What It Is
"The first problem one encounters by trying to decipher what Greg was trying to say in this song is what 'it' is. It's used all over, but Greg never says what 'it' really means. 'It' continuously changes meanings, so it's hard to define. The songs talk about the meaning of life, in general, but that this 'it' (the meaning) is unknown. He says, 'there's a purpose, there's a goal . . . there's a reason for all of this . . . there's a beginning and there's an end, there's a climax.' All is trying to explain why humans are here, why there's life, it's kind of religious (but we know Greg's position towards religion, so I wouldn't consider that strongly). By there's a 'climax,' Greg means that there's a stage in your life when you're either in the best or worst position, when one move will determine your whole life. There's a beginning to life, then the climax comes, and finally there's an end--death. There might be a reason for all the suffering and pain and rewards in life, but Greg simply can't describe what this 'it' is. No one can, and that's why this song is tough to define."
"I think it might be the same (ubiquitous) thing throughout the song. Could it be life, our existence? Striving for some meaning in this life? Trying to find out if/what's the reason for all of this?"