By variously drawing from the philosophical tradition, many authors belonging to the so-called “phenomenological movement” have thought appropriate to thematize the relationship between the (apparently ludic) activity of playing games and the (allegedly serious) philosophical attempt to make sense of the world. Franz Brentano, for instance, was not only a major chess player and published author of riddles, but also a reader of Heraclitus’s fragments in which the world is compared to the play of a child. Husserl has firmly maintained that the crisis of Pre-Socratic cosmologies, the birth of Plato’s genuine philosophy and the first breakthrough of transcendental thinking are momentous side-effects of one major event in the history of philosophy, i.e. that of the Sophist “playing the game of philosophy”. While discussing Kant’s existential concept of the world, Heidegger has plainly stated that the world has “the character of play”, while, drawing from Descartes and the Stoics, Sartre has taken the activity of playing as evidence for the existential freedom of human consciousness and its power to transcend the reality of the world as it is. Finally, Eugen Fink has gone as far as to develop not only a phenomenological anthropology in which “play” is a “fundamental phenomenon of human existence” (together with “death”, “labour”, “fight” and “love”) but also a full-fledged metaphysics, entirely revolving around the idea of the “play as a world-symbol”, and opposing Plato’s understanding of ludic activities to the importance of Heraclitus’s world wisdom. In this seminar we will try to 1) present some of these views, 2) expound their driving motives, 3) see how they differently refer to the philosophical tradition (Heraclitus, Plato, Gorgias, the Stoics but also Descartes and Kant), 4) draw a map of their possible connections and 5) question the reasons and significance of thinking the “world” as a phenomenological concept from the standpoint of the “play”.