Argentinean narrative of the "metaphysical fantastic" is a good stage to illuminate the key points in the debate on post-modernity. I understand post-modern subjectivity as a sense of incredulity about " metanarratives" (Lyotard), then, the crisis of knowledge of the main character in Las Ruinas Circulares can be read as a symptom of the death of the Cartesian subject (Trías) or of mourning of the metaphysical thinking (Moreiras). This hypothesis can be sustained on the fact that the motive of the dreamis framed within the utopian project of the modern instrumental reason. Two antagonistic processes take place in this knowledge journey of modern subject. One is an attempt of symbolic construction, to dream of and to materialize a utopia for mankind. The other is the allegoric destitution of the man that dreams and of his utopian project. The fantastic in this narration as long as it emerges as carried out through the motive of an infinite chain of dreams, inscribes itself within an aesthetic of the sublime.