Cumulative vs Single-step natural selection: aka the Shakespearean Monkey
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16-06-2011, 06:26 PM
Cumulative vs Single-step natural selection: aka the Shakespearean Monkey
This is more or less an excerpt from Dawkin's book The Blind Watchmaker, but I swear I've seen the Shakespeare/Monkey discussion on here before and it was misrepresented and erroneous.

The saying is: "Given enough time, a monkey bashing away at random on a typewriter could produce all the works of Shakespeare."

This is used as a example of how something that seems designed could come about through chance given a long enough timeline. But the error occurs when the theist tries to conceive of that scenario using "single-step natural selection." Let's use an example of the two natural selections using the sentence from Dawkin's book:

METHINKS IT IS LIKE A WEASEL


I don't know why he chose that (British people...) but anyways, there are 28 characters in this sentence. The problem with "single-step" is that the monkey types 28 characters, and then tries again, and again, each time typing 28 new characters until the sentence happens to be the one above. Doing the math, each character has a 1/27 chance (every letter including the space bar as a character) of hitting the right letter. So for a 28 character sentence, you would have a (1/27)^28 chance or a one in a 10,000 million million million million million million chance that the monkey will get all the letters correct at the same time.

Whereas a cumulative natural selection keeps "correct" letters with each new try. For instance, maybe on the first attempt, the monkey types:

MCXZER GFDDELKKQWTBBSAASZ TK

Cumulative natural selection would keep the advantageous letters (the first M in this case) for the next attempt, aka generation.


(From the book)
"Not an obvious improvement! But the procedure is repeated, again mutant 'progeny' are 'bred from' the phrase, and a new 'winner' is chosen. This goes on, generation after generation. After 10 generations, the phrase chosen for 'breeding' was:

MDLDMNLS ITJISWHRZREZ MECS P

After 20 generations it was:

MELDINLS IT ISWPRKE Z WECSEL

By now, the eye of faith fancies that it can see a resemblance to the target phrase. By 30 generations there can be no doubt:

METHINGS IT ISWLIKE B WECSEL

Generation 40 takes us to within one letter of the target:

METHINKS IT IS LIKE I WEASEL

And the target was finally reached in generation 43."



A subsequent repeat of the above reached the sentence in 41 generations of selective breeding.

Human evolution is, of course, cumulative. When we give birth to offspring, we don't get a random variation of genes. Two 5 foot asians have never given birth to a 7 foot black man with red hair and "motion sensors" instead of eyes. It's not a random roll of the dice of all things possible, it's a collection of the genes that allowed the two asians to survive up to that point.

And instead of a "target phrase" to "work towards," human evolution simply follows the rule: "If you survive long enough to breed, then the genes of a survivalist will be combined with genes of someone who also survived, creating a being who is now made up of genes that are advantageous for human survival."

...once I find a way to shorten it, I'm making a bumper sticker out of it.

"Ain't got no last words to say, yellow streak right up my spine. The gun in my mouth was real and the taste blew my mind."

"We see you cry. We turn your head. Then we slap your face. We see you try. We see you fail. Some things never change."
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16-06-2011, 11:49 PM
RE: Cumulative vs Single-step natural selection: aka the Shakespearean Monkey
Just have a bumper sticker with an Asian couple discussing their son is Godzilla =p (note in general i tire of these sorts of jokes but the motion sensors instead of eyes made me think of it). The caption should be I thought this was "intelligent" design.

I'm not a non believer, I believe in the possibility of anything. I just don't let the actuality of something be determined by a 3rd party.
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