Meet the Strandbeests - Evolution News & Views

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Meet the Strandbeests

Dutch inventor, artist, and engineer Theo Jansen has spent the last twenty years working on what he has deemed to be artificial life. His artificial life is a kind of contraption called a Strandbeest (Strand = beach; beest = beast). You'll find more videos on his website. He describes the strandbeests as though they were truly animals that he invented. Some models that did not work he speaks of as having gone "extinct," and places them in a "boneyard" where they may "fossilize." When he is making adjustments to working models, he calls this "training" them. He characterizes the beach as their "natural habitat." His goal is to make the strandbeests truly self-sustaining, so that he can eventually allow them to "live" freely on the beach.

These strandbeests are made of lightweight recycled yellow tubing of a sort that is used in construction. Despite Mr. Jansen's apparent eccentricities, seasoned with something of a Frankenstein complex, his engineering design is actually quite brilliant. His contraptions are propelled by wind as their energy source. The strandbeests have a "stomach" (as he calls it) that consists of bottles and bicycle pumps, which receive wind that has been harnessed by the "wings." This wind energy is stored as potential energy. When the bottles are filled, the wind is released, providing the energy to propel the contraptions.

A key feature of Mr. Jansen's model is the way he simulated muscles to allow for movement. The leg of the strandbeests is complicated. It is constructed of eleven small rods, and in order to produce a structure that will walk on its own, propelled by wind, the rod lengths needed to be in a particular ratio. That ratio will provide the appropriate curvature for walking:

But even for the computer the number of possible ratios between 11 rods was immense. Suppose every rod can have 10 different lengths, then there are 10,000,000,000,000 possible curves. If the computer were to go through all these possibilities systematically, it would be kept busy for 100,000 years. I didn't have this much time, which is why I opted for the evolutionary method.
He calls this ratio the eleven holy numbers. He describes his "evolutionary" model as follows:
Fifteen hundred legs with rods of random length were generated in the computer. It then assessed which of these approached the ideal walking curve. Out of the 1500, the computer selected the best 100. These were awarded the privilege of reproduction. Their rods were copied and combined into 1500 new legs. These 1500 new legs exhibited similarities with their parent legs and once again were assessed on their resemblance to the ideal curve. This process went through many generations during which the computer was on for weeks, months even, day and night. It finally resulted in eleven numbers denoting the ideal lengths of the required rods. The ultimate outcome of all this was the leg of Animaris Currens Vulgaris. This was the first beach animal to walk. And yet now and then Vulgaris was dead set against the idea of walking. A new computer evolution produced the legs of the generations that followed.

These, then, are the holy numbers: a = 38, b = 41.5, c = 39.3, d = 40.1, e = 55.8, f = 39.4, g = 36.7, h = 65.7, i = 49, j = 50, k = 61.9, l=7.8, m=15 . It is thanks to these numbers that the animals walk the way they do. [emphasis added]

This was a brilliant idea, but that is why you could not accurately call it, as Jansen does, an evolutionary model. Evolutionary models are not brilliant, they are random. Mr. Jansen knew what he was looking for. He had the ideal in mind and was looking for the closest approximation of his ideal. At work here is something more akin to a Platonic form than to an evolutionary model. The strandbeests are works of engineering, not the product of random, naturalistic processes. Jansen's computer simulation does use a type of trial-and-error system where it seems to learn from the last trial to then attempt another iteration of ratios that would ultimately provide a leg structure that is closest to the ideal. However, there is always an ideal in mind.

Another way of thinking about it is Jansen knew what he wanted the parts to do; he just needed the right combination of parts to do it. Evolution does not "know" beforehand what it wants the organism to do. That would require foreknowledge and purpose, and evolutionary theory is distinctly purposeless.

There are two further things we can learn from Jansen's work:

While the strandbeests probably fall under the category of art or engineering rather than artificial life, they are a good example of the engineering parameters required to do something as commonplace as walking. Such things are studied in the field of biomechanics, where one may indeed view living organisms as works of engineering. Biomechanics, in general, is a great example of a field that benefits from seeing living things from a design perspective.

Secondly, we can learn something about the term "evolution," used in so many different ways, and about computer simulations of "evolutionary" processes. Evolution can be defined as adaptation to an environment. It can be defined technically as natural selection acting on random mutations. Some people use the word to describe an ideological viewpoint that is better described as Darwinism. Darwinism refers to the evolutionary processes we actually do observe and the ideology, popularized by Charles Darwin, which co-opts those observations into a larger origins story. And then there is the loose catchall definition of evolution as "change."

Computer simulations like this do not illustrate evolution in any sense because the ideal was already in mind -- it never changed -- and a mind in control of things is anathema to Darwinian evolutionary theory. It is biomechanics, engineering, mathematics, and even art that we in Jansen's work, but there is no naturalistic evolutionary process going on here.