Ayten's notion of entailment is accurate in depicting
entailment as sort of a form of "causal potential" although there is more
here than this. All causality is just a tiny fraction of the total potential
entailed by systems and their interactions. Entailment is also independent of
time or directionality, in that separate things (parts, components,
stages, interactivity, etc) can both entail/be-entailed-by one
another in totality, but not necessarily directly or
specifically (like the chicken and the egg). Causality is dependent on
time flow, among other things, where entailment is not.
Entailment describes relations, including potential, in totality.
Causality describes what happens. In this way, causality can be seen
as a subset of the total entailment potential of systems and can be used
to try to learn about the entailment relations within system organizations. It
is entailment that Robert Rosen was most seeking to understand because
it would include causality (and inference, as well-- which describes the
version of entailment expressed in modeling/simulations) within it. Entailment
is the more comprehensive category.
It's sort of like a situation where your pet dog reacts to
some new stimulus in ways you've never seen it behave before. Extreme
heat, extreme cold, earthquake, weather, whatever... The entailment was
always present, but this is the first causal example.
There have been cases of organisms that were thought to be fully
understood, only to have it suddenly become manifest that what we've seen is
only a very long larval stage and the organism undergoes a sudden
metamorphosis to reach some new stage (which we presume is the adult). The
Axolotl, of Mexico, was one such organism. It developed the capability of
breeding while still in its larval stage, a fairly well-known phenomenon
(neotony). In this case, the lakes where this salamander species lived was at
very high altitude. When taken to lower altitudes, the axolotls began to
metamorphose into a fairly ordinary salamander species.
My father was fascinated by the axolotl because he said it had
far more biological capability in its larval stage, which it lost when it
metamorphosed. For example, in the larval stage it can breathe air or use its
gills in an aquatic environment. It can completely regenerate an
entire limb if cut off. In its natural environment, the axolotl never
actually fulfills its entailed metamorphosis from larval stage to adult stage,
living its entire life in the larval stage. Thus, entailment and causality
diverge in the same species.
My father actually wrote a fictional short story based on this
phenomenon, entitled "What Really Happened To Jeff" or something like that,
where the main character is a college student whose roommate was experimenting
on axolotls and developed a theory that our current human form may just be a
case of arrested development in the larval stage. He figured out how
to trigger it and disappeared without a trace with no clues as to what could
have happened to him (except for the dessicated sea squirt found
lying on the floor of the lab...).
Entailment is what is responsible for side effects; the so called
"hidden variables" or unknown relations within a system being
studied.
Judith