One of literature’s most striking descriptions of the creative process can be found in Vladimir Nabokov’s novel “Pale Fire.” An academic, Professor Kinbote, recalls standing on a terrace with the poet John Shade. Shade, he says, is soaking in the view: “perceiving and transforming the world, taking it in and taking it apart, re-combining its elements in the very process of storing them up so as to produce at some unspecified date an organic miracle, a fusion of image and music, a line of verse.” The moment reminds Kinbote of one from his childhood, when he watched “a conjurer . . . quietly consuming a vanilla ice.”

Nabokov disliked the idea that others would search his writing for glimpses of his personal life. In a 1944 biography of Nikolai Gogol, he stated his disdain for “the morbid inclination we have to derive satisfaction from the fact (generally false and always irrelevant) that a work of art is traceable to a ‘true story.’ ” Novels, Nabokov felt, were best regarded as the ex-nihilo dreams of their creators.

The passage from “Pale Fire,” though, complicates that picture. Here, art does not arise ex nihilo; rather, it is reconstituted from the view from the balcony. Reality and fantasy seem to commingle in Shade, who melts together, in Kinbote’s mind, with the conjurer, appearing hazily out of the past. The poet ingests life and produces a poem, a “sudden flourish of magic.”

What sticks with me about this description is not Shade’s—or Nabokov’s—impressive artistry but all of the slippage and combination, which provokes, in my head, a vague uneasiness. Shade is a writer, a surrogate for Nabokov, and he is also a ghost, a memory dining on shadows—the glitter and impermanence of ice. The reader cannot trust this man.

I started writing this essay in order to understand what fiction is made out of. The question is sort of like the one that always gets asked at the end of an author event, perhaps by a cute old lady whose sweater has a schnauzer on it: Where do your ideas come from? I was accustomed to thinking of most novels the way Nabokov wanted me to, or as Flaubert did—he once wrote that the most beautiful books depend “on nothing external . . . just as the earth, suspended in the void, depends on nothing external for its support.”

Then something happened to change my thinking. I realized that the real world is full of people who, presumably, have feelings about being appropriated for someone else’s run at the Times best-seller list. In drafts five through seventeen of this essay, I was mostly concerned with them: with the experience of opening a book and finding yourself in its pages, and with comprehending the precise nature of that violation. In drafts eighteen through eighty-four, I realized that the stakes of this piece are less aesthetic or ethical than metaphysical. When an author plants a made-up character in a novel, that character gains breath, agency, life. But when an author plants a real person in a novel, she metes out a kind of death. Reading lightly autobiographical fiction—which is to say, most début fiction—or its cousin, autofiction, or really any and all fiction, becomes a matter of parsing degrees of realness. It’s sticking your hands through ghosts. I suppose one could reintroduce both ethics and aesthetics here. Is moving someone down the existence scale from “human person” to “character” anything like murder? Is moving someone up the scale anything like art?

Susan Choi has a thrillingly interesting new novel out, “Trust Exercise,” which toys with themes of appropriation, and with the reader. (From here on out, spoilers abound.) The first part is a straightforward tale of two teen-agers, David and Sarah, whose time at a performing-arts high school in what seems to be Houston in the nineteen-eighties, is shadowed by the attentions of a magnetic teacher, Mr. Kingsley. Because Choi herself attended a performing-arts high school in Houston in the early nineteen-eighties, the reader may assume that she is recombining personal experience as fiction. (There’s where your ideas come from!)

It is not until the second part of the book that we learn that the first part is an excerpt from a novel written by the adult Sarah, who has blurred and revised elements of her past. Choi gives the narration of the second section to “Karen” (we never learn her real name), a high-school friend of Sarah’s. Karen has an excellent memory and a chip on her shoulder. She is well versed in therapy jargon and beguiled by etymology—a study of particular relevance to anyone set down in an alien narrative and rummaging for her meaning within it.

“Trust Exercise” circles varieties of trust like a thief casing a jewelry store: the trust between teacher and student, performers and audience, a writer and her subject, a writer and her reader. At times, Karen “can see through” Sarah’s book as though it were a phantom: “as easily as drawing a line from a column of things on the left to a column of things on the right.” But Sarah does not always work so neatly. As Karen reflects:

Pammie, unlike Mr. Kingsley, is not a historical person but the way in which Karen’s Christianity was found laughable. Julietta is the way in which Karen’s Christianity was admired. Joelle is the intimacy between Karen and Sarah, disavowed and relocated onto a historical person very much like Joelle with whom Sarah did not have an actual friendship. Why give the pain of broken friendship to Joelle, why take it away from Karen? The reasons might be psychological. Why make Karen non-Christian, while making her laughable Christianity Pammie, and her admirable Christianity Julietta? The reasons might be artistic.

Even as she intellectually understands that Sarah writes fiction, Karen approaches the novel uncomprehendingly, with a kind of mental stutter-step. She can’t help but read the book as history. She finds herself adjudicating conversations that never occurred, lies that no one told. It’s as if, when invented details are juxtaposed with real details, something about the creative mind-set or process refuses to compute: Why take some but not all? Karen inspects the Sarah character’s made-up actions for evidence that Sarah is a good or bad person. She proceeds, dizzily, as though Sarah were a more reliable narrator than she herself is. “Sarah’s reconstruction in her book of the lighting and set and backdrop were so true to my memories,” Karen recounts. “I kept blaming myself that the action seemed unfamiliar.”