Stigmergy, You Say?

“Every aspiring young materialist dreams of growing up to be a robot.”

Roland, as transcribed by David Bentley Hart

First Things, February, 2015

Or a termite?

One of the disappointments of David Bentley Hart writing much less for “First Things” is that I no longer get to enjoy the late-night wisdom of his dog, Roland.  That line above has stayed with me for several years and it comes to mind repeatedly when I think about stigmergy.

I don’t remember by what chain of Wikipedia searches I first came across the term “stigmergy.”  I was reading about termites but – why?

Here are some definitions of stigmergy, all from the Wikipedia article:

  

Stigmergy is a consensus social network mechanism of indirect coordination, through the environment, between agents or actions. The principle is that the trace left in the environment by an action stimulates the performance of a next action, by the same or a different agent. In that way, subsequent actions tend to reinforce and build on each other, leading to the spontaneous emergence of coherent, apparently systematic activity.

Stigmergy is a form of self-organizing social network. It produces complex, seemingly intelligent structures, without need for any planning, control, or even direct communication between the agents. As such it supports efficient collaboration between extremely simple agents, who lack any memory, intelligence or even individual awareness of each other.

The term "stigmergy" was introduced by French biologist Pierre-Paul Grassé in 1959 to refer to termite behavior. He defined it as: "Stimulation of workers by the performance they have achieved." It is derived from the Greek words στίγμα stigma "mark, sign" and ἔργον ergon "work, action", and captures the notion that an agent’s actions leave signs in the environment, signs that it and other agents sense and that determine and incite their subsequent actions.

When thinking about termites – for whatever reason – or ants or other hive creatures, this idea of simple agents leaving unintentional signals for each other that trigger follow-up actions is a reasonable hypothesis.  That is, a hypothesis to account for seemingly intelligent structures without a termite architect and a termite foreman.

Darwin came at this question from a different angle in “Origin of the Species” while considering slave-master ants.  There are ants that carry off pupas after a successful raid on a target colony.  They hatch them back home and the foreign ants become workers in their captor’s colony.  How did this come about?  Darwin did not know for sure, but applying the idea of natural selection -- the idea that variation produces tiny advantages and disadvantages for species, which advantages accumulating over many generations lead to significantly improved adaptations (and the disadvantages lead to fewer offspring and perhaps extinction) – he wondered if long ago some of the pupas carried home as food hatched instead.  In some instances the foreign ants would have fought or been killed out of hand.  In the range of variation, in some colonies they would have survived.  These colonies, having the advantage of additional workers, might have gained a survival advantage and their behavioral adaptation could have become dominant in the species.  (This is all supposition and this series would have relied on further, related adaptations.)

As a matter of fact, the whole idea of natural selection seems “stigmergic” once you think about it.  But that’s not why I think about it.

I think about stigmergy because I come across attempts to explain intelligence, or find ways to mimic intelligence, through “self-organizing” non-deliberate mechanisms.  From the Wikipedia stigmergy article:

On the Internet there are many collective projects where users interact only by modifying local parts of their shared virtual environment. Wikipedia is an example of this. The massive structure of information available in a wiki, or an open source software project such as the FreeBSD kernel could be compared to a termite nest; one initial user leaves a seed of an idea (a mudball) which attracts other users who then build upon and modify this initial concept, eventually constructing an elaborate structure of connected thoughts.

Yes, you could compare Wikipedia to a termite’s nest – but you could also contrast it to a termite’s nest: the basic structure was designed and did happen randomly.  While contributors may suggest unexpected new topics there is an overall governance in place.  All the contributors know what they are doing and are aware of the larger effort of the wiki. It also has a purpose exterior to the efforts of the termites contributors which is the gathering and dissemination of knowledge.  Insofar as a termite’s nest has a purpose it is the survival and propagation of termites.

All of this is obvious to anyone with a mind.  One’s initial conclusion upon reading the above would be that someone heard about stigmergy and just got analogy-happy.

Except for this, also from the same Wikipedia article:

Heather Marsh, associated with the Occupy Movement, Wikileaks, and Anonymous, has proposed a new social system where competition as a driving force would be replaced with a more collaborative society. This proposed society would not use representative democracy but new forms of idea and action based governance and collaborative methods including stigmergy. "With stigmergy, an initial idea is freely given, and the project is driven by the idea, not by a personality or group of personalities. No individual needs permission (competitive) or consensus (cooperative) to propose an idea or initiate a project."

If that quote doesn’t send a shiver of apprehension up your representative democratic spine, I have a nice, busy hive-mind to send you to.  They twitter with excitement for your assimilation.

I have been pondering this idea of stigmergy for a long time and hoping to write an essay or, now, a blogpost, about it.  The problem is that the topic really keeps unfolding into other areas, there are so many pheromone paths to follow – so many, so many -- what am I to do?

