Homo Ludens is the Latin term, in relatively simple terms, for 'the playing man'. This means that 'play' is a key part of how people develop, without it necessarily having to be for any particular purpose other than personal use.
But if you're good enough at 'playing', you can eventually go far in life on the basis of that quality.
Albert Gronbaek is a prime example of what that means, and the rest of European football is beginning to realise this after his big move from Bodo/Glimt in the Norwegian Elite League to Rennes in Ligue 1.
With an estimated price tag of 12 million euros, it's the biggest ever transfer from the Norwegian league. But it could quickly turn out to be a bargain of sorts for the midfielder, who is also on his way to a breakthrough with the Danish national team, who have long been looking for someone like him.
Ever since Gronbaek stepped into his first pair of football boots in the Aarhus suburb of Risskov, it was clear that we were dealing with a special talent, especially because the youngster obviously had strengths in playing with the ball.
And while at the time it was only the coaches at Aarhus clubs VRI and then AGF who could see Gronbaek's potential, it has also become clear to the rest of Denmark, and Europe for that matter, over the first two matches of this season's Nations League.
These games saw Gronbaek make his international debut, before scoring his first goal for Denmark in the 2-0 win over Serbia. Before that, he had been named Man of the Match in his debut against Switzerland.
This was partly due to his incredible ability to quickly turn towards a defence and take on up to several players at a time, driven by a wild confidence in his play.
Denmark's 'missing link'?
A skill that the Danish national team has lacked for many years, the kind of ability that can open up matches that otherwise seem deadlocked - as was the case in the first half hour against Serbia.
Combined with a well-developed ball-striking technique that allows him to both finesse the ball calmly but also fire thunderbolts, he is also a major goal threat while having a good eye for his teammates.
His ability to drift from left to right and vice versa was on display for Rennes fans in Gronbaek's first game in Ligue 1, where they beat faded giants Lyon 3-0 at home and the Dane played 87 minutes, repeatedly demonstrating his consistent attacking mindset.
He was initially positioned on the right side of the attack in both international matches, but he had apparently been given quite free rein to move across the pitch, which also led to his goal against the Serbs, where he pulled in from the left side of the pitch.
But Rennes didn't buy him just for his ability, but also because of his great end product. Last weekend, he scored his first goal for the club bagging against Montpellier.
When Gronbaek made his move to Bodo/Glimt in early 2023, it was the start of an extremely productive phase for the offensive player, who delivered plenty of goals and assists.
Not only in the Norwegian top flight, where he was voted the best midfielder of 2023, but also in European competitions, where he made a name for himself in Bodo's Conference League matches.
The standout moment was Gronbaek's performance against Ajax in the Conference League, where he scored both of Bodo's goals in the 2-2 draw at Johan Cruijff Arena, scored an impressive 8.7 on Flashscore's ratings and was also named Conference League Player of the Round.
Even though Bodo lost the return leg in Norway 1-2 (where Gronbaek received two yellow cards and was sent off), it was still a performance that caused a stir around Europe. It was also a fine demonstration of Gronbaek's excellent ability to operate in small spaces and play a one-two game with his teammates.
An ability that was emphasised by the beautiful 1-0 goal against Serbia, where Yussuf Poulsen beautifully acted in support of the Dane, who eventually chipped the ball past Serbian goalkeeper Predrag Rajkovic.
In stature and playing style, he resembles another former AGF legend, Martin Jorgensen, who had a brilliant career in Serie A with Udinese and Fiorentina.
But Gronbaek has a more direct approach to his game, which in the long run will most likely produce more goals than Jorgensen managed to do during his career, where he developed into a high-calibre playmaker and passer.
Better 'playmates' await
It is said of the concept of 'homo ludens' that play is an end in itself and that it brings out the most creative parts in people. However, it is also said to be something you lose as a human being the older you get.
This is unlikely to happen to Gronbaek, who seems to get better and better the more he plays on the pitch.
Of course, bringing out the best in a player like Rennes' new star also requires good 'playmates', but it seems unlikely that he has yet reached his peak in terms of the calibre of players he can play with.
For now, it's Rennes and the Danish national team, where he has established himself as a new fan favourite in record time.