The book uses a metaphor to describe the Abbess's efforts to reform her flawed and unjust society:
She resembled the swallow in the fable who once every thousand years transferred a grain of wheat, in the hope of rearing a mountain to reach the moon. Such persons are raised up in every age; they obstinately insist on transporting their grains of wheat and they derive a certain exhilaration from the sneers of the bystanders.
This metaphor in this passage compares the Abbess to a swallow who is determined to make a "mountain" of wheat but can only transport a grain "once every thousand years." The grains of wheat represent the many tasks she must complete and obstacles she must overcome in order to create the just society she envisions. Ultimately, this metaphor illustrates the doomed nature of the Abbess's quest: just as the swallow is unlikely to build a mountain, the Abbess can't accomplish everything she wants to, especially in one human lifetime.
At the same time, this comparison demonstrates the beauty and dignity of the Abbess's effort. A "mountain to reach the moon" is an amazing idea for a swallow to conceive. Likewise, even though the Abbess is mired in a backwards, often cruel society, she advocates social reforms that wouldn't even gain popularity as ideas for centuries. Depicting the swallow "obstinately" moving its grains of wheat, the book suggests that progress is achieved through the efforts of stubborn visionaries, even if it happens at an incredibly slow pace. The connection of the Abbess to likeminded people who are born "in every age" broadens the scope of her quest and emphasizes the timelessness of the novel's thematic concerns.
In The Bridge of San Luis Rey, twin brothers Manuel and Esteban have an unshakably close bond until Manuel falls in love with the Perichole. The novel uses a metaphor to describe the threat this new love poses to their relationship:
At last the first shadow fell across this unity and the shadow was cast by the love of women.
In this passage, the book compares "the love of women" to a shadow in order to convey the change that is occurring in the brothers' lives. This metaphor takes advantage of widespread associations between sunshine and goodness, and conversely between darkness and evil, to suggest that Manuel's new love will be detrimental to his relationship with Esteban. Although the narrator does not say explicitly that romantic attachments are bad for the brothers, they create an ominous atmosphere through this figurative language.
At the same time, this metaphor also suggests that "love of women" is a natural, even inevitable development in the brothers' relationship. Through shadows might be a less preferable alternative to sun, they're an inescapable part of the natural world. Just as it's impossible to live without shadows, it's impossible for Manuel and Esteban to avoid romantic feelings that challenge the primacy of their relationship as brothers. Through the comparison of the "love of women" to an essentially neutral natural phenomena rather than to something unequivocally bad, the book complicates the brothers' narrative arc. It suggests that the establishment of important emotional bonds outside their small family unit should not be a source of fear for the brothers.
Actress Camilla Perichole loses her young son Jaime in the bridge collapse. In the aftermath of the tragedy, Wilder uses simile and metaphor to express the Perichole's feelings about the funeral service held for victims, which she does not attend:
She thought of the vast ritual of the church, like a chasm into which the beloved falls, and of the storm of the dies irae where the individual is lost among the millions of the dead, features grow dim and traits fade.
Here, the Perichole uses a simile the elaborate rituals of the Catholic church to "a chasm" swallowing up her son. This sentence also uses metaphor to compare the Dies Irae (a Latin poem often included in Catholic funeral services) to a "storm" that will ultimately erase Jaime's memory.
The figurative language in this passage suggests that adherence to Catholic dogma can't provide consolation in the face of death. The "vast ritual of the church," which includes funeral masses that would have been familiar to everyone in this highly religious society, are meant to help people make sense of tragedies like the bridge collapse by slotting them within a theological framework. For the Perichole, however, these impersonal rituals compound her loss by erasing her son's memory. Imagining him disappearing into a "chasm" and disappearing among "the millions of the dead," she's envisioning a future in which even the people who loved Jaime most won't be able to remember him.
Ultimely, the Perichole visits the Abbess for spiritual guidance and learns that love, not dogma, is the best salve for grief. By the end of the novel, the Perichole has devoted her life to assisting the Abbess, finding tranquility through altruism. In her final speech, the Abbess notes that while only the Perichole preserves the memory of her son, the love she holds for them will survive both their deaths and become a "bridge" between the living and the dead. Arguing that the collapse victims and their loved ones are connected forever by love, the Abbess articulates a philosophy of grief predicated on care and sympathy for one's fellow people rather than rote obedience to institutions like the Catholic Church.
