I agree with Villalobos and Razeto-Barry’s main argument that living beings are autopoietic bodies. I suggest, however, that if we apply this definition of life to a consideration of living beings as dissipative systems, we find opportunities for further refinement. I propose that living bodies are autopoietic bodies that maintain themselves by using their boundaries to control their constituent processes of dissipative adaptation.

Key words: dissipative systems, autopoiesis, living bodies.

Context: Radical constructivism claims that we have no final truth criteria for establishing one ontology over another. This leaves us with the question of how we can come to know anything in a viable manner. According to von Glasersfeld, radical constructivism is a theory of knowledge rather than a philosophy of the world in itself because we do not have access to a human-independent world. He considers knowledge as the ordering of experience to cope with situations in a satisfactory way. Problem: Von Foerster and Krippendorff show that the central goal of a constructivist theory of knowing must be to find a way of putting the knower into a known that is constructed so as to keep the knower, as well as the knowing process, viable in practice. Method: The conceptual and philosophical analysis of present theories and their necessary prerequisites suggests that such foundation for viable knowing can be built on the analysis of what the ontological prerequisites are for establishing viable observing, cognition, communication and observer-communicators, and communication media and vehicles. Results: The moment an observer chooses to accept his/her own embodied conscious presence in this world as well as language, he/she must accept other humans as partly independently existing conversation partners; if knowledge and knowing has to make sense, he/she must also accept as prerequisites for our observation and conversation a pre-linguistic reality from which our bodies come and which our conversation is often about. Furthermore, we can no longer claim that there is a reality that we do not know anything about: From being here in conversation, we know that the world can produce more or less stable embodied consciousnesses that can exchange and construct conceptual meanings through embodied conversations and actions that last over time and exist in space-time and mind, and are correlated to our embodied practices. We can also see that our communication works through signs for all living systems as well as in human language, understood as a structured and progressively developed system of communication. The prerequisite for this social semiotic production of meaning is the fourfold “semiotic star of cybersemiotics,” which includes at least four different worlds: our bodies, the combination of society, culture and language, our consciousness, and also an outer nature. Implications: The semiotic star in cybersemiotics claims that the internal subjective, the intersubjective linguistic, our living bodies, and nature are irreducible and equally necessary as epistemological prerequisites for knowing. The viable reality of any of them cannot be denied without self-refuting paradoxes. There is an obvious connectedness between the four worlds, which Peirce called “synechism.” It also points to Peirce’s conclusion that logic and rationality are part of the process of semiosis, and that meaning in the form of semiosis is a fundamental aspect of reality, not just a construction in our heads. Erratum: The paper erroneously refers to “pleroma.” The correct term is “plemora.”

Key words: ontology, embodiment, philosophy of observing, second-order cybernetics, autopoiesis, semiotics, language, phenomenology, radical constructivism, Edmund Husserl, Charles Sanders Peirce, George Spencer-Brown