Re: No drive for drift... was Re: Tears and 'salt excretion'

H. M. Hubey (
6 Nov 1995 22:22:03 -0500 (Bill Burnett) writes:

>Oops, I've used the d-word. No, actually, I don't object to the d-word in
>this sense, I object to the d-word in the H. sapiens is the be all and end all

You've made my day :-).. As long as we can discuss the D-words
then we've made progress.

>top of the heap closest to God sense. I object to a 'universal' direction as
>a driving force for evolution, at the head of which stands Hubey.

Well, I can't put much meaning into the word "universal" here. As for
force, or driving force, those are powerful words indeed :-)..

In fact,that's exactly what is implied. For example the existing
genetic population models (Wright, Kimura etc-- see Roughgarden or
Kojima) deal only with PDE's (diffusive ones, say, for the probability
density of a gene frequency) {PS. See my other post on the
Bell Curve. That paper has a more detailed explanation}. These
PDE's can be derived also from DE's with the addition of noise
or via making the coefficients random. That means that if we have
a DE like this

x' = f(x) + g(x)w(t)

where w(t) is noise then there really is a "driving force".
In this case it's just noise. If we wanted to include the
effects of the environment we'd have something like

x' = f(x) + g(x)w(t) + q(t)

where q(t) would be exactly the driving force that you need.

>Owen, or Adam. Evolution needs no direction but proceeds in many different
>ones regardless. I don't say it just does, I've offered mechanisms by which
>it works. I fail to see how any direction can be considered any better than
>any other direction.

I didn't intend to argue about meanings of words. But practically
by any measure of overall complexity we are more complex.
We cannot say that a bicycle is more complex than a car because
it doesn't have an engine that can break down. That's not complexity;
that's simplicity. That's an engineering maxim called the
KISS principle: Keep It Simple, Stupid.

>No, actually, the authors admit to stealing the diffusion approximation.
>That's precisely why it's called the diffusion approximation in stead of
>something more imaginative.

Whatever works works. In that case, I'll be happy to take credit for
it. On the next draft of the paper, I'll add more.

>The problem is you think more complex in terms of brain power = higher.
>Some people might not have a problem with that. I do. I suggest we drop it.

We can drop it. But before we do that let's consider a number
from Churchland (the Searlian nemesis). The number of brain
states of a human being (possible on-off states of all neurons)
is 10^(10^8) or 10^10000000. By comparison, the total number
of elementary particles in the universe (including photons)
is 10^87. Now that's complexity.


Regards, Mark