Basically looks like a WEASEL, a model of "cumulative selection" which was presented by Richard Dawkins in Chapter 3 of
The Blind Watchmaker.
About 20 years ago, I used his description (he didn't post the code) to write my own WEASEL in Turbo Pascal and called it MONKEY, after Eddington's infinite monkeys (though not based on the Internet's "Infinite Monkey Protocol Suite" (IMPS),
RFC 2795 (01 April 2000)). Musgrave included it in his
Almost Like a Whale page where he includes many other WEASELs as well. He links to a self-extracting archive of my source code and executable, plus another link to a mathematical analysis I had written. Turns out that despite low probabilities for each individual step, the probability that each and every step would fail (a requirement for the whole system to fail) is vastly less, the end result being that the probability of eventually reaching the goal (eventually meaning within minutes or seconds) exceeds 99.99%. In comparison, single-step selection would have to run for several times longer than the current age of the universe in order to have one chance in a million of success.
If you try to run the program, it will crash. That is because your PC is too fast. The Turbo Pascal start-up code has a timing loop that calibrates its delay timeouts. I think it was around the time the first Pentium came out that the processor's speed became too great and as a result that start-up code would crash. Borland did eventually issue a patched start-up module that I linked in, but it didn't make it to Musgrave's site.
I had started to convert MONKEY to C, but its original design was strongly based on the Pascal idiom to make that conversion easy.
- A. S. Eddington. The Nature of the Physical World: The Gifford Lectures, 1927:
... If I let my fingers wander idly over the keys of a typewriter it might happen that
my screed made an intelligible sentence. If an army of monkeys were strumming on
typewriters they might write all the books in the British Museum. The chance of
their doing so is decidedly more favourable than the chance of the molecules
returning to one half of the vessel.
- Douglas Adams. The Hitchhikers' Guide to the Galaxy:
"Ford!" [Arthur] said, "there's an infinite number of monkeys outside who
want to talk to us about this script for Hamlet they've worked out."
- Lennon and McCartney:
Everybody's got something to hide, except for me and my monkey!
- RFC 2795: The Infinite Monkey Protocol Suite (IMPS)
Abstract
This memo describes a protocol suite which supports an infinite
number of monkeys that sit at an infinite number of typewriters in
order to determine when they have either produced the entire works of
William Shakespeare or a good television show. The suite includes
communications and control protocols for monkeys and the
organizations that interact with them.
Edited by dwise1, : Custom Signature
™ Version 4.2
