"A living system, due to its circular organization, is an inductive system and functions always in a predictive manner: what happened once will occur again. Its organization, is conservative and repeats only that which works. For this same reason living systems are historical systems; the relevance of a given conduct or mode of behavior is always determined in the past."

“Living systems are units of interactions; they exist in an ambience. From a purely biological point of view they cannot be understood independently of that part of the ambience with which they interact: the niche; nor can the niche be defined independently of the living system that specifies it.”

“The official site of Humberto Maturana”

“Man knows and his capacity to know depends on his biological integrity; furthermore, he knows that he knows. As a basic psychological and, hence, biological function cognition guides his handling of the universe and knowledge gives certainty to his acts; objective knowledge seems possible and through objective knowledge the universe appears systematic and predictable.”

“I maintain that learned orienting interactions, coupled with some mode of behavior that allowed for an independent recursive expansion of the domain of interactions of the organism, such as social life... and/or tool making and use, must have offered a selective basis for the evolution of the orienting behavior that in hominids led to our present-day languages.”

“We say that the words were smooth, caressing, hard, sharp, and so on: all words that refer to body touching. Indeed we can kill or elate with words as body experiences. We kill or elate with words because, as co-ordinations of actions, they take place through body interactions that trigger in us body changes in the domain of physiology.”

“Coherence and harmony in relations and interactions between the members of a human social system are due to the coherence and harmony of their growth in it, in an ongoing social learning which their own social operation defines and which is possible thanks to the genetic and ontogenetic processes that permit structural plasticity of the members.”