In line four, the speaker says that our eyes "vainly crave the light." this is an example of symbolism. what does "light" refer to here?

in the quotation from passage, connie willis states that literature is a way for authors from the past to communicate with readers of today. we can read their stories, books, and other texts to learn lessons about life. willis refers to these lessons as messages “from beyond the grave.” willis has a favorable viewpoint about the timelessness of literature.