[-empyre-] self-modification, emergence

[Mitchell Whitelaw <mitchell.whitelaw@canberra.edu.au>]

I'm going to have a go at self-modifying this tangent back in the 
direction of a-life. Self-modification might also be thought of as 
adaptation, learning, innovation... and depending on your view of 
biology and what constitutes a "self" then you might also find it in 
evolution. Lamarckian evolution theorises adaptive self-modification 
which can be passed on to the next generation. While it's been 
overtaken by Darwinian theories, it's not a done deal - there is some 
controversial science that suggests that parts of the immune system can 
pass on acquired traits (Ted Steele, Lamarck's Signature - see for eg 
http://www.abc.net.au/rn/science/ockham/stories/s14075.htm). If you 
stretch the idea of "self" out to a species (or in to a gene) then 
Darwinian evolution is self-modification too.

A-life, and a-life art, involve the pursuit of the emergent moment of 
excess and surprise. Emergence is a knot unto itself, but the ongoing 
emergence that characterises biological life, requires adaptive 
self-modification. Thinking about self-modifying code (or other 
technological systems) quickly runs us into the problem of brittle 
grammars: basically, how likely is it that some random "mutations" 
applied to a bit of c++ code, are going to result in code that is even 
functional, let alone interesting / adaptive? Imagine a robot trying to 
self-modify by picking parts from the shelves of an electronics store. 
The predefined grammars of our technological forms are not an ideal 
substrate for self-modification. Most artificial evolution gets around 
this by creating a grammar of its own. Some grammars are very rich (eg 
Karl Sims' or Steven Rooke's image breeders) and some are more limited 
(eg Latham's virtual sculptures), but all are constructed and involve 
their own constraints.

My favourite example of self-modification and emergence is the work on 
evolved circuit designs by Adrian Thompson of the COGS lab at Sussex 
(http://www.cogs.susx.ac.uk/users/adrianth/ade.html). Basically he used 
a programmable chip (a FGPA, field gate programmable array) to "breed" 
and automatically test thousands of electronic circuits, on a task such 
as distinguishing between two different frequencies at their inputs. 
Many many generations later, circuits were evolved that indeed 
fulfilled the task. But when the evolved circuits were analysed, they 
were found to operate according to no known principles of circuit 
design... for one thing they were tiny and incredibly efficient (using 
only a small portion of the array) but also they used no internal 
clock, and instead seemed to use the dynamics of interlinked feedback 
loops to analyse the input. Best of all, the circuits didn't work so 
well when the same design was transferred to another chip: the evolved 
design made use of the specific physical characteristics of its 
substrate.

Cheers,

Mitchell
http://creative.canberra.edu.au/mitchell