"Tintin, quel âge as-tu ?"
Today marks 96 years of The Adventures of Tintin, and readers have spent at least the last 78 of those years asking the same question: "How old is Tintin?"
The series is infamously coy about giving a definite answer, as was its creator, but I argue in the first part of this post that 1) there was indeed a specific intended age range for Tintin and 2) it is very much possible, using evidence from many different sources including the albums themselves, Tintin magazine, other BDs of the time, and interviews with Hergé, to say exactly what that age range was. Let me be very clear: I'm specifically making an argument about how old Hergé saw him as and how old Hergé wanted him to be seen as.
The second part is less concrete; it presents how a few scholars have interpreted the ambiguity of Tintin's age, plus some of my own thoughts about it that build on their claims. That part is less trying to find an answer to the age question and more trying to explain why his age is so much in question.
When asked about Tintin's age in a 1960 interview for Cinq colonnes à la une, Hergé judged that "il doit rester aux environs de quinze ans" ("he must still be around 15 years old," 0:33-0:44).
In 1962, he gave a very similar response on the Canadian program Premier Plan: "Une quinzaine d'années ? Quinze ans, seize ans, je ne sais pas, moi" ("About 15? 15, 16, I don't know"). "Donc c'est l'adolescent" ("So he's a teenager"), pursues the interviewer, and Hergé answers with a firm yes.
Nearly ten years later, in 1970, he added some nuance: "What age do I give him? I don't know... 17? In my mind, he was about 14 or 15 when I created him, a Boy Scout, and he practically hasn't budged. Let's say that he's picked up three or four years in forty years... All right, let's take the average: 15 plus 4, 19." (translation mine)
In 1979, his interviewer on Apostrophes preempted him on the age question, saying that "c'est un reporter de quinze ans" ("he's a 15-year-old reporter"). Hergé agreed: "C'est ça, à peu près" ("That's right, more or less").
Today, the official Tintin website run by Moulinsart declares him to be "Seize, dix-sept ans (dix-huit tout au plus !)," that is, "16, 17 years old (18 at most!)."
Responses to reader questions in the Journal Tintin
Early in the Journal Tintin's run, between 1946 and 1954, readers who wrote in with questions had a chance to see the responses to their letters published in the magazine each week. Supposedly it would be Tintin himself who was answering - questions addressed to him would be answered in first person, which probably only increased the urge to ask about personal details. So there were naturally many questions about his age, which provoked a range of responses.
Who was actually answering the letters? It's hard to say. But seeing as the responses were being published in the official Tintin Magazine as the voice of Tintin himself, Hergé would surely have been at least consulted on questions concerning his character, especially as the team running the magazine was still very small when it was regularly publishing responses.
The most common response was to dodge the question entirely. The stock phrases were "Qu'importe mon âge ?" and "Tintin n'a pas d'âge !" ("What does my age matter?" "Tintin has no age!").
In a small number of cases they related Tintin's age to that of his readers; an 11 1/2 year old was told that Tintin can be "l'âge que tu souhaites : entre dix et vingt ans !" ("whatever age you want: between 10 and 20!", 1953), and for a couple others, where the age of the writer wasn't listed, Tintin's age is "un peu plus que le tien" ("a little older than you," 1951) or "un peu moins que le double du tien" ("a little less than twice your age," 1950). The target audience of the Journal Tintin - as it was for the Petit Vingtième, and for comics magazines of the time generally - was 8-15 year olds.
The only definite answer that appeared with regularity put Tintin's age between 15 and 20:
(TIntin nos. 19, May 8, 1947; 26, June 26, 1947; 6, February 5, 1948; 2, January 12, 1950; 9, February 27, 1947. The second and third examples also have Tintin declare that "I've travelled so much that I no longer remember where I was born," a fine example of the de-Belgicanization he underwent after the early years.)
