This article looks at the duplicity as the most important poetics’ component of Stanislaw Lems’ novel “Eden”. In the characters’ system special attention is paid to the dialectical features of the main characters’ relationship. The diffusive peculiarities of the novels’ duplicity which are the merging of antagonistic and twinned duplicities’ types is also under analyses. The scientific research defines the duplicity between different characters, describes the motif texts’ contract as consequence of the motif levels’ duplicity and emphasizes the duplicities’ influence of the philosophical novels’ component. In conclusion the importance of duplicity for determining the differences and similarities of characters’ psychology and for describing moral and ethical problems is emphasized.