From: Iain Strachan (email@example.com)
Date: Thu May 08 2003 - 16:23:25 EDT
Michael Roberts wrote, in part:
> This seems to me to give no more than Dawkins' computer models in the
It seems we have a rare point of agreement here. In the "Discussion"
section, I read the following:
------------------------ begin quote -------------------
Some readers might suggest that we 'stacked the deck' by studying the
evolution of a complex feature that could be built on simpler functions that
were also useful. However, that is precisely what evolutionary theory
requires, and indeed, our experiments showed that the complex feature never
evolved when simpler functions were not rewarded.
------------------------ end quote ---------------------
In other words, you have to stack the deck because Evolution won't work
unless the deck is stacked. But this is a circular argument and it proves
nothing about whether in fact the deck is stacked in this way in nature; all
they have done is make a simulation that takes that prior assumption for
Examination of the paper shows that they attributed higher degrees of
fitness to organisms that could perform more complex logic operations, with
the "reward" being 2^n where n was the number of logic operations combined.
The EQU function required 5 operations, so was rewarded with 32 points; but
intermediate rewards of 2,4,8,& 16 were also allowed for simple functions.
The fact that the complex feature could not evolve if the simpler functions
were not rewarded is a tacit admission that irreducibly complex systems
cannot evolve. With the intermediate rewards, the system is _not_
irreducibly complex. Knock out one of the 5 logic operations and there are
still 4 left, with a "reward" of 16 points, which is better than nothing and
gives the organism "energy" in order to reproduce. However, if you knock
out any of the components of Behe's mousetrap, then you have a
The debate hinges around whether there really are such things as irreducibly
complex objects in nature & that is still open to question, one which is not
addressed by the simulation of the evolution of a non-irreducably complex
In short, the simulation shows that a GA can do hill-climbing, provided the
gradients aren't too precipitous, but we knew that from the "Weasel"
simulation ages ago.
This archive was generated by hypermail 2.1.4 : Thu May 08 2003 - 16:24:07 EDT