Until recently, there was a small number of acknowledged truths about second-row forwards: Springbok locks were always horrible (think Moaner van Heerden); the New Zealand variety were always tougher than they looked (the spindly Ian Jones was a classic example); the human tractors in the French engine room were congenitally incapable of jumping at line-out time, unless it was downwards.
It was also assumed that the best partnerships brought opposites together: a footballing high-roller on one side of the scrum; a troglodyte enforcer on the other. The dream combination of the modern era would have seen the Australian genius John Eales paired with Martin Johnson of England. Eales would have done the running, passing, ball-winning, try-scoring and goal-kicking. Johnson would have done the important stuff.
One last thing. Leaving aside Eales, who was making match-winning tackles in World Cup finals at the tender age of 21, international locks were meant to look old beyond their years, having served a long and brutal apprenticeship in the darkened recesses before even thinking about winning a Test cap. It is safe to say that Joe Launchbury, the newest member of the England pack, has sent that particular truth spinning into the realm of myth.
A mere 40-odd games into his professional career – a single season's worth of top-level activity, more or less – the 21-year-old Devonian can claim to have fought a battle royal with the South African forwards and come out with a smile on his impossibly fresh second-rower's face, seen off the world champions from New Zealand in some style and helped stare down the Irish pack on a gruesome afternoon in Dublin.
By his own admission, it has been an astonishing few months – and that's just on the red-rose front. At club level, he was one of a group of largely untested players directly responsible for saving Wasps from relegation, and perhaps extinction, last term. "Maybe that stupid old line about everything happening for a reason is right," he says, recalling that desperate period at Adams Park. "I don't think I'm exaggerating when I tell you that if we'd gone down the club would have struggled to remain in existence, so those were tough times. There were moments when you asked yourself: 'How can this be fun? How can you get up in the morning and look forward to going to work?' But I loved it. Looking back, playing under that kind of pressure gave me some great building blocks on which to construct my game.
"Now, things have changed completely at Wasps, and the England experience continues to be brilliant. Suddenly, I'm playing front-foot rugby for two winning teams and it's a fantastic feeling. A year's a long time in this game, I think."
Launchbury was not the only England player who, in travelling to Ireland last weekend, faced a physical, psychological and emotional examination above and beyond anything he had previously experienced. The hooker Tom Youngs fell squarely into the same category, as did the centre Billy Twelvetrees and the full-back Alex Goode. It is, however, difficult to imagine that anyone took more from the experience than the lock did, even though he was replaced by the Northampton forward Courtney Lawes, that most incendiary of open-field hit-men, shortly after the interval.
"The tension in the build-up, the passion that was generated as we moved towards kick-off…you don't necessarily get it to the same degree when you're staying at the Pennyhill Park [the country estate hotel in Surrey that doubles as the England base] and driving up the road to Twickenham," he remarks. "It felt like a really hard game, but that was the side of it I really enjoyed.
"Was it difficult, being replaced? Look, you always want to stay on. But the fact of the matter is that this England squad has a lot of strength. I knew Courtney was right there, waiting to play a part. He's always there, waiting for an opportunity, and he always makes an impact when he's given the chance. I understood the situation. The way we managed the game after James Haskell was binned and we went down to 14 men was testament to how the coaches used the bench."
Lawes will be in the frame for selection when Stuart Lancaster and his fellow selectors meet on Tuesday to finalise the line-up for next weekend's mid-point championship meeting with France, but with the odds heavily in favour of an unchanged side, Launchbury is a warm favourite to face Les Bleus for the first time. "I've had some European club games against French teams and I went up against their Under-20s at the Junior World Cup in 2011, but my real memories of them are as a spectator, watching them beat the best. I don't want to see them do it as a player, that's for sure."
Assuming he is picked alongside the increasingly influential Leicester lock Geoff Parling for a fifth straight international, he will not be turned to stone by the shock of the new. Far from it. Launchbury has had his share of disappointments – he found himself stacking shelves in a far-flung corner of Sussex when the men running the Harlequins academy decided, in a rare misjudgement, that he was unworthy of a full-time contract – but from the moment Wasps took the opposing view and asked him for his thumbprint, he has never doubted himself.
"I don't think I've questioned myself since I signed that first pro deal, when I was 17 or 18," he says, without the merest hint of arrogance. "Each time I've taken a step up – first England age-group cap, first Premiership game, first international – I've felt prepared for it. Nothing has come as a shock, although the physicality is greater each time. On every occasion, I've gone in thinking 'I can handle this'.
"And to be honest, there hasn't even been much chat from the opposition about my age. I don't feel massively young, probably because the whole game is getting younger nowadays. Nobody has made me feel like a boy amongst men."
At Wasps, he has quickly established himself as one of the main men, and he takes the role seriously. He will be back at Adams Park tomorrow to watch the Premiership game with Gloucester before checking into the Pennyhill for another few days of training-field purgatory. "It's fourth versus fifth and a big match; if we can win, we'll open up some distance in the table," he says, in tones that suggest he never dreamt of being anywhere else on his day off.
Interestingly, he credits David Young, the former Wales and Lions prop who joined the club as director of rugby at the start of last season, with helping him grow up fast. "When we were in deep trouble a few months ago, Dai was the one who had our backs," he recalled. "It was tough for him: he'd been dealt a rough hand, just as we had. But he showed us what it meant to look after each other in a fight for survival. He's a fantastic guy, an inspiration."
In those difficult days, Launchbury played on the blind-side flank at least as often as he played at lock, and that flexibility marks him out as something of a new-age No 4. The All Blacks have long embraced the idea that as the modern game places ever greater emphasis on pitch coverage, the lean, mean and mobile will inevitably trump the supersized and leaden-footed. Maximum power and dynamism in an aerodynamic frame is rugby's "new now".
"These days, it's not necessarily the biggest guy, the heaviest guy who wins," he agrees. "It's all about work rate. It's about how many involvements a player has over the course of a game. There again, don't the French have some 22st monster coming off the bench at the moment?" Not any more, they don't. The gigantic Romain Taofifenua has been dropped from the squad for next week's contest as Philippe Saint-André, the Tricolore coach, gets with the zeitgeist.
Not that the prospect of tangling with Taofifenua would have deprived Launchbury of his beauty sleep. He is too busy enjoying life. "There's no time to step back and reflect on what's gone on over the last year," he said, "so I've given up trying. I'll wait until I have a few weeks off in the summer. Then I'll feel pretty proud, I guess."