("As I've already told several of my friends, I'm older than 15 but younger than 20." (1947)
"My age? Let's say 15… or a little older." (1947)
"My age? Between 15 and 20 years old." (1948)
"Tintin? He has no age! Seeing him move about, he seems to be about 15." (1950)
"I'm not yet 20 but I'm older than 15." (1947))
Real-life incarnations of Tintin
When the end of Soviets was celebrated with "Tintin" arriving at the Gare du Nord in Brussels, the role was played by 15-year-old Lucien Pepermans. When the event was repeated for the end of Congo, two years later, Pepermans was replaced by Henri Dendoncker, age 14. About thirty years after that, Jean-Pierre Talbot was declared Tintin's spitting image at 16 ("Same age, same silhouette, same face, same hair," reads the announcement of his casting in the Journal Tintin). He was 20 at most when Blue Oranges (released 1964) was filmed. Hergé told Numa Sadoul that he unconsciously based Tintin in Soviets on his younger brother Paul, who was 16 when it started. Additionally, Palle Huld, often cited as an inspiration for Tintin, completed a tour of the world in 44 days in 1928 at age 15 (and in plus-fours).
(Lucien Pepermans, Henri Dendoncker, Jean-Pierre Talbot, Palle Huld)
In the play Tintin et le mystère du diamant bleu (1941), which Hergé was very involved in the writing and production of, the role of Tintin was played by Mlle. Jeanne Rubens, a woman - a common theater trick for portraying young boys. He was played by a woman again in Radio Luxembourg's 1950s audio adaptations: Claude Vincent, "qui interprétait à merveille les rôles d’enfants et d’adolescents" ("who played children's and adolescents' roles wonderfully"), was the voice of Tintin. Sadly those broadcasts appear to be lost, but she can still be heard in the likely similar role of Alix.
(Shared on forum-tintinophile.com, "Tintin aux Indes, ou le mystère du diamant bleu." Certainly the only adaptation that got his height difference with the Thompsons right.)
In 1959, the Journal Tintin invited readers who thought they looked like Tintin to send in their pictures; five candidates for "Tintin's lookalike" were chosen by the magazine and presented to the readers for them to vote on. The winner was a 15-year-old, and while the ages of the other contestants aren't listed, they appear to be the same age or younger.
(Tintin nos. 25, June 24, 1959 & 31, August 5, 1959)
Comparisons with contemporary characters
Mainstream BD in the first half of the 20th century was not particularly inventive, especially as it was contending with its relative youth as a medium, a focus on the children's market, and, especially after WWII, heavy scrutiny from both religious and secular moral watchdogs. In the specific case of the Journal Tintin, Hergé's iron-fisted artistic direction in the early years led to a high level of artistic homogeneity across the magazine, while restrictions on the types of stories that could be told (from both the threat of censors and expectations about reader interests) limited variety in plots, characters, and settings.
All that is to say that a lot of what was being published alongside Tintin in the 40s and 50s looked more or less like Tintin, and even was likely directly modeled on it, which makes it useful for comparison. The protagonists of the time can be generally divided by age into children, the "15-20" range, young men, and middle-aged men. Each category is visually distinct (comics are a visual medium!) and each results in a slightly different kind of story with different character dynamics.
Here's Tintin with a couple of the teenage protagonists that appeared alongside him in his magazine:
(L'Affaire Tournesol (1956), p. 51; La Griffe Noire, Tintin no. 6, February 5, 1958; Les Deux Visages de Kid Ordinn, Tintin no. 1, January 2, 1957)
Hergé's no. 2 collaborator Jacques Martin created Alix (center, 1948), a Roman Gaul confirmed to be 16 in the original albums. Chick Bill (right, 1955), who in looks and narrative role is effectively just Tintin as a cowboy, is identified (by none other than Franquin) with the 15-20 age range. Some shared visual markers of their youth are a short and slight build, rounded shoulders, a round head, and a soft jawline. While all very independent, they are all three semi-accompanied by a much older man and a child sidekick.
