Beyond the genotype/phenotype: complexity and self-referentiality A view is presented, inspired by Rosen (2000), in which complexity is defined by the existence of mutually entailed loops that lead to a, paradoxical circular thought as it is found in the genotype-phenotype interrelations. It is, thus, shown a parallel between Newtonian inertial/gravitational mass duality and Mendelian-Wiessmanian genotype/phenotype duality. The latter inspires the linear non-circular presentation of molecular biology central dogma that does not question the origin of genetic information, in the same way as Newton left unexplained the nature of ’force’. To clarify this perspective, it is explained how the Lamarckian discourse that led to the foundation of biology was precisely addressed to answer the question about the nature of forces. Even if this approach was found to be incorrect, Lamarck made explicit the presence of the self-referential loop that later on was removed by the incorporation of the genotype-phenotype duality in which the former assumed the determinant role. Despite the advances of molecular and developmental biology the paradoxes appear over again as an indication of an unavoidable property of natural systems that goes beyond the genotype-phenotype duality as an indication of a profound irreducible unity in physical systems, both living and non-living. Key words: Genotype/phenotype, self-referential loop, inertia, paradox, complexity, system, Aristotelian causes, central dogma, mechanisism, force, genetics.