Complexity

Complexity, Emergent Behavior and Christmas Tree Lights

By Chris Gulker

For the better part of 50 years, a certain Redwood tree in Silicon Valley has been lit during the holidays, decorated with strings of multi-colored lights.

It stands a short block off Sand Hill Road, Silicon Valleyís Wall Street. 1 2years ago I bought the house upon whose lot the Redwood stands, from a retiring engineer, becoming the keeper of this icon.

Which is why Iím balanced on a ladder in a thunderstorm, wires and flashlight in one hand, a fuse in the other, trying to find out why my holiday lights keep blowing out. The rain, the wind, the threat of imminent electrocution, somehow canít keep me from thinking about the topic of emergence.

This should be easy: there are some 10 strings of 25 lights. Each light is a simple deal: a 7-watt bulb hanging off a pair of wires, hooked to a timer via a state-of-the-art, ground-fault protected, 60-amp circuit.

As simple as the system is, a really weird thing happens: I turn the lights on; within an hour or two, the lights blow. I replace the fuse, the sequence repeats. Weíve been through a whole box of fuses.

My wife is annoyed. Iím stumped: 7 watt bulbs, 60 amp circuit. Has worked without fault for 12 years. Why?

Emergent behavior may be what Iím up against here: simple systems, with simple rules often demonstrate behavior that is quite complex. Each bulb is a very simple system, obeying, among other things, Ohmís law. Yet the 250 or so bulbs in my system suddenly display a vexing behavior after 50 years.

Steven Johnson, the editor of Feed, has written a book called, appropriately enough, Emergence, where he tracks the phenomenon in the architecture of cities, the behavior of ants, and of course, in computer systems.

Turns out that highly organized ant colonies are effectively leaderless: each ant has a small number of behaviors ñ forage, remove garbage, fight etc. ñ driven by scents, pheromones that other ants emit. An ant colony, when confined to a limited space, can solve a problem, like keeping the garbage, the ant cemetery and the nest as far apart as is mathematically possible, with great precision.

Simple computer animations, based on a grid of squares that each turn light or dark depending on simple rules about what their neighbors are doing, can display quite sophisticated behavior. A rule might be ìturn dark if no more than 3 neighbors are darkî. Resultant behavior might closely mimic the way bacteria grow, or how a wild animal population behaves. Simple rules breed surprisingly sophisticated behaviors.

Indeed, particle physicists have theorized that all that is, is the way it is, because of the rules obeyed by the most basic particles. Mind you, those rules are weird: even Einstein called them ëspookyí. It can nevertheless be shown that the whole universe would be different, possibly very, very different, if those rules were to change even a little.

So, why do we care? For one thing, emergence might give us a strategy for dealing with a world whose complexity is rapidly outstripping our capacity to deal with it. Good cities might emerge by enforcing rules that make sidewalks pleasant and friendly, rather than from master zoning plans that take decades to develop.

And computer operating systems and software, so clearly beyond their creatorís ability to manage judging by the number of virus-laden emails in my inbox, might improve. Future software might be coded as small pieces that compete to see which gets the job done most reliably.

And my holiday lights, if they canít stay lit, might change their own fuse.