In appreciating the systems sciences, it can be important to appreciate distinctions around the producer-product relation and coproducers.  A system — which is conceptually bounded by observer(s) defining a boundary — does not exist independently of its environment.  A system may draw on inputs or resources in its environment.  Changes in the environment may be associated with reactions, responses or proactive reformation (i.e. changes in structure(s)) or transformation (i.e. changes in structure(s) and function(s)).

The most rigourous description of these distinctions is in Ackoff and Emery (1972), but this is a derivation of Ackoff’s original dissertation, and relatively difficult to read.  I happened across a more readable, and helpful summary in Ackoff (1981).

The Machine Age’s commitment to cause and effect was the source of many dilemmas, including the one involving free will. At the turn of the century the American philosopher E. A. Singer, Jr., showed that science had, in effect, been cheating.  It was using two different relationships but calling both cause and effect.  He pointed out, for example, that acorns do not cause oaks because they are not sufficient, even though they are necessary, for oaks.  An acorn thrown into the ocean, or planted in the desert or an Arctic ice cap does not yield an oak.  To call the relationship between an acorn and an oak ‘probabilistic’ or ‘non deterministic causality,’ as many scientists did, was cheating because it is not possible to have a probability other than 1.0 associated with a cause; a cause completely determines its effect.