In the moth, Virginia Woolf sees a metaphor for life; it works hard to survive and eventually dies. She sees that as representative of the purpose of human life.
As often as he crossed the pane, I could fancy that a thread of vital light became visible. He was little or nothing but life.
Even though the moth is small and not very expressive, she still sees in its small existence a piece of life. She sees how hard it fights against giving into death. She looks back at it after a while and sees that it is struggling to move and stay alive, even though it can no longer move gracefully. Like humans, it wants to stay alive. It's trying not to die.
Woolf says she knows that nothing has a chance against death. Everything is definitely going to die. But still the moth struggles to keep its spark from going out....
(The entire section contains 2 answers and 456 words.)