Sunday, October 21, 2007

I can’t believe Dembski chose Word Mutagenation!!

Take a look at William Dembski’s latest draft manuscript, Active Information in Evolutionary Search The Information Cost of No Free Lunch.

Dembski: Proponents of intelligent design have argued that the NFLT shows that Darwinian evolution cannot generate the information required for biological complexity from scratch but instead merely reshuffles existing information.

The NFLT (No Free Lunch Theorem, Wolpert and Macready 1997) doesn’t suggest that Darwinian Evolution can't generate information in the sense of searching a fitness landscape. Rather, it merely states that it may or may not be the best conceivable algorithm for finding fitness.

Dembski: Making such assumptions about underlying search structures is not only common but also vital to the success of optimizing searchers (...).

Such assumptions, however, are useless when searching to find a sequence of, say, 7 letters from a 26-letter alphabet to form a word that will pass successfully through a spell checker… With no metric to determine nearness, the search landscape for such searches is binary—either success or failure. There are no sloped hills to climb.

I can’t believe Dembski chose Word Mutagenation!! He couldn't be more wrong.

It’s been three years since I published Word Mutagenation on the web, the result of a year-long thread on the newsgroup Talk Origins with Intelligent Design advocate, Sean Pitman. I suppose it’s time to dust off the old Letter Mutator and take another look.

Turns out we don’t have to make any assumptions about the search space of words. For instance, we could start with the single-letter word “O”, a replicating population representing a veritable Pond of O’s flowing down to the Sea of Beneficence.

In the beginning was the Word.

We then mutate words in our Sea. We might change a random letter, add a random letter, delete a random letter, or randomly recombine words in the Sea. Something like this:



If a mutant sequence is not a valid word, that is, if it fails the spell-checker rule that Dembski established above, then it is ruthlessly eliminated with no issue. If it is a valid word, it enters the population as a new strain. (We might optionally limit our Pond of Words to just a certain number of the longest words.) So, what do we expect?

Quick calculation:
10-letter words in dictionary ~10^4
10-letter sequences possible ~10^14
Ratio of valid 10-letter words to possible sequences ~10^10

A random search would take ~10^10 or several billion mutations. An evolutionary search algorithm takes only ~10^5 mutations or about a hundred thousand times faster—consistently. There is nothing about the structure of words in Word Mutagenation. It works in the simplest of fashions; random mutation and spell-check, over and over again.

The structure is found in the words themselves. Turns out that language itself has evolved and evidence of that history is found in the words we use.

The fault, dear Brutus, is not in our stars,
But in ourselves.

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At 11/01/2007 9:37 PM , Blogger James F. McGrath said...

A blog that ranges from Dembski to Debussy! I will have to add you to my blogroll! :)

At 11/09/2007 12:21 PM , Anonymous Sean Pitman said...

Hey Zach . . .

I see you are still confused about the actual mechanism of random mutation and function-based selection. Again, your problem is that your computer "phrasenator" doesn't judge "beneficially meaningful" sequences when it comes to selectability. It also doesn't give different weights or odds to different types of mutations (i.e., single vs. multicharacter).

As I've pointed out to you before, your computer simulations just don't simulate random mutation plus function-based selection. Sorry, but that's the truth.

Sean Pitman

At 11/09/2007 5:55 PM , Blogger Zachriel said...

Hi Sean, I hope you have been well.

Sean Pitman: "I see you are still confused about the actual mechanism of random mutation and function-based selection."

The subject of this particular thread is Dembski's specific claim that the word-landscape can't be searched by a standard evolutionary algorithm, but must include assumptions about the nature of the landscape. In fact, the evolutionary algorithm of Word Mutagenation is very generalized and includes no specific information about the landscape under question.

Sean Pitman: "Again, your problem is that your computer "phrasenator" doesn't judge "beneficially meaningful" sequences when it comes to selectability."

Dembski provided a very specific test for fitness, a spell-checker.

Sean Pitman: "It also doesn't give different weights or odds to different types of mutations (i.e., single vs. multicharacter)."

It does. In addition, the open source code is easily modified.

At 12/19/2007 4:37 PM , Anonymous Hector Caballo said...


How much does this program corelate to Dawkins Weasel Program, made back in 1996?


Hector Caballo

At 12/19/2007 5:01 PM , Blogger Zachriel said...

Hi Hector,

Only a bit. Dawkins was showing a much more limited situation. His program assumes there is some function if it matches the prespecified target at any letter position.

Word Mutagenation has no preset goal, each member of the population must form a complete word, and each history will probably be substantially different.

At 12/19/2007 5:55 PM , Anonymous Hector Caballo said...


That's actually a better program then, as Evolution has no Telos, a concept that could be applied to the phrase Dawkins specified.

But it is a nice show on how Evolution works without dealing with improbable situations. Most Creationists ignore the fact of cumulative selection, as shown by the Weasel program, and twist thing s enough to turn genetic mutation into something purely by chance. A few Creationists I've met defend this, and use analogies to the Infinite Monkey Theorem, etc... But in fact, it is little more than a distortion of facts made to confuse public perception of the darwinian theory of natural selection.

That, and their unsubstiated claims on the lack of beneficial mutations, contradicting directly what was observed in nature with the HIV virus, and a bacteria that turned capable of digesting Nylon:


H. Caballo

At 3/02/2008 9:49 AM , Blogger Zachriel said...

Apparently, the old link to Dembski's paper no longer works. The paper has a new title. I updated it above.

At 3/02/2008 9:56 AM , Blogger Zachriel said...

Apparently, CJYman disagrees with this post. You can read our discussion on his blog, Reality Cheque.

At 4/14/2008 9:40 AM , Blogger Doppelganger said...

I noticed that the 'Reality Cheque' blogroll contains Joe Gallien's blog.

For me, 'nuff said.

At 6/15/2010 5:19 AM , Blogger 小晶 said...

IS VERY GOOD..............................


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