Continuing with wikipedia: The story:
The daughters of Mne Seraphim are all shepherdesses in the Vales of Har, apart from the youngest, Thel. She spends her time wandering on her own, trying to find the answer to the question that torments her: why does the springtime of life inevitably fade so that all things must end? She meets the Lily of the Valley who tries to comfort her. When Thel remains uncomforted, the Lily sends her on to ask the Cloud. The Cloud explains that he is part of a natural process and, although he sometimes disappears, he is never gone forever. Thel replies that she is not like the Cloud and when she disappears she will not return. So the Cloud suggests asking the same question of the Worm. The Worm is still a child and cannot answer. Instead it is the Worm’s mother, the Clod of Clay, who answers. The Clod explains that we do not live for ourselves, but for others. She invites Thel to enter into her underground realm and see the dark prison of the dead where Thel herself will one day reside. However, Thel is assailed by mysterious voices asking a whole series of yet more terrible questions about existence. Uttering a shriek, she flees back to her home in the Vales of Har. The pit represents sex and mortality of life, while the Vales of Har represent virginity and eternity. The first part of the poem shows the good part of life as in Songs of Innocence whereas the concluding part shows that life is full of sorrows where smiles are never seen, as in Songs of Experience.The question is "Why the physical senses darken the soul by excluding it from the wisdom and joy of eternity?".Thel is the allegory of the unborn spirit who has gathered experience from her own discoveries and has decided to remain forever innocent.In The Book of Thel, the Vales of Har are depicted as an edenic paradise that lived in harmony; a world where the rain feeds the flowers and the clod of clay feeds the infantile worm.[15] The common belief in this world among the characters is that “everything that lives Lives not alone nor for itself.” Thel wishes to enter the world of experience and leave behind her innocent paradise. However, once Thel enters the world of experience, she cowers in terror at the thought of mortality and the uselessness of human beings if every action leads toward the grave. This can also be interpreted as Thel’s fear of losing innocence and virginity upon entering the world of adult sexuality. In other words, Thel’s fear of growing up is what keeps her from actually living. When she flees from the experienced world because it appears as her tombstone, she unwittingly flees life itself.[15] William Blake has put a microscope on the conflict between innocence and experience and he has found that innocence must take on a more elevated meaning, one found through suffering, that Thel can never reach so long as she is gripped by her fear of opening herself up to risk.[16] The idea that Thel’s future life was one of despair and death can be read as another example of Thel’s skewed perspective. Thel is surprised by her brilliance and says that the world of experience looks like a “chamber of horrors.” It has also been suggested that the Worm has a part in the conflict between innocence and experience. The Worm is speaking as a messenger for the world of experience, and his words are inaudible to Thel because the Worm is not a part of her realm.[17] The Worm speaks of phallic sexuality and the guaranteed death of mortality. This creates a mediator when she gives the voice to the Clod of Clay. Now the Clod of Clay acts as an interface between innocence and experience.[17]
- "The Book of Thel is an allegory of the unborn spirit visiting the world of generation. Thel rejects the self-sacrificing aspects of experience and flies back to eternity. The symbols of Lily-of-the-Valley, the Cloud, the Worm and the Clod of Clay represent idealistic fancy, youth, adolescence and motherhood." —Geoffrey Keynes[citation needed]
- "The Book of Thel is best understood as a rewriting of Milton's Comus. ... Blake tells the same story, but in biological terms, not moral ones." —S. Foster Damon[18]