Comments on: Dembski and Marks Are Still Mischaracterizing Dawkins’ “Weasel”

By: Austringer

Austringer — Mon, 23 Mar 2009 03:35:00 +0000

I corrected an antievolutionst on “locking” recently. The issue is what mechanism applies. IDC advocates would like people to think that “locking” is the only way to achieve an increase in performance over random search, since that essentially requires fore-knowledge and would make “weasel” a point in their favor. But the actual mechanism used in “weasel” doesn’t lock and doesn’t require fore-knowledge.

“Latching” would require an internal mechanism with knowledge of “correct” states and the ability to protect “correct” states from mutational processes. That would be counter to what we know of biology, and, indeed, Dawkins himself thought that ascribing “latching” would be didactically wrong.

But if there is no protection of “correct” states, how in the world can there be a mechanism that will accumulate adaptive information over time where all individual traits are treated just the same? Especially when mutating from an adaptive to a maladaptive character is so much more probable than mutating an adaptive character to a maladaptive one. That is what the “weasel” program by Dawkins demonstrates, that given the use of cumulative selection, it becomes likely that an evolving population can be in a situation where adaptive information is retained. It does so in a way that promotes an understanding of why biological evolution happens in reasonable-sized populations with a small but appreciable rate of mutation of inherited information.

Yes, adaptive information is retained in populations meeting those two biologically-relevant criteria (reasonable population size and non-zero small mutation rate), but it is precisely the point at issue that “latching” is not done in order to achieve that. We have no evidence of a generic “latching” capability in biology, but we do have plenty of evidence concerning biological population sizes and mutation rates. So no one is ignoring the fact that “weasel” works; it is precisely to the point that argument ensues when certain people persistently misrepresent the mechanism by which it works. I wonder why they ignore that fact?

By: Steve Taylor

Steve Taylor — Sun, 22 Mar 2009 11:24:53 +0000

Doesn’t some sort of locking exist in the reality of natural selection ? Since a “good” mutation might benefit the organism disproportionately, any mutation of that element would potentially lead to a lower fitness, so the mutation would tend to stay fixed anyway ?

Steve

By: Patrick May

Patrick May — Tue, 11 Nov 2008 19:02:07 +0000

Cool, two examples demonstrating that “cumulative selection” doesn’t entail explicit locking of correct characters.

I’ve run my GA engine under both SBCL and Clozure CL (formerly OpenMCL). It doesn’t use threading (yet) and doesn’t have a GUI, so it should run under any standard Common Lisp.

By: Austringer

Austringer — Tue, 11 Nov 2008 17:49:31 +0000

I have another post up here discussing an implementation of mine. You can see the implementation itself here. Which Lisp implementations should your code work with?

By: Patrick May

Patrick May — Tue, 11 Nov 2008 17:06:18 +0000

I found this page while looking for other implementations of Dawkins’ Weasel. I’d seen a few creationist misrepresentations, so decided to implement a tougher version. It’s available here:

http://www.spe.com/pjm/weasel.html

My implementation uses a stochastic selection mechanism and subjects all bits in the genome to mutation. It also operates on a far larger search space. Unsurprisingly, unless you’re a creationist, differential reproduction operating on random mutation still converges to a solution rapidly.

I think I’ll make some modifications to ev next.

By: RBH

RBH — Sun, 19 Oct 2008 22:02:30 +0000

I went through those pages this afternoon too, and like you found nothing at all having to do with avida or ev. Just the same old misconception of the WEASEL program you identified. Dembski reminds me more and more of Sal Cordova.