Genetic algorithms are in the news again. This news comes at a fortunate time, as we’ve been discussing creationist criticisms of the breakthrough by Craig Venter, who recently announced that his lab has created a bacterial cell with a synthetic genome.
Venter’s accomplishment is being derided by creationists of every stripe. Some even claim that his work supports their own nonsense. That argument asserts that because Venter’s team required some intelligence to create a bacterium with an artificial genome, nature must have required intelligence when creating original bacteria. An example of this argument is here.
It’s true that copying something found in nature requires conscious effort on our part; but that doesn’t support the creationists’ claim that nature required any intelligence or even consciousness to get the results we try to copy. Genetic algorithms are excellent evidence of nature’s ability to produce spectacular results without thought.
We’ve written before (here, and then here) about the increasing use of genetic algorithms to solve engineering problems. There are numerous applications. Here are more specific examples of genetic algorithms being used to solve a variety of problems. And the work goes on.
Today, in New Scientist, we read Darwinian spacecraft engine to last twice as long. Here are some excerpts, with bold added by us:
SPACE agencies may one day have Charles Darwin to thank for the longevity of their spacecraft. The life expectancy of a popular type of ion engine has been almost doubled using software that mimics the way natural selection evolves ever fitter designs.
Interested? Sure you are. Let’s skip a few technical details and then read on:
… [S]ome ions collide with the grid itself, causing it to gradually wear out, says Cody Farnell, a space flight engineer at the University of Colorado in Fort Collins. Simulations suggest grids in a typical NASA engine will last 2.8 years — but Farnell wondered whether changing the grid’s design could extend its lifespan.
That’s the problem — the grid wears out quickly. To learn about the solution, let’s continue:
He used evolution-mimicking software called a genetic algorithm (GA), and started by instructing the algorithm to randomly generate values corresponding to the geometry of the grid and the voltages applied to it. These values can be thought of as analogous to genes.
Well, what happened? Did evolution improve the grid? Here’s more:
After 100 generations, the GA spawned a geometry/voltage set that boosted the ion engine grid’s lifetime to 5.1 years — at least in the simulator (Journal of Propulsion and Power, DOI: 10.2514/1.44358). Factors optimised included grid hole diameter, hole spacing and the thickness of the grids. The engine could be improved further, says Farnell, by evolving the other parts too.
Here’s a link to Farnell’s article: Ion Thruster Grid Design Using an Evolutionary Algorithm, but you’ll need a subscription to read it.
So, class, what do we learn from this? We learn that the creationists are flat-out wrong when they assert — as they always do — that the so-called biological wonders of creation had to be deliberately devised by a wise and benevolent designer. The everyday use of genetic algorithms to solve difficult design problems clearly demonstrates, again and again, that the unthinking processes (mutation and natural selection) identified by Darwin are quite sufficient for the task.
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