Now, here are some examples of characters from the next age range up:
(L'énigmatique Monsieur Barelli, Tintin no. 44, November 2, 1950; L'ouragan de feu, Tintin (Kuifje) no. 37, September 15, 1960; Défi à Ric Hochet, Tintin (Kuifje) no. 8, February 25, 1964)
Hergé's no. 1 collaborator Bob de Moor had a humor-adventure series using the same style as Hergé, but his character, stage actor Georges Barelli (left, 1950), is a grown man. Martin's second series was required by publishers to somehow be a modern AU of Alix, but Alix's counterpart, reporter in the same way that Tintin is a reporter Guy Lefranc (center, 1952), is clearly older than him. So-called reporter, really amateur detective Ric Hochet (yes, that's his name, right, 1955) is kind of an odd case; he started out a child, then looked basically exactly like Chick Bill (they were both drawn by the same artist, Tibet), then finally settled into his final form as a young man in his mid-twenties - a 1969 album places him at age 26. All three own their own cars (admittedly a moot point for Alix and Chick), and, compared to their teenage counterparts, they're much more likely to have friends and colleagues their own age instead of being supervised by someone older.
It should be clear from these six pictures that Tintin was not drawn in a way meant to make readers think he was an adult. And besides, there's really no reason to believe that Hergé, who once declared that "my primary objective is to be legible. The rest follows," would have chosen to give his main and titular character an appearance that was somehow deceptive. I'm prepared to say with confidence that Tintin looks young because he's supposed to be seen as young.
For this section, I first look at a few ways that the albums actively present Tintin as a non-adult character. However, most of what follows is about showing that what happens in the albums does not contradict the argument that Tintin is intended to be a teenager. The Adventures of Tintin may be deceptively timeless, but not only is the series nearly a century old, it also was written during a time of extremely rapid and intense social, cultural, and technological change. Consequently, I want to make sure that I'm not judging the past with the attitudes of the present; in order to put the series in its proper context, I try to identify viewpoints and conventions expressed in texts created at the same time (and, when possible, by the same author) to see if a teenaged Tintin fits in with them.
In looking over how other characters refer to him across the albums, one sees that Tintin's most distinctive feature to those around him is his youth. This is, I think, more visible in the original French, where other characters address or describe him with a whole array of words commonly used for children: jeune homme, (jeune) garçon, gamin, galopin, blanc-bec, enfant de choeur, fiston, freluquet, moussaillon, (mon) petit (used as a noun), and morveux, not to mention many, many instances of characters appending "jeune" or "petit" to another word ("reporter," for instance). In English, he's variously (a) young man, (young) boy, kid, boyo, whippersnapper, wonderboy, lad, brat, puppy, young fellow-me-lad, and cabin-boy, along with liberal use of the corresponding adjectives "young" and "little." (I've collected specific panel examples for reference in another post.)
As @professorcalculusstanaccount has pointed out, there's no question of Tintin being called up for the draft as Haddock is in Black Gold; that album also contains the only example of Tintin's competency being questioned because of his age, on page 7: "So you're the new radio officer... You look a bit young to me..." (There's one similar remark, in America, after Tintin is injured in a car accident on page 6: "The poor kid..." "He looks so young...") Him not being called to war is particularly striking because Belgium historically required young men to do compulsory military service at age 18 or 19, after which they would be enrolled in the reserve army (p. 274). Thanks to a hard-to-translate joke in the original French for Emerald (below), we know that military service exists in Tintin's world and that the Thompsons have done theirs; Hergé did his at age 19, and then was called up from the reserves in 1939, interrupting the magazine publication of, precisely, Black Gold. Given his longtime anti-war stance and the peace sign sticker he wears in Picaros, though, one can easily imagine Tintin becoming a conscientious objector after it was legalized in 1964 - but by 1964, most of the series was already over.
