The character Fielding calls Adela Quested "one of the more pathetic products of Western education" (1.11.42).
But you can kind of see where Fielding's coming from. All fresh-faced earnestness when she arrives in India, Adela is perhaps the last person you'd want to take along on a trip to the mall, let alone an exciting tour of India. For Adela seems to be a character who takes the cliché that your "life is an open book" quite literally. She studies everything as if she were prepping for the SATs, as if there were vocabulary lists and formulas that could explain life, love, and human nature.
So when Adela keeps talking about seeing the "real India" in the beginning of the novel, it's hard not to read that phrase as a desperate plea for help. A plea not just to see past the official, sanitized version of British India, but also to escape her overly cerebral way of looking at the world. A plea to feel, to feel passionately, to really experience the world. Adela may know a lot of facts and figures, well-educated, progressive young woman that she is. But she doesn't know how to handle the mess and muddle of personal drama and interpersonal relationships.
You could say that her traumatic experience in the caves might represent the culmination of a series of minor crises Adela undergoes in the novel as her cerebral self keeps getting gob smacked by her unpredictable emotional life. Particularly in her relationship with Ronny, Adela is constantly puzzled over the fact that their interactions are so...ordinary. There are no dramatic speeches, declarations of love, romantic letters, tears, embraces, and more tears. There's just the touch of a hand in a car, and poof, they're engaged.
Which brings us to the caves. What actually happens to Adela continues to be the subject of debate. Forster intentionally left that crucial narrative morsel out of the novel. And in Adela's explanation of what happened after the cave incident, she stresses that "[h]e never actually touched me once" (2.22.2). So what does this cave episode tell us about Adela?
Well, given the clueless way she goes about thinking about love and marriage, one way to look at the scene is to side with Fielding. Adele's situation is pathetic. Her whole charge against Aziz is just the hysterical fantasy of a silly, self-absorbed girl. She may have been "attacked," but the attack was a hallucination driven by her need for drama, by her disappointment with how bored she is with travel and with her love life. You could be even more cynical, as some critics are, and suggest that the fact that she's thinking about India and love right before she enters the cave indicates that her attack is an erotic fantasy, driven by a sexual attraction to Aziz that would have been unthinkable to act on in that time.
Perhaps. Or you could follow Fielding one step further. Even Fielding realizes that he was a little hard on Adela, and he's struck by her sincerity in their conversations after the trial. While the rest of the Anglo-Indians went nuts with racial hysteria, Adela was, in a way, saved by her own dispassionate way of looking at things, the very quality that made her such a "pathetic product of Western education" in the first place.
We will never know what actually happened in the cave, but it's useful to keep in mind Fielding's thought that after the trial, Adela "was no longer examining life, but being examined by it; she had become a real person" (2.26.68). As her name implies, Adela is no longer on a quest, but being "quested." The stress is no longer on the "real India," but on Adela as a "real person." Does the novel really give Adela a chance to become a real person? Your answer to that question depends on how you fill in the gap in the cave.