If a tree falls in the forest and no-one is around to hear it, does it make a sound?
The question posed above is a famous exercise in experimental thought, challenging readers to consider existence as a mere sensation that without our own perception has no inherent meaning or value.
Paris Saint-Germain's Brazilian goal machine Neymar is in a similar quandary. He may break all scoring records this season in Ligue 1 – but if the football world responds with a yawn and a raised eyebrow, what does it even mean for the ex-Barcelona star?
Goals certainly have been flowing freely for Neymar since his world-record, €222 million move to Parc des Princes.
A tally of 28 in all competitions during his debut season marked the striker's third-best haul in European football, a mark that is even more admirable when one considers that his campaign was cut short as early as February due to a metatarsal problem.
With two goals in as many Ligue 1 games this term , too, a repeat of 2017-18's numbers or something even more impressive is well within reach. The problem Neymar is facing is not a lack of form on the pitch, but rather that few outside Paris seem to care.
Even in his home nation, where the name Neymar has been elevated to almost demi-god status since he burst onto the scene as a teenager with Santos, indifference seems to be growing.
The current Ligue 1 season will not be transmitted anywhere on Brazilian television, leaving fans largely in the dark over their hero's exploits.
The French top flight, meanwhile, is greeted almost as a joke around Europe, as rightly or wrongly it is perceived as Paris' aristocrats strolling to victory against the disorganised rabble that makes up the rest of the league.
Only Champions League victory, a scenario that looks highly unlikely to say the least given PSG's mediocre track record in the competition, would restore the star to the position his undoubted talents merit.
Within the City of Love, Neymar also faces a challenge to his status as standard bearer of all things PSG.
It is Kylian Mbappe, the young upstart who now boasts a World Cup winner's medal – something that has to date eluded not just Neymar, but also inveterate Ballon d'Or rivals Cristiano Ronaldo and Lionel Messi throughout their careers – who looks set to be the darling of the Parc des Princes this season as he goes from strength to strength.
Mbappe is the golden boy of French football, his team-mate the pricey, high-strung mercenary who reportedly clashed with everyone but the PSG lunch lady during his debut season.
Having spent so long under Messi's daunting shadow at Camp Nou, Neymar is now in real danger of finding himself in another, unforeseen supporting role.
There is, however, another way. Over in Madrid one particularly prestigious club is in dire need of a hero, having seen two idols depart over the summer.
A punishing UEFA Super Cup defeat to city rivals Atletico showed that the departures of Zinedine Zidane and Cristiano Ronaldo are also likely to leave their mark on the pitch, while the shouts rise for Florentino Perez to add a new Galactico to Real's ranks.
The arrival of Neymar through the Santiago Bernabeu gates would be just the ticket for the Merengue's famously restless supporters, and give the player the stage he so craves in the process. And it may not be too far off.
“For now, I must believe in his own words about staying at PSG, but from what I've heard, he will end up - sooner or later - at Real Madrid," opined Brazil legend Rivaldo when asked by Betfair whether he saw Neymar at the Bernabeu. Former PSG team-mate Yuri Berchiche went even further to El Larguero: "I see him returning but more in white than in blue and red.
"He was very happy at Barcelona. He still likes La Liga because I spoke with him about it, we have a good friendship, and he's a fantastic person. If he joins Madrid I wish him the best of luck."
Such a move would logically not come cheap. Having broken the transfer record last summer, Neymar would shatter it once more with his prospective return to La Liga, with a fee of €300 million mentioned widely as the price PSG would insist upon for any deal to be struck. Madrid would also have to accommodate the striker's astronomical wages, set currently at €700,000 a week and only likely to rise.
But as Madrid have shown countless times over the years, you cannot put a price on prestige.
Neymar may not arrive in this transfer window, perhaps not even next summer; but at this point it seems inevitable that one day we will see the star pull on the famous white jersey and strive to become the darling of the Bernabeu as he once was at Camp Nou.
Neymar also has everything to gain from such a move, the next logical step to free him from the obscurity of Ligue 1 and ensure that when he hits the net, the whole world is there to hear it.