." He's looking for the "light" that leads him "home", most likely his hope for him to return to the place of light from which he was created, his home.