This paper examines how Stanisław Lem's speculative writings configure the idea of chance as a challenge to anthropocentric thinking. Texts examined include tales from The Cyberiad, one of the faux reviews from A Perfect Vacuum, and Lem's two detective novels The Investigation and The Chain of Chance--which, as the paper argues, in fact fully participate in the same cognitive tasks that in Lem's literary-philosophical system are attributed to science fiction, concerning the expansion of possibilities of thought and the questioning, and possibly even the reinvention, of ingrained ideas and conceptions. By analysing the structural and theoretical role that chance plays in these texts, and chiefly drawing from scientific and philosophical application of probability theory, this paper demonstrates that Lem's thought and oeuvre pivot on a complex web of connections between the idea of chance, the limits of anthropocentrism, and the question of tellability. [ABSTRACT FROM AUTHOR]