Last Year in Marienbad
Wesley Elsberry’s Weasel Program
Abstract
© Dr M D Magee
Contents Updated: Tuesday, 31 March 2009
God’s Defenders Keep On Lying!
We read that William Dembski, a well known creepy character from the Discovery Institute who thinks God wants Christians to be liars and cheats is lying and cheating again. Richard Dawkins in his book, The Blind Watchmaker invented a simple algorithm to show how selection makes all the difference to supposed blind and random mutation. Selection is not blind or random. Only some forms survive to breed a new generation, so selection eliminates a lot of inapproriate variations.
Dawkins chose the line from Shakespeare, “METHINKS IT IS LIKE A WEASEL” written entirely in capital letters as the “form” of a string best adapted to the hypothetical string environment supposed by the program. The aim is to find a string randomly that is best adapted to the environment, ie it matches the given string. The fitness criterion is simple that string which is closest to the fittest.
If this were to be achieved by mutations of a single letter in each generation, with no selection process, we have the monkey trying to type Shakespeare scenario, whence Dawkins’ choice of phrase. It would take a very long time indeed because with over fifty characters per letter in a sentence of 28 letters, the possibilities are around 2850, an enormous number. But when the environment eliminates many options, and only what remains, the best adapted or fittest, is allowed to breed, the result is astonishingly quick, given reasonable parameters.
Among God’s liars, Dembski is allegedly a mathematician, but he just cannot bring himself to accept that this procedure works and indeed illustrates, howbeit crudely, evolution. So, Dembski accuses Dawkins of being the cheat, claiming the program fixes the good choices when they have been selected, so that they are no longer subject to the mutation process. It is not so! Of course, once the string gets close to being the best adapted, many mutations will make it less well adapted, and so they will not be selected. It might make it seem as if the selections are fixed, but actually mutations are made but not selected because they make the string less fit.
Should anyone believe Dembski as many dumbski Christian fundamentalists do, Wesley R Elsberry last year wrote a program in JavaScript that lets anyone see clearly online what is happening, and that the accusation of Dembski and his dumbskis is false. Elsberry writes:
The demonstration shows that cumulative selection, premised on natural selection, is far more efficient than random search on the problem posed, that of finding a particular string.
Below is Elsberry’s demonstration, changed only to make it fit this page better, and by choosing the more appropriate statements: “GOD IS DEAD KILLED BY SCIENCE”.
That Dembski is wrong is easily shown by increasing the mutation rate. It is known from nature that large mutation rates spoil evolution because forms mutate too easily to be stable, and a large mutation rate here will show it by demonstrating that already selected forms suitable for the environment can be rendered unsuitable—they are not fixed—and it takes longer to settle upon the best adapted form because less well adapted offspring can generate too easily. In the example copied below, a well adapted [ I] becomes a maladapted [bw] in generation 16, and later another well adapted [ ] becomes a maladapted [x] (pop 500, mutation rate 14). The target was still reached in 65 generations:
Gen. 14, 23 letters, GOD If hEAD KILLED iY ShIENpf
Gen. 15, 23 letters, GOD Iw hEAD KILLED iY ShIENpf
Gen. 16, 23 letters, GODbww DEAD KILLED BY ShIENpf
Gen. 17, 23 letters, GODbww DEAD KILLED BY ShIENpf
Gen. 18, 23 letters, GODbww DEAD KILLED BY ShIENpx
Gen. 19, 24 letters, GODbwz DEAD KILLED BY SCIENpx
Gen. 20, 25 letters, GODbwt DEAD KILLED BY SCIENCx
Gen. 21, 25 letters, GODbwS DEAD KILLEDxBY SCIENCx
Gen. 22, 25 letters, GODbwS DEAD KILLEDxBY SCIENC
Several pages can be found online with the Dawkins weasel program written in different languages by searching “Weasel Program Dawkins”
Elsberry’s String Selection Program
Wesley Elsberry writes that he does not expect his program to be perfect, and he would love to have constructive feedback. The program is here simply for the random theme, and to illustrate selection. Comments and suggestions about the program should be sent to Wesley at the antievolution.org page linked above.
