"#Cybernetics might, in fact, be defined as the study of systems that are open to #energy but closed to #information and
control—systems that are “information-tight”."
W. Ross Ashby (1956): An Introduction to Cybernetics, (Chapman & Hall, London): now available electronically.
Complexity is in the eye of the beholder (observer)
Ashby: "In this book I use the words “very large” to imply that some definite #observer en, with definite resources and techniques, and that the system (is in) some practical way, too large for him; so that he cannot observe completely, or control it completely, or carry out the calculations for prediction completely. In other words, he says the system (is) “very large” if in some way it beats *him* by its richness and #complexity."
p.62
It's interesting that Ashby never uses the phrase "control system" in the book. For him, it seems, the #observer is also the (potential) #controller.