Tim O'Brien's story talks about dualistic thinking, sets of opposites. We see rational as one side and irrational on the other side. Truth vs. fiction. The story breaks down all the sets of opposites. Mary Anne crosses these borders in one way or another. She crosses over from female to male. She crosses the border from sanity to insanity. She does this because she had a desire for knowledge and a curiosity. She immerses herself in this world of Greenies. "She fell into a restless gloom, sitting off by herself at the edge of the perimeter. She would not speak. Shoulders hunched, her blue eyes opaque, she seemed to disappear inside herself."