(Les Bijoux de la Castafiore, p. 37)
He also doesn't dress like an adult: the plus-fours look very childish after the 1930s, as @illegally-blind-and-deaf pointed out. He also never wears a proper hat, only a flat cap in a few early adventures, and from Temple on (that is, after 1948) he runs around in his shirt and sweater with no tie or jacket. Some of that can be put down to the importance Hergé placed on his characters being maximally recognizable, but it certainly doesn't make Tintin look any older - look at a few of Hergé's crowd scenes and compare how the background characters are dressed.
Next, he doesn't seem to ever need to shave. In fact, in the original French for Black Island, Tintin remarks that the bad guys have gotten away "à mon nez et à ma barbe," an expression equivalent in English to "right under my nose" but literally "at my nose and at my beard," to which Snowy incredulously responds "Your beard? What beard?"
It's true that nearly everyone who meets Tintin, including his adult friends, addresses him respectfully with the formal pronoun "vous" instead of with the informal "tu," as you typically would for someone much younger than you. However, Pierre Assouline attributes this to a dislike of over-familiarity on Hergé's part, citing him as saying that "Le tutoiement est la fausse monnaie de l'amitié" ("Using 'tu' is the counterfeit money of friendship").
(There are a few moments where Haddock slips and uses tu with Tintin, but I won't go into them here. Suffice to say that the majority of them are indeed moments where he's treating Tintin more as a child.)
Much has been made of Tintin's nonchalance about drinking alcohol as proof of adulthood, but evidence from other BDs indicates that this perception is a result of a shift away from historically looser attitudes towards drinking. Early comics for children frequently carried moralizing messages, but there's no marked moralizing present around youths drinking like there is around them smoking.
Compare, for example, the difference in tone between these two Quick & Flupke pages, where the kids are sternly warned off from tobacco...
(Originally published in Le Petit Vingtième nos. 4, January 28, 1932 & 43, October 24, 1935)
...Versus this gag, where Flupke's own relatives getting him drunk on New Year's over his protests is played entirely for humor.
(Le Petit Vingtième no. 1, January 3, 1935. "Tu es un homme et tu dois boire!")
There was even a follow-up comic at the same time the year after, in which Flupke imagines the alcohol he'll be plied with on January 1st and attempts to move to the North Pole to avoid it.
If a kid as young as Flupke is being given alcohol, then Tintin really doesn't have to be much older to be drinking as well. In fact, one might even note an echo between Flupke's reluctance to drink here and Tintin's in Picaros, when he's pressured to take a swig of whisky by Arumbaya custom (p. 34). On the other hand, since Quick and Flupke are so young, the ban on smoking is stronger for them. Tintin is old enough to occasionally be offered a cigarette, but still young enough that he always must refuse: Hergé was adamant that Tintin remain a good model because of the children who identified with him, while Haddock smoking his pipe, for example, never raised the same issue.
Beyond that, for a non-Hergé example and a later one (from 1960), here's child tennis prodigy Jari, hero of an eponymous strip in the Journal Tintin. He's just bicycled from Belgium to the Netherlands and wants a refreshment, so he goes to a drink stand and orders a beer - and no one bats an eye. Similarly, the only alcohol that Tintin orders casually, in a cafe or pub, is beer (Golden Claws p. 2, Black Island p. 41).
(Jari et le Plan Z, Tintin (Kuifje) no. 40, October 6, 1960)
At the same time, this relaxed attitude has limits. Tintin won't share a friendly drink with Haddock, for example when returning to Marlinspike after an excursion (though Haddock pours two glasses anyway in Affair (p. 3)). Calculus scolds Haddock severely when he thinks that Haddock has given Tintin champagne at breakfast in Tibet (p. 4: "Vous avez bien tort de lui faire boire du champagne de grand matin, à ce garçon !…"). Later in that same album, Haddock drunkenly warns Tintin against alcohol, telling him it's "very bad for young people like you!" (p. 38).
