In The Tree of Knowledge: The Biological Roots of Human Understanding, Maturana & Varela write,
Ontogeny is the history of the structural changes in a particular living being. In this history each living being begins with an initial structure. This structure conditions the course of its interactions and restricts the structural changes that the interactions may trigger in it. At the same time, it is born in a particular place, in a medium that constitutes the ambience in which it emerges and in which it interacts. This ambience appears to have a structural dynamics of its own, operationally distinct from the living being. This is a crucial point. As observers, we have distinguished the living system as a unity from its background and have characterized it as a definite organization. We have thus distinguished two structures that are going to be considered operationally independent of each other: living being and environment. Between them there is a necessary structural congruence (or the unity disappears). In the interactions between the living being and the environment within this structural congruence, the perturbations of the environment do not determine what happens to the living being; rather, it is the structure of the living being that determines what change occurs in it. The interaction is not instructive, for it does not determine what its effects are going to be. Therefore, we have used the expression “to trigger” an effect. In this way we refer to the fact that the changes that result from the interaction between the living system and its environment are brought about by the disturbing agent but determined by the structure of the disturbed system. . . .
The key to understanding all of this is indeed simple: as scientists, we can deal only with unities that are structurally determined. That is, we can only deal with systems in which all their changes are determined by their structure, whatever it may be, and in which those structural changes are a result of their own dynamics or triggered by their interactions. . . .
Thus, we all reasonably suppose that lead bullets fired at someone at point-blank range trigger in the victim destructive changes specified by the structure of that person. As we all know, however, those same bullets are mere perturbations to a vampire. He required a wooden stake in this heart before he undergoes a destructive change. (95-99)
I wrote about these ideas in one of my first blog posts, in which I discussed the interaction between the United States Department of Justice and Apple, Inc. The DOJ can trigger responses in Apple, Inc., but the nature of those responses is structurally determined by Apple.