In Part 2, Chapter 14, the narrator compares the Marabar caves to gods with a metaphor that evokes not only their grand stature, but also their impenetrable mystery:
Astonishing even from the rise of the civil station, here the Marabar were gods to whom earth is a ghost. Kawa Dol was nearest. It shot up in a single slab, on whose summit one rock was poised—if a mass so great can be called one rock. Behind it, recumbent, were the hills that contained the other caves, isolated each from his neighbour by broad channels of the plain.
The primary metaphor in this passage—"the Marabar were gods"—speaks to the beauty and grandeur of this natural feature. A second metaphor—"to whom earth is a ghost"—makes the earth seem utterly insignificant. The juxtaposition of the grand, looming Marabar and the unremarkable surrounding land make the caves seem all the more humongous. The narrator continually emphasizes the vastness and beauty of the caves, but sharp readers might wonder: what are caves but emptiness? What do caves produce but echoes? The caves, much like human ideas about love and relationships, seem very grand. But if readers look a bit closer, they might find more questions than answers.
The narrative metaphorically presents the connection between Aziz and Mrs. Moore as a flame. In Part 1, Chapter 2, Mrs. Callendar and Mrs. Lesley steal Aziz's tonga (carriage). He later complains to Mrs. Moore, another Englishwoman, that he is "just a subordinate" to the English and that his "time is of no value" to them. She listens to his complaints with sympathy, and he is excited by the unlikely prospect of friendship with an old Englishwoman:
He was excited partly by his wrongs, but much more by the knowledge that someone sympathized with them. It was this that led him to repeat, exaggerate, contradict. She had proved her sympathy by criticizing her fellow-countrywoman to him, but even earlier he had known. The flame that not even beauty can nourish was springing up, and though his words were querulous his heart began to glow secretly. Presently it burst into speech.
The "flame that not even beauty can nourish" metaphorically refers to a feeling of kinship or even love. It makes Aziz's heart "glow secretly"—perhaps it must remain a secret because the friendship between an old Englishwoman and a young Indian man seems nearly impossible in the context of this story.
In A Passage to India, this moment is all the more special for how unlikely it seems. Usually, Forster uses the word "flame" to refer to negative emotions like suspicion or loneliness. A good example of this arises in the description of a visitor striking a match in the darkness of the Marabar Caves: "Immediately another flame rises in the depths of the rock and moves towards the surface like an imprisoned spirit." However, the flames will never meet, "because one of them breathes air, the other stone." The flame and its reflection symbolize the difficulty of human connection in contrast to the secret joyful warmth that Aziz feels upon talking with Mrs. Moore in the mosque. The metaphor of the flame finds resonance throughout the story, but it burns most brightly in Part 1 as an unlikely pair discovers a strange sort of kinship.
The concept of "traveling light" becomes a metaphor for personal freedom. In Part 1, Chapter 11, Fielding uses it to make a case against marriage and religion:
“I travel light.”
“Travel light! You are a most extraordinary race,” said Aziz, turning away as if he were going to sleep, and immediately turning back again. “Is it your climate, or what?”
“Plenty of Indians travel light too—saddhus and such. It’s one of the things I admire about your country. Any man can travel light until he has a wife or children. That’s part of my case against marriage. I’m a holy man minus the holiness. Hand that on to your three spies, and tell them to put it in their pipes.”
Here, Fielding and Aziz discuss the relative abilities of English and Indian men to "travel light." Aziz believes that all Englishmen have the ability to do so. But according to Fielding, any man can do it, provided they do not have a wife or children. Refusing to marry and becoming a "holy man minus the holiness" permits Fielding to travel light. He has a lot of freedom to make decisions about his work and personal relationships. This gives him a sense of power over his own life.
The narrator spends a bit of time throughout the novel describing the benefits and drawbacks of "traveling light." After chatting with Fielding, Aziz thinks, "So this was why Mr. Fielding and a few others were so fearless! They had nothing to lose. But he himself was rooted in society and Islam. He belonged to a tradition which bound him, and he had brought children into the world, the society of the future." Aziz becomes jealous of Fielding, and he tells him that his "boastfulness about traveling light will be [his] ruin."
Throughout A Passage to India, the metaphor of traveling light serves as a euphemism for remaining unattached, unaffectionate, and uncaring on a deeper level in order to maintain a safe sort of independence. Maintaining one's own freedom at first seems like a romantic idea, but it has consequences including loneliness and uneasiness. Of course, the question of personal freedom begs the larger question of political freedom—that of India from the British Empire. This novel tends to juxtapose interpersonal relations with the looming issue of colonialism, and Fielding's concept shows how differently the English and Indians approach relationships—the former with linear, rational detachment, and the latter with a sense of overarching unity.