There are so many positions on a rugby field that require that the incumbent must know exactly what he is up to. Second-row requires a lot more ability than you might think.
If you had never set foot on a rugby pitch or even watched a game of Union, how many weeks or months would it take to learn what to do and how to do it in a scrum?
Then, when you have mastered it on the right hand, try it out on the left-hand side. It is not like playing golf left-handed if you are naturally right-handed, but winning lineout ball - how long before you get it right?
How about catching one of those steepling drop-outs when the match starts?
When exactly is it that you tell your lifters to lift you into the sky?
Are you absolutely certain that you are standing in the exact position that the ball is going to land in?
Do you know exactly what you are doing in the middle of a maul as it splits right? What angle should you take to clear out a ruck? Tackling? Carrying? Passing? Pressing? Any of you know exactly what to do?
Donkeys? Is that what you call us? And yet as a second-row you really are just a general operative. The skill guys? The specialists!
Now hooker, that really is a specialist position. Throwing in and hooking require a huge skill and accuracy quotient. Bravery too! When a scrum goes backwards, your back-row often just get up and watch their team-mates get forced into the mud.
The second-rows can escape injury as the flesh pile collapses on top of them, but the hooker is bound to his props - he has no way of being able to cover himself. I generally think you have to be certifiable to play there.
All around the park - particularly at the highest level - you really do need to know exactly what you are doing. Nowadays conventional wisdom dictates to us that the number on your back is just a number - trotted out by people who haven't a clue.
Rugby is a game for specialists - every now and again a player can change wings or a centre can move out one. Deep down, though, when a player says he would play in any position that he is picked for, he doesn't really mean it.
Back in 2009, Nick Mallett, of all people, decided to play his star openside flanker Mauro Bergamasco at scrum-half. It was a feckless indulgence - particularly as their opponent was England and Bergamasco was put out of his misery one minute into the second half.
Good players can give passable impressions if they get thrown into unfamiliar positions. In the pressure cooker moments they are often exposed. No.8 is a position which requires instinct and guile. Quite often the smartest player in the pack is the No.8. That said, some that I played with would have had to have been watered twice a week.
In the last generation of No.8s, we had a golden era of Sergio Parisse, Kieran Read, Imanol Harinordoquy and Jamie Heaslip.
All represented their countries for over a decade with distinction. The cupboard looks a bit bare at the moment. If you need any evidence, track Scotland's Nick Haining for a few minutes in his next Test match - if he gets one.
I kept an eye on Taulupe Faletau at the Aviva last Saturday. The Welsh No.8 has had a rough two years since he starred in the 2017 Lions series in New Zealand.
A fractured arm and a broken clavicle meant he played very little rugby in 2018 and 2019. Wazza didn't bring him to Japan but he has kept going, and if Wales were to do something last Saturday the impetus would have come from the Tongan-born Bath man.
Faletau got involved but was a bit off the pace. Even though he is incredibly still only 29, he looked like he was 40.
Faletau may just play himself into form by the end of the Championship but is likely to be outshone by the highly impressive, all-purpose Gregory Alldritt.
The Frenchman really does seem to be a master of all trades and he was one of the key differences in the France v England game.
Eddie Jones promised there would be "absolute brutality" in that match. That would have been so if the Vunipola brothers were playing and Manu Tuilagi had lasted more than a quarter. England looked a bit threadbare when it came to horsepower and were horribly exposed in their back-row make-up.
Sam Underhill and Tom Curry had great World Cups until the final. Maybe you can look better than you are when the Billy Vunipola express is charging over the gain-line.
Curry is a very good openside wing-forward. A specialist wing-forward who, even at the tender age of 21, knows all the angles and all the short cuts.
Tom Curry, however, is not a good No.8. He is not a physically imposing player who can cart the ball forward. Billy Vunipola is a rare breed that can take contact on his terms, even if he himself is on the back foot.
Simple things like control at the base of the scrum, knowing when and how to pick. Even a simple 8/9 from the base needs proper timing.
Curry is a good runner, but he is a fetcher by trade and does not have the physical personality to play at No.8, and for Jones this is an indulgence similar to Mallett's folly.
CJ Stander had a very effective 79 minutes last Saturday and there may be a temptation to play him again in that position.
Caelan Doris seems to be primed for a return against England in 10 days' time. We may be kidding ourselves that Doris may force his way around south-west London like a galloping stallion. Unfortunately, in Twickenham most galloping stallions have chariots attached.
Ireland will have an advantage if they pick a specialist No.8 for the game. Curry may learn eventually the nuances of the position, but Jones would be far better off picking Alex Dombrandt, a specialist No.8 and a powerhouse who would cause Ireland no end of trouble.
Say nothing and let Eddie indulge himself!