Next, while Tintin is undeniably capable of driving a car, there's actually no indication outside of the earliest stories that he can legally drive. (A quick Google search also tells me that Belgium has historically been notoriously lax on road safety.) At no point after the first four albums - that is, after Hergé became interested in telling a story that makes logical sense, a development typically placed at Blue Lotus - does Tintin drive a car that was acquired legally, not commandeered or outright stolen. (In Soviets and Congo he buys a car; in Cigars he drives the two Rajaijah victims to the asylum, though I doubt anyone was worried about him getting pulled over in the jungle.) On the few occasions where there isn't an emergency, it's always Haddock who drives; see for example Crystal Balls or the few pages of Thérmozéro. When Tintin finally gets a vehicle of his own, in Picaros, it's... a motorbike, which one can get a license for at a younger age than for a car. And in Alph-Art, where the motorbike plays a much larger role, Haddock still drives Tintin into town (p. 25) - and then gets left in the car while Tintin investigates!
Hergé also apparently didn't think flying a plane was particularly difficult. In Jo et Zette, one of his other series, Hergé has little Jo be able to fly his father's "Stratonef" and even land it from a glide, despite only ever hearing his father talk about how to fly it. Over the course of the two-part story (Le Testament de M. Pump and Destination New-York), Jo manages multiple successful flights - more than Tintin ever does! - despite unambiguously being a child.
(Destination New-York, p. 41)
And as with the cars, every plane Tintin ever flies is stolen, so whether he has a legal license or not really doesn't matter.
The same goes for his guns. In all but the first albums and Ear where, surprised in his flat, he really does pull a revolver out of nowhere, Tintin's guns are explicitly either given to him or taken from a disarmed enemy. The series doesn't make a point of him owning and carrying his own gun - just the opposite. And while it seems to us now that Tintin has a lot of firearm use for a children's comic, proficiency with guns was honestly a genre expectation for all adventure heroes of the time (just don't put a gun on your cover). For example, Chang, who from his introduction on acts like a second Tintin, wields a pistol at the end of Lotus and is even implied to be the one who makes the shot that breaks Didi's sword despite appearing even younger than Tintin. (See also the previous section of this post; Chick Bill is carrying a gun in the picture I included.) What's more, the gunplay in Tintin is actually a step down from its predecessor Totor, where Hergé's titular Boy Scout kills a man with a rifle shot to the face.
In short, Tintin is able to do a lot of things he shouldn't legally be able to do by simply not doing them legally.
The fact that Tintin lives alone isn't necessarily a mark of maturity either. It's hardly uncommon for a young adventure protagonist to be unusually unsupervised; it's effectively a demand of the genre. Hergé learned why that is from experience when he created Jo et Zette for the editor of the French, ultra-Catholic children's magazine Coeurs Vaillants, who had raised concerns about how unrealistic Tintin was. In Hergé's own (translated) words:
(From Entretiens avec Hergé, reproduced & translated in The Comics Journal no. 250, p. 191)
Parents are a nuisance, one that Hergé was only too happy to dispense with in Tintin's case. And besides, Tintin isn't completely alone forever; with the introduction of the Marlinspike "family," not to mention Marlinspike Hall itself, during the war, he at least ends up with a home and some adult supervision, however dubious it may be at times.
As for his schooling, according to a report on the Belgian education system from 1932, education was only compulsory there (not to mention free) from ages 6 to 14. That same report records that in 1928, the number of students in the higher level of secondary education - corresponding to high school in American terms - was only 1% of the number of students enrolled in compulsory primary school. Even adjusting for the fact that primary education enrolls children for twice as long, the percentage is still a paltry 2.6%. And then the number of students in university that same year was only about three-quarters of the number of students in secondary education.
What that means is that at the time when Tintin was getting started, only very, very few people stayed in school beyond age 14. Hergé himself was one of those few, but to many of his readers in the early years, the idea that Tintin was already working at age 14 or 15 would have been not just reasonable but recognizable - especially as he has no apparent family to support him. (Not that Tintin isn't knowledgeable: judging from the number of books in his apartment, we can presume that he's quite the autodidact.) Of course public education was broadened after WWII, but by then the character was already firmly established.
