The battle over cumulative selection and Dawkins’ Weasel program has raged on for some months [years?] here at TSZ and across numerous threads. So can it possibly be that we now, finally, have a definitive statement about cumulative selection?
Mung: And whether or not my program demonstrates the power of cumulative selection has not been settled…
To which keiths responded:
keiths: Anyone who understands cumulative selection can see that it doesn’t, because your fitness functions don’t reward proximity to the target — only an exact match. The fitness landscapes are flat except for a spike at the site of the target.
So there you have it. You need a target and a fitness function that rewards proximity to the target.
Imagine my surprise when I discovered that I had said the exact same thing nine months ago.
Mung: Here’s what he Weasel program teaches us:
1.) In order to demonstrate the power of cumulative selection one must first define a target.
2.) In order to demonstrate the power of cumulative selection one must define a fitness function that increases the likelihood of the search algorithm to find the target relative to the likelihood of a blind search finding the target.
Now perhaps I have misunderstood keiths here. Perhaps he did not really say, or really mean, what I think he said, or what it appears like he said. So I’d like to hear his response.
Is it possible that keiths has agreed with me all along while expending every effort possible to make it seem otherwise?
Just so there’s no mistake, here he is again saying the same thing:
Besides failing in your attempt to code a Weasel and contradicting yourself regarding your intent, you also failed to demonstrate the power of cumulative selection in your program.
1) Your program doesn’t evolve a phrase; it evolves individual letters, one after the other, latching each one when it matches.
2) There is a separate fitness function for each letter.
3) The fitness functions don’t reward proximity to the target — they only reward an exact match for a single character.
The only thing your program demonstrates the “power” of is latching, not cumulative selection.
It’s a remarkable display of incompetence.
Perhaps. But it served its’ purpose. keiths admits I was right all along. So incompetence? Perhaps not.
You need a target. You need a fitness function that rewards proximity to the target. Is that your story keiths, and are you sticking to it? Weasel out of this!
I predict keiths will try to make this about my program and what it does or does not demonstrate rather than his revelation about cumulative selection.