The real subject of ‘The Rehearsal’ is Nathan Fielder himself

Nathan Fielder, whose four-season series “Nathan for You” saw him “aiding” struggling small businesses with strange promotional ideas like poo-flavored frozen yogurt or rebranding a realtor as a “ghost realtor” whose properties are guaranteed to be spook-free, is back. “The Rehearsal,” premiering Friday on HBO, takes off from the idea that critical events can be prepared for, that “if you plan for every variable, a happy outcome doesn’t have to be left to chance.” Like the earlier show, and the myriad reality shows it half-mimics, it is presented as a sort of social experiment, and, in that it puts real people into artificial situations in order to elicit real reactions, even feelings, in some cracked way it is.

As in “Nathan for You,” part of the joke — perhaps the whole of the joke — is the length to which Fielder will go to achieve his ends, the elaborate, often expensive stratagems he employs, requiring the witting or unwitting participation of many hands. We are sometimes going to laugh at his subjects, at the amazing things people will agree to or the yards of wool that can be pulled over their eyes. But Fielder, who narrates and appears on camera and is personally, sometimes deeply involved in each project — never more so than in “The Rehearsal” — is the implicit subject of his work. And sometimes the explicit, as in the “Nathan for You” episode “The Anecdote” in which, fearful of being a dull guest on “Jimmy Kimmel,” he researches and invents the “perfect” story and then reverse engineers events to make it technically true.

“The Rehearsal” might have its roots in the final episode of “Nathan for You,” “Finding Frances,” an extended odyssey in which Fielder sets out to reconnect Bill Heath, a septuagenarian actor who imitated Bill Gates in that show’s second season, with a lost love. In one scene, he employs an actress to role-play with Heath to help predict what a reunion might look like; when that does not seem to go well, Fielder has Heath play the part of Frances. (He has a wig handy.) Role-play — and the surprising emotions it can call up — is the essence of “The Rehearsal,” which feels like an attempt to match the relative seriousness and ambition and artistry of “Finding Frances.” To be sure, any one of us, faced with a worrisome encounter, may obsessively imagine how it will go, think over what we’ll say. It’s that universality that gives “The Rehearsal” some relatable heft.

Though it will evolve into a serial, the six-episode series begins with a stand-alone episode in which Fielder helps a Brooklyn man named Core Skeet — who has responded to a Craigslist ad reading “TV Opportunity: Is there something you’re avoiding” — break the news to a friend that he has been lying about having an advanced degree. It’s a scheme that includes rehearsals in an exact replica of the bar where they participate in trivia nights, and not only hiring an actress to portray Skeet’s friend but arranging for them to meet, under false pretenses, so that the faux friend may more closely approximate the original. (Fielder has previously rehearsed his first meeting with Skeet, including the jokes he’ll make, in a replica of Skeet’s apartment; there will be other replicas to come.) Subsequently, the action moves to rural Oregon, where Angela (no last name given) is trying to decide about adopting a child; Fielder’s proposal is to employ an army of child actors in “a round-the-clock simulation of parenthood, to raise a child from 0 to 18 over the course of two months.”

This saga, which will involve Fielder intimately, continues through the rest of the series, along with one additional rehearsal and a detour to Los Angeles, where the creator has established a pop-up school teaching the “Fielder Method” to find and train up-and-coming actors in the specific techniques needed for this show. This digression, which plays with identity, is the show’s most radical conception, a sort of infinite regression, as Fielder, creating simulacrum upon simulacrum, becomes his own subject and takes over the role and briefly the life of one of his students.

Like more conventional reality TV, Fielder’s shows call up questions of truth and fiction, of whether, or to what degree, he’s committed to the experiment as opposed to being committed to the bit. Notwithstanding the new series’ premise, that everything can be accounted for, he is constantly called upon to adjust his plans to fit unforeseen circumstances and to ensure he’ll come out with some sort of story.

Even if he appears to be part of the experiment, as here, he’s in control of the experiment, participating in scenes he’s also directing. Situations are carefully engineered, sometimes transparently, but often without his subjects’ knowledge; that he lies, or encourages others to lie, is intrinsic to his method. He may finally tell the truth for supposedly moral reasons — because he feels bad about lying, he’ll say, though one would guess this is less to clear his conscience than to elicit a reaction. But it is also impossible to know. The premise and progress of “The Rehearsal” require him to be forthcoming to some degree — his subjects are also in a sense his collaborators — but we don’t know what we aren’t shown, after all, and no one can say how honest the seemingly heartfelt sentiments he expresses along the way are.

As “The Rehearsal” goes on, there is much occasion for self-reflection and Fielder’s almost trademark self-denigration. (He portrays himself as an awkward, lonely guy with cats; maybe he is.) “I often feel envious of others, the way they can immerse themselves in a world with so little effort, the way they can just believe.” Whether this adventure is a growth experience for him, or just a replica of a growth experience, is something you will have to decide for yourself.

“Maybe it’s easiest to choose a path when you can live the future first; to free yourself from doubt and regret; to always know the answers,” Fielder will say. Nothing in the series will prove this to be true — if anything, the point seems to be quite the opposite. (“That last step in understanding someone is always just a guess,” he will admit.) For all the questions it raises about itself, Fielder’s work is reliably fascinating, if not necessarily amusing; it is usually presented as comedy, but here it’s comedy of a particularly melancholic sort.

In the similarly downbeat “Finding Frances,” he’s asked whether “Nathan for You” is funny. “I don’t know,” he replies. “I hope. Sometimes.” In “The Rehearsal,” which sometimes feels like its own critique, he’s accused of turning people into jokes. “No one’s the joke,” he answers. “The situations are funny, but interesting too.” That seems a fair assessment of his aims, and often of his accomplishments.