As for how Tintin is already a reporter, well, Hergé freely admitted that he gave him the job just because that's what he thought was cool at the time. "Of course it was a pretext," he said on British radio in 1977. (The announcer for that interview describes Tintin as "a 16-year-old Belgian boy with a strange lick of hair, a pair of plus-fours, and a terrier." In it Hergé, questioned about the outsize success of his series, responds that for him "he [Tintin] keeps to be a little boy. Only that.") The tone of the series would be very different if Tintin were just an office clerk or a paperboy, after all - and besides, all but the youngest readers of Le Petit Vingtième would have understood that it's not a real newspaper, just a little children's magazine, so the idea of it having its own official reporter was not to be taken fully seriously.
It's important to remember that our current cultural idea of the teenager as a separate, unique stage between childhood and adulthood was largely a post-WWII American innovation - in fact, the word "teenager" only entered popular use in the 1940s. By contrast, fully half of the Adventures of Tintin (up to the first 2/3 of Crystal Balls) were written either before or during WWII. Hergé himself, born in 1907, began submitting illustrations to a magazine (Le Boy-Scout) at 14, was hired at the Vingtième Siècle at 18, created Totor and did his military service, reaching the rank of sergeant, at 19, and before turning 22 had been given full responsibility for creating and running the Petit Vingtième, gotten engaged to his first wife, Germaine Kieckens, and created Tintin. Being young looked different then.
To close this section I'll also note that, as far as I can tell, positioning Tintin as a teenager never seemed to pose much of a problem to anyone reading the series while it was actively running. Anecdotally, nearly every published source I've read takes for granted that he's an adolescent, and an exception like writer of multiple books on Tintin Renaud Nattiez saying on the air in 2016 that he thinks Tintin is at least 22 (~03:30-03:50) seems to be a uniquely 21st-century development.
TL;DR: Everything I can find indicates that Tintin was always intended to be around 15, and never older than 20, years old.
Finally, it's important to not overstate Hergé's commitment to realism. At the end of the day, Tintin can do whatever the story needs him to be able to do, because he's the protagonist of a very straightforward adventure serial. He's always been aspirational, even for Hergé himself: "Tintin is me the way I'd like to be: heroic, flawless." And yet Tintin, victim of its own success, has always been held to a higher standard of realism than its fellow comics, not to mention a higher level of scrutiny in general. Even if, as I've tried to demonstrate, Tintin's feats aren't entirely out of the range of possibility (or at least the norm for comics characters) for his time period, I'm not arguing that he's supposed to be a perfectly accurate representation of the average boy of any point in the mid-20th century. I also don't deny that he typically does act like an adult. So the guiding question here is: How can this dual nature of Tintin's - his adolescent status and adult aspects - be interpreted?
Jean-Marie Apostolidès writes that as "il unifie dans sa personne deux aspects opposés de l’existence, l’enfance et l’âge adulte" ("he brings together in his person two opposing aspects of existence, childhood and adulthood"), Tintin represents "un mythe réconciliatoire" ("a reconciliatory myth") of which the "fonction implicite est de ressouder entre deux générations une confiance brisée" ("implicit function is to mend a broken trust between two generations"). He names this type of child-adult character the "surenfant" ("superchild"), and argues that it is specific to the 20th century and the cultural shock of WWI.
For Pol Vandromme, who wrote the first book of analysis on Tintin (or on any BD), Tintin is simply a perfected version of the teenage boy, one that other teenage boys can aspire to. First, he cites as conventional wisdom that Tintin is around 15, and concludes that "c'est dans tous les cas un adolescent" ("in any case he's a teenager"). While Vandromme accepts that Tintin is presented as a teenager, he also points out that Tintin doesn't represent the experience of being a teenager; Tintin "ne présente [...] que les apparences de l'adolescence" ("only displays the appearance of adolescence") because he's so self-assured and stable, traits antithetical to "l'époque de la métamorphose" ("the time of metamorphosis") that is adolescence.
