1.

N. Luhmann writes: "Since the early 1980s it has become increasingly clear what significance the comparability of functional systems has for social theory" (12), especially because it has become clear that it is not possible to deduce society - as a whole - from one principle.

2.

Cybernetics and systems theory is often referred to as "interdiciplinary". Firstly, because the mathematician N. Wiener worked together with the physiologist A. Rosenblueth and the electrical engineer J. Bigelow in the development of cybernetics; secondly, because cybernetics is used as a method in various sciences. Cybernetics is a teaching and as such, of course, it is as little interdisciplinary as mathematics. Interdisciplinary are at best research groups that use cybernetics. Cybernetics - and the systems theory that follows it - can be used wherever constructive explanations are sought.

3.

H. von Foerster headed an institute for the research of biologically based computers, which he called Bio-Lab. To this day it has not yet been proven to what extent he was ahead of his time, but useful computer technology was hardly developed there. So to speak, as a by-product of the occupation with rather complex systems, what he had published under view and insight, became the basis of radical constructivism.

4.

I refer the term "autopoiesis" to a theory which says something - according to N. Luhmann very little - about the emergence of autopoietic systems. So I call autopoiesis a certain conception or explanation, but not the fact that living beings create themselves. H. Maturana's famous single-cell organism, which - like Baron von Münchhausen much later - pulled itself out of the primordial soup by making a skin that separated it from the primordial soup, exists through H. Maturana's autopoietic view. I do not believe that the unicellular organism knows anything about autopoiesis or has behaved according to this theory. But I explain my perception of its existence by the autopoietic theory.

5.

N. Bischof presented J. Piaget's work through R. Hirsig's systems theory, thus showing the extent to which J. Piaget thought in terms of systems theory Finally, central concepts of J. Piaget such as assimilation - which he had developed before cybernetics - were accommodated by systems theory.

6.

E. von Glasersfeld called his radical interpretation of J. Piaget's work "Radical Constructivism". In the discourse on Radical Constructivism, it is often disputed whether there is a reality. I find that a completely pointless question. I will replace it with some other questions that I think fit much better to Radical Constructivism.