In his second book on being and event, Logics of Worlds, Alain Badiou describes Plato’s late dialogue, The Sophist as “one of the first transcendental inquiries in the history of thought”. In this dialogue, Plato introduces what he calls the Idea of the Other, the possibility of a being of non-being, an inevitable break with the Parmenidean tradition. However, according to Badiou, Plato fails to provide an example of how this Idea of the Other can manifest itself or be effective in a world, or in other words, appear. This paper argues that not only there is such an example in Plato’s Sophist, namely, the phantasma, but also that it can be strongly related to Badiou’s philosophical system.In his second book on being and event, Logics of Worlds, Alain Badiou describes Plato’s late dialogue, The Sophist as “one of the first transcendental inquiries in the history of thought”. In this dialogue, Plato introduces what he calls the Idea of the Other, the possibility of a being of non-being, an inevitable break with the Parmenidean tradition. However, according to Badiou, Plato fails to provide an example of how this Idea of the Other can manifest itself or be effective in a world, or in other words, appear. This paper argues that not only there is such an example in Plato’s Sophist, namely, the phantasma, but also that it can be strongly related to Badiou’s philosophical system.