And yet "il [Tintin] demure malgré tout suffisamment proche pour que les garçons se disent qu'ils auront un jour la chance de lui ressembler, d'imiter son style de vie. [...] Ce que Tintin propose à ces garçons de quinze ans, c'est la figure achevée de leur âge. Il les venge de leurs insuffisances" ("he [Tintin] remains all the same close [i.e. similar] enough that these boys tell themselves that one day they'll have the chance to be like him, to imitate his way of life. [...] What Tintin offers to these 15-year-old boys is the perfected version of their age [group]. He makes up for their shortcomings"). Consequently, having put themselves in Tintin's place, these boys "ont l'illusion d'être déjà de la tribu des jeunes gens qui ont découvert dans leur sac de voyage les clefs qui ouvrent les portes de la fable du monde" ("have the illusion of already being part of the clan of young people who have discovered in their travel bag the keys that open the doors of the world's fable"). In plainer language, being able to identify with Tintin as an apparent peer lets teens imagine themselves as being more capable and powerful than their age allows in reality, an attractive illusion.
I'll add that the static quality of Tintin as a character that Vandromme identifies is dictated by the form of the series. When presented with a teenage protagonist in a work, the novelistic expectation is that what follows will be some kind of bildungsroman, where the events of the story will push the protagonist to change and mature into adulthood. However, I believe that it's a mistake to approach The Adventures of Tintin as a novel when it is fundamentally a serial - even late in his career, when he didn't need to do prepublication anymore, Hergé's approach to plot was still oriented around the page-a-week format. Serial characters, as a rule, change very little. Tintin gets compared to Sherlock Holmes more than once in the series, and it's also true on a meta level: Holmes has a few minor moments of character development, but he largely remains exactly the same over the course of Conan Doyle's stories, which were likewise published in a magazine. In a true serial, the status quo is god, because the main aim of the serial is to perpetuate itself - theoretically forever. And so Watson always finds a reason to return to Baker Street, and Tintin never gets old enough to think of settling down and getting a real job.
Like Holmes, Tintin does change and grow somewhat as a character over the course of the series, but also like Holmes, that growth is not a planned arc with an endpoint, as you would expect in a novel. Instead, it's just a result of Hergé himself maturing and changing. In his contribution to L'archipel Tintin, Benoît Peeters notes that "Grande est la tentation, pour beaucoup, de lire la série comme une totalité, un monument où tout signifierait" ("The temptation is great, for many, to read the series as a totality, a monument where everything has meaning"). And yet he declares that "si accomplies soient-elles... Les Aventures de Tintin se sont élaborées en l'absence de tout grand dessein" ("however polished they may be... The Adventures of Tintin were created in the absence of any grand design"), citing the testimonies of both Hergé and those who knew him at the beginning of the series. Hergé never really had a plan for Tintin as a character; he really did just put him in situations over and over again for a little more than fifty years. However, now that the series is only read in album format and serial publishing is less common, the "temptation" Peeters describes is even stronger. This mismatch in narrative expectations may be part of why modern readers might struggle to view Tintin as a teenaged character.
There's one more element to Tintin's strangeness: the world of the series was built around Tintin himself to facilitate his adventures. Vandromme recalls the fact, so obvious that it's easily forgetten, that "Tintin étant ce qu'il est et ne pouvant être un autre, infléchit l'intrigue d'une certaine manière. [...] Remplacez Tintin par le père Fenouillard et il vous faudra modifier l'album de fond en comble. Dans un roman les personnages déterminent les événements avant d'être déterminés par eux" (Tintin, being who he is and unable to be anyone else, influences the story in a certain way. [...] Replace Tintin with the father of the Fenouillards [character from a 19th-century comic about the misadventures of a French family abroad, n.b.] and you'll have to change the album from top to bottom. In a novel, the characters define the events before the events define them"). This point is especially relevant to Tintin given that the series' beginning was, to put it mildly, haphazard. Starting from Soviets, where Tintin is alone with his dog in a bizarre world where he can sneeze down a sewer grate, cut down a tree with a pocketknife, or fistfight a bear - whatever it takes to keep the plot moving - set a precedent for the character: that Tintin, and nobody else, will always triumph over whatever enemy or obstacle he is faced with.
