Organised by the International Federation of Philosophical Societies (FISP) every five years in a different city -- and in Athens for the first time -- the congress was a welcome boost to the country's struggling economy, and the Greek capital which has been hit hard by anti-austerity protests.
"I'm very inspired not only by the environment, but by the people and their involvement in this congress in such a difficult period of crisis," professor Tu Weiming, head of a campaign to take the event to China in 2018, told AFP.
"Philosophy is returning to the classical Greek idea of knowing oneself, which is not only Western but is also relevant to every human being in terms of self-reflection," Tu said.
"Part of our mission is for the next congress to be held in Beijing... and I hope people will vote in favour of it," he said.
Most lectures took place at the Athens University's philosophy department on the city's leafy outskirts, but choice events were held in locations considered as hallowed philosophy ground by scholars worldwide.
These included the Lyceum of Aristotle, Plato's Academy and the Pnyx, a hill near the Acropolis that hosted citizen assemblies in classical antiquity.
"To have the congress at this time of crisis is important because it is a reminder that Greece has a huge history and heritage," said Marietta Stepanyants, a Russian professor of comparative philosophy.
"For philosophers it is something special since every place here has a special meaning to us," added Stepanyants, who is also the vice-president of the FISP congress organisers.
And for crisis-hit Greeks, "it's moral support" to be reminded of their country's special history, she said.
Event topics ranged from philosophy of politics, language, science and religion to ethics, cosmology and contemporary interpretations of the writings of Aristotle, Descartes, Heidegger, Kant, Nietzsche, Plato, Rousseau, Socrates and Spinoza.
Rediscovered in 1996, the Lyceum of Aristotle was one of three gymnasia where the city's youth received physical and mental training, learning how to become future Athenian citizens some 2,500 years ago.
It was abandoned in the fourth century AD and was unearthed in central Athens during excavation work on a modern art museum.
Archaeologists are still researching the 1.1-hectare (2.7-acre) site, which includes the remains of the Lyceum and the Palaistra -- or wrestling school -- and is still not open to the general public.
A bit further afield, some two kilometres (1.2 miles) from the city centre lies Plato's Academy, arguably the world's first university, founded in the fourth century BCE, and later shut down by the Byzantine emperor Justinian.
On Tuesday, it saw Enrico Berti of Italy analyse the contemporary relevance of Aristotle's philosophy as Japan's Noburu Notomi dissected Platonic influences in East Asia.
And at the Pnyx on Thursday, Chinese professor Chen Lai expounded on the practical wisdom in Confucian philosophy while Alexander Nehamas of Princeton University asked: "Is living an art that can be taught?".
"Confucius emphasises practical wisdom as moral action in the sense of self-transformation", whilst Aristotle's priority is perfectionism via "rationality and learning", Chen argued.
Lectures were also given on the banks of the ancient river Ilissos -- which was mostly covered up in the early 20th century -- where Socrates famously "taught that eros is love of knowledge, truth and beauty," the organisers said.
For participants, Greek as well as foreign, it was an opportunity to transcend daily troubles.
"One thing that philosophy can give us is perspective.... It emanates from ordinary life, not some special place," argues Scott Forschler, a specialist on Kant.
"Philosophy gives you the big picture, what is important beyond the daily things," he noted.
Boni admitted that philosophy may not hold answers to the crisis.
"Nevertheless, it poses questions that help clarify the situation," she said.
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