I am to cut it off here and keep thinking about the rest of the material I’ve gathered and will gather.  In the meantime, because he really is quite a dog, here is a fuller quote from Roland:

“It’s all about freedom, you see,” he said; “that’s what makes this picture of an interior psychomachy so delectable to late modern persons. It’s a passion for determinism—physiological, subconscious, socioeconomic—what have you. It’s all to do with the final triumph of the mechanistic philosophy in every sphere, even that of consciousness. How silly. As if machines could delight in bacon, or in the chasse sauvage when some impudent rabbit scampers past one’s nose, or in that romp that amuses you so—what’s it called? ‘Fetch?’ Yet nothing so excites the modern materialist as the possibility of proving that consciousness is reducible to physiology, that freedom is an illusion, that mind is a ghostly epiphenomenon of unconscious metabolisms. Every aspiring young materialist dreams of growing up to be a robot.”

Winter of Darwin II

Winter of Darwin II

Voyaging with Beagle…

I realized with a start that germ theory had not yet been developed when Darwin wrote of his voyage on the Beagle.  While in Polynesia he notes a missionary who observed that “most of the diseases which have raged in the islands during my residence there, have been introduced by ships; and what renders this fact remarkable is, that there might be no appearance of disease among the crew of the ship which conveyed this destructive importation.”  (p. 375-376)  Darwin and his contemporaries knew that there was some method of transmission and that some exposed people were affected and some were not.  But they did not know the means of transmission.  Some ideas we learn to take so thoroughly for granted that we assume they must have been known forever. 

On the subject of missionaries, by the way, Darwin was generally approving of the English missionaries in the islands and found their work among the natives to be a positive influence.  Not so the Catholics in South America: "...but he could scarcely have been an Indian, for the race is in this part extinct, owing to the Catholic desire of making at one blow Christians and Slaves." (p. 252)

Through most of his voyage and his book, Darwin registers his disapproval of something with a quick observation and moves on – as with the comment on Catholics above.  But near the end of the book, in Brazil, he launches a spirited, eloquent condemnation of slavery with the sentence, "I thank God, I shall never again visit a slave-country." And he continues for an uncharacteristic two pages, giving examples from his travels of mistreatment observed.  “And these deeds are done and palliated by men, who profess to love their neighbors as themselves, who believe in God, and pray that his Will be done on earth!  It makes one’s blood boil, yet heart tremble, to think that we Englishmen and our American descendants, with their boastful cry of liberty, have been and are so guilty…” (pp. 426-427)

It is a truism now that his visit to the Galapagos Islands spurred Darwin’s thinking along the lines of natural selection.  He was already keenly observant of how geographic barriers affected species population (see p288, for a non-Galapagos example re the Andes Mountains).  Certainly the many species unique to the Galapagos – or even unique to specific islands – made him think.  The islands were over 500 miles west of South America.  In his words, (p329), “…hence, both in space and time, we seem to brought somewhat near to that great fact - that mystery of mysteries - the first appearance of new beings on this Earth.”

On the Origin of Species…

Where the “Voyage of the Beagle” benefits from the narrative framework of a voyage, “Origin” is a scientific thesis.  Still, there are numerous charming details sprinkled throughout whenever Darwin uses his own experience to buttress a point.  Thus we learn that he has long kept and bred pigeons, he has an extensive garden, he floats seeds in fresh and in salt water to see how long they float and if the germinate after, he tracks ants hundreds of yards to their nest, he collects bird droppings to see what seeds survive in them, and on and on.  If he hadn’t published a pivotal scientific work, he would have been thought an eccentric, slightly daft old codger.

Darwin made it a point to include likely objections to his theory of natural selection.  I like the intellectual honesty of this and I was struck by how many of these objections are repeated by modern opponents of evolution – as if newly discovered!  The eye, for example.  How could something so complex as the eye have evolved?  By the gradual accumulation of advantageous variations over countless generations, Darwin posited.

It seems to me that Darwin and his contemporaries did not have a reliable estimate as to the age of the earth.  Darwin refers to countless ages or generations, but he does not name a figure.  I don’t think it was until radioactive dating in the 20^th century that scientists were led back and back to the 4.5 billion year estimate we hear now.

This did leave Darwin and his theory necessarily vague on how long nature would have had opportunity to vary and select among the species.  I’ve always thought it a weakness of evolution to appeal to as many millions of generations as needed to explain a given result.  Lacking a good estimate of the earth’s age, Darwin avoided speculating on specific time boundaries.

And while on the subject of things Darwin didn’t know there is the source of the variation that he made the basis of his theory.  The fact of variation of offspring from parents was widely known and was used by breeders to cultivate favorable traits in domesticated animals, but the source of variation would not be unraveled for decades after Mendel’s 1866 paper.

Everyone feels free to have an opinion of the theory of evolution but what strikes me is how thoroughly steeped in nature studies Darwin was.  How informed, therefore, his conclusions by ceaseless observation.  Somewhere in “Beagle” Darwin writes to the effect that, “it is as difficult not to have an opinion as to have a correct opinion.”   How many of us consciously make that distinction – whether about evolution or anything else?