Because it's founded on Tintin himself, there are no real adults in the Adventures, and in fact there can't be any. Preserving Tintin's Soviets-era boy hero status as the world of the series became steadily larger and more realistic created a kind of 'competency warp' where Tintin, along with his young "doubles," Chang and Zorrino, is effectively always the most capable, the master of the situation, while those closest to him who are much older (the Thompsons, Haddock, Calculus...) tend to act rather childishly. I think it's telling that the 1946 introduction of Blake & Mortimer is often hailed in terms like these: that "pour la première fois, les héros n'étaient pas des enfants, mais des adultes responsables dont la psychologie était en parfaite harmonie avec leurs fonctions" ("for the first time, the heroes were not children, but responsible adults whose psychology was in perfect harmony with their roles," emphasis mine). All the major adult characters in Tintin had been introduced at that point, but apparently none of them qualified as "responsible" or properly suited for their positions.
Apostolidès similarly notes a deforming effect: "Tintin est un adolescent qui, sans jamais entrer dans l’âge adulte, rajeunit le monde en se confrontant à lui. Au lieu que le personnage se soumette passivement au monde adulte, s’intègre dans une histoire, vieillisse et meure, c’est l’univers extérieur qui se fige dans le temps au contact du héros" ("Tintin is an adolescent who, without ever entering adulthood, makes the world younger by confronting it. Instead of the character submitting himself passively to the adult world, fitting in to a history, getting older and dying, it's the outside world that freezes in time at the hero's touch"). Not only does Tintin resist adulthood himself, he also protects others from its effects.
There are characters who escape the warp, but they must stay on the very edges of Tintin's orbit. One example is the efficient and no-nonsense Mr. Baxter from the Moon books. He has a real job: he's director of the atomic center, and every time we see him he's actually doing it. He also remains disengaged from the antics of the Marlinspike crew, often exasperated and confused by them. They don't belong in his serious space program, and he doesn't belong in their funny adventure series - hence the clash. Another (and very different) example is Jolyon Wagg. I wish I could remember where I read it, but I once saw it pointed out that Tintin and Wagg almost completely ignore each other; their only direct interaction in the whole series is saying hello to each other exactly once (Emerald p. 17). The unidentified author's point was that Wagg inhabits a world so intensely banal, so different from Tintin's - one with community organizations, salesman jobs, an old mother, an Uncle Anatole, a wife and (a lot of) children - that the two can't even come into contact. Wagg may be almost preternaturally obnoxious, but he's also a genuinely ordinary man in a way that the major characters really aren't.
Tintin must remain the sole and main driver of action, because if he isn't, the series would have to change fundamentally. That means no other character can threaten his role by being more competent and responsible than him - and so the adults become ridiculous and/or irrelevant, and Chang and Zorrino are only allowed to act for one album each. And yet Hergé created Tintin as a teenager, and suggested that a Tintin who progressed past teenagerhood would also grow out of adventure: "Il est difficile, pour un personnage comme ça, à le faire vieillir. Parce que s'il vieillit, il va avoir vingt ans, il va avoir vingt-deux ans, il va rencontrer une jolie fille, il va se marier, il va avoir des enfants..." ("It's hard to make a character like that get older. Because if he gets older, he'll be 20, he'll be 22, he'll meet a pretty girl, he'll get married, he'll have children..."). Tintin passing into adulthood, 'real' adulthood, symbolized here by settling down and starting a family, would make the series just as unsustainable as demoting him to a more technically age-appropriate role would; both sides of the tension between Tintin's youth and his maturity are required to make him a proper adventure hero for children.
And so he remained, as he remains today, the world's most competent teenager.
