What is emergence anyway?

[Östen Dahl]

What is emergence anyway?

Recently, the terms "emergent" and "emergence" have become popular in
linguistics and neighbouring fields. Here are two representative quotations:

" 
 Hopper 
 suggested that the study of grammaticalization tended to
undermine the assumption of preexistent a priori grammatical component that
stood as a prerequisite for discourse and a precondition for communication,
and he proposed instead that grammar was an emergent property of texts.
"Structure" would then be an epiphenomenal by-product of discourse." (Hopper
1996, 231)

"If you spend some time watching the checkout lines at a supermarket, you
quickly find that the number of people queued up in each line is roughly the
same
 There is no fixed rule governing this pattern. Instead, the rule that
equalizes the number of shoppers in the various lines emerges from other
basic facts about the goals and behavior of shoppers and supermarket
managers. This simple idea of emergence through constraint satisfaction is
currently being invoked as a central explanatory mechanism in many areas of
cognitive science and neuroscience.

 the behaviors that we tend to characterize in terms of rules and symbols
are in fact emergent patterns that arise from the interactions of other less
complex or more stable underlying systems. I will refer to this new
viewpoint on language learning and processing as “emergentism”." (MacWhinney
1999)

The terms "emergent" and "emergence" however, have been around for quite
some time. In Encyclopedia Britannica's article "Emergence", the term is
said to be used in evolutionary theory in the sense of

"the rise of a system that cannot be predicted or explained from antecedent
conditions"

EB then refers to the 19th century philosopher of science George Henry
Lewes' distinction between resultants and emergents: "phenomena that are
predictable from their constituent parts and those that are not".  An
example of a resultant would be a physical mixture of sand and talcum
powder, while a chemical compound such as salt, which looks nothing like
sodium or chlorine, would exemplify an emergent.

The EB article enumerates a number of stages in biological evolution "at
which fundamentally new forms have appeared", such the orgin of life, the
origin of nucleus-bearing protozoa, and the rise of sentient beings with
nervous systems, and goes on:

"Each of these new modes of life, though grounded in the physicochemical and
biochemical conditions of the previous and simpler stage, is intelligible
only in terms of its own ordering principle. These are thus cases of
emergence."

Another presumably authoritative source is the website of the journal
Emergence: A Journal of Complexity Issues in Organizations and Management
(http://emergence.org). It declares that the idea of emergence is used in
the study of complex systems to

"indicate the arising of patterns, structures, or properties that do not
seem adequately explained by referring only to the system's pre-existing
components and their interaction."

and says that emergence is particularly important when

 "- when the organization of the system, i.e., its global order, appears to
be more salient and of a different kind than the components alone;
- when the components can be replaced without an accompanying
decommissioning of the whole system;
- when the new global patterns or properties are radically novel with
respect to the pre-existing components; thus, the emergent patterns seem to
be unpredictable and nondeducible from the components as well as irreducible
to those components."

A reader who tries to reconcile what is said about emergence in all these
quotations feels rather bewildered. In the older tradition, still
represented by EB and the journal Emergence, "emergence" stands for new and
interesting higher-order structures that are not reducible to the
lower-order ones. MacWhinney and Hopper, on the contrary, seem to use the
same term precisely for the opposite: seemingly complex systems  that are in
fact derivable from -- "epiphenomenal by-products" of -- other simpler
systems. One may ask how such a radical shift in meaning may have occurred.

It seems that we can find the seed of the conflict in the original notion of
emergence. On one hand, the target has new and interesting properties that
cannot be described in terms of the source, on the other, there is
presumably some kind of causal chain that leads from the source to the
target. The essence of the notion of a self-organizing system seems to be
precisely the fact that unexpected things happen as it were by themselves.
Depending on whether one is more fascinated by the novel or the predictable
component in this process, one may come to see different and seemingly
contradictory aspects of "emergence" as criterial. Hopefully, we will
eventually be able to see both sides of the phenomena at the same time.

REFERENCES

Hopper, Paul J. 1996. Some recent trends in grammaticalization. Annual
Review of Anthropology. 25:217-36.

MacWhinney, Brian. 1999. Emergent Language. In M. Darnell, E. Moravcsik, F.
Newmeyer, M. Noonan, and K. Wheatley, eds. Functionalism and Formalism in
Linguistics. New York: John Benjamins.

-----------------------
Östen Dahl
oesten at ling.su.se
http://www.ling.su.se/staff/oesten/oesten.htm