"Man is tiny"
"But the world itself is only a speck of dust. And man is tiny--helpless!"...
"Nonsense. The earth is as old as we are, no older. How could it be older? Nothing exists except through human consciousness." (Orwell 265)
In my horror and suspense class today, we were talking about H.P. Lovecraft's "The Call of Cthulhu," and in that story the first thing he does is humble humanity by explaining just how utterly helpless we are to stand against the universe and its infinite dangers and mysteries. But in the Party's perspective, it is only that which humanity acknowledges that can do harm.
I tend to disagree with O'Brien. Just because you refuse to acknowledge the existence of something doesn't mean it can't affect you. We are constantly at the mercy of the forces of nature, as well as the forces of the civilized world that surround us. People can die in an instant in a freak accident in a lot of places, or have their lives destroyed by neutral forces that are simply beyond their control (take the events in New Orleans, for instance).
Life seems like a game of chance--at least, on the surface. But if you look a little deeper, sometimes you can see patterns of behavior or occurence, and I think it's seeing these patterns that leads people to the false conclusion that just by anticipating what will happen next, they can change their fate. We lose our respect for the chaos around us, constantly trying to bring order to it, and while it can work to a certain degree, there will always be things that we can't change.