How long could we remain true to the girls? How long could we keep their memory pure? As it was, we didn't know them any longer, and their new habits-of opening a window, for instance, to throw out a wadded paper towel-made us wonder if we had ever really known them, or if our vigilance had been only the fingerprinting of phantoms.
The passage reflects on the struggle to maintain the memory of a group of girls, questioning the authenticity of their recollections. It emphasizes a sense of uncertainty about how well they really knew the girls, especially as their behaviors changed over time, leading to doubt about the true essence of their identities.
This contemplation reveals a deep emotional conflict between nostalgia and the reality of change. The act of simple tasks, like throwing out a wadded paper towel, symbolizes the distance growing between the observers and the girls, suggesting that what they once remembered may now be distorted by time and new habits.
