Charles Peirce, Mikhail Bakhtin and Thomas Sebeok all develop original research itineraries around the sign and, despite terminological differences, canbe related with reference to the concept of dialogism and modelling. Jakob von Uexküll’s biosemiosic “functional cycle”, a model for semiosic processes, is alsoimplied in the relation between dialogue and communication.Biological models which describe communication as a self-referential, autopoietic and semiotically closed system (e.g., the models proposed by Maturana,Varela, and Thure von Uexküll) contrast with both the linear (Shannon and Weaver) and (...) the circular (Saussure) paradigms. The theory of autopoietic systems is only incompatible with dialogism if reference is to a linear causal model which describes communication as developing from source to destination, or to the conversation model governed by the turning around together rule. Dialogism understood in biosemiotic terms overlaps with the concepts of interconnectivity,interrelation, intercorporeity and presupposes the otherness relation.As Uexküll says, the relation with the umwelt in nonhuman living beings is stable and concerns the species; on the contrary, in human beings it is, changeableand concerns the single individual, which is at once an advantage and a disadvantage. Thanks to “syntactics”, human beings can construct, deconstruct and reconstruct an infinite number of worlds from a finite number of elements. This distinguishes human beings from other animals and determines their capacity for posing problems and asking questions. The human being not only produces his or her own world, but can also endanger it, and even destroy it to the point of causing the extinction of all other life forms on Earth. The unique capacity for reflection on signs makes human beings responsible for life across the planet, both human and nonhuman. Such reflections shift semiotic research in the direction of semioethics. (shrink)