Ernst von Glasersfeld in the context of "University of Massachusetts Amherst"

Radical constructivism is an approach to epistemology that situates knowledge in terms of knowers' experience. It looks to break with the conception of knowledge as a correspondence between a knower's understanding of their experience and the world beyond that experience. Adopting a skeptical position towards correspondence as in principle impossible to verify because one cannot access the world beyond one's experience in order to test the relation, radical constructivists look to redefine epistemology in terms of the viability of knowledge within knowers' experience. This break from the traditional framing of epistemology differentiates it from "trivial" forms of constructivism that emphasise the role of the knower in constructing knowledge while maintaining the traditional perspective of knowledge in terms of correspondence. Radical constructivism has been described as a "post-epistemological" position.

Radical constructivism was initially formulated by Ernst von Glasersfeld, who drew on the work of Jean Piaget, Giambattista Vico, and George Berkeley amongst others. Radical constructivism is closely related to second-order cybernetics, and especially the work of Heinz von Foerster, Humberto Maturana, and Francisco Varela. During the 1980s, Siegfried J. Schmidt played a leading role in establishing radical constructivism as a paradigm within the German speaking academic world.

Humberto Maturana Romesín (September 14, 1928 – May 6, 2021) was a Chilean biologist and philosopher. Some name him a second-order cybernetics theoretician alongside the likes of Heinz von Foerster, Gordon Pask, Herbert Brün and Ernst von Glasersfeld.

Maturana, along with Francisco Varela and Ricardo B. Uribe, was known for creating the term "autopoiesis" about the self-generating, self-maintaining structure in living systems, and concepts such as structural determinism and structural coupling. His work was influential in many fields, mainly the field of systems thinking and cybernetics. Overall, his work is concerned with the biology of cognition. Maturana (2002) insisted that autopoiesis exists only in the molecular domain, and he did not agree with the extension into sociology and other fields:

Second-order cybernetics, also known as the cybernetics of cybernetics, is the recursive application of cybernetics to itself and the reflexive practice of cybernetics according to such a critique. It is cybernetics where "the role of the observer is appreciated and acknowledged rather than disguised, as had become traditional in western science". Second-order cybernetics was developed between the late 1960s and mid 1970s by Heinz von Foerster and others, with key inspiration coming from Margaret Mead. Foerster referred to it as "the control of control and the communication of communication" and differentiated first-order cybernetics as "the cybernetics of observed systems" and second-order cybernetics as "the cybernetics of observing systems".

The concept of second-order cybernetics is closely allied to radical constructivism, which was developed around the same time by Ernst von Glasersfeld. While it is sometimes considered a break from the earlier concerns of cybernetics, there is much continuity with previous work and it can be thought of as a distinct tradition within cybernetics, with origins in issues evident during the Macy conferences in which cybernetics was initially developed. Its concerns include autonomy, epistemology, ethics, language, reflexivity, self-consistency, self-referentiality, and self-organizing capabilities of Complex Systems, such as in Complexity Theory (extenuating to the field of Complexity Economics). It has been characterised as cybernetics where "circularity is taken seriously".