Re: Direction in evolution, from Re: Are there things that don't evolve?

Irreducible complexity seems to assume purpose and directionality. To say that a mousetrap will not function if any of its parts are removed assumes that its purpose was catching mice. It will still "function" perfectly well as a paper weight. And again, to say that the constituent parts are useless by themselves assumes that their purpose is catching mice. If the environment doesn't require catching mice, then springs, levers, boards and whatnot could be selected for other uses (uses can be mistakenly interpretted as purpose). Random recombinations of the parts would result in countless structures that appear useless. But when the environment changes to one that favors mice catching, the one that catches mice is selected. Talk about carying an analogy to a ridiculous extreme!
Brent

---- David Campbell wrote:

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There's a lot of confusion regarding directionality and randomness versus
organization in evolution, not merely relating to antievolutionary arguments
but even within evolutionary biology involving folks as well-known as Steve
Gould. It may help to distinguish between the question "Are there
directions in evolution?" and "Can these be called progress?"

First, what is random? It can be used mathematically (things describable
probabilistically, such as flipping a coin) or less formally to include
things that do not fit that mathematical description but that cannot be
humanly predicted in detail (e.g., long-term weather). However, it is also
used metaphysically to mean unguided or purposeless. Many people have tried
to claim that scientific evidence of one of the first two implies the third,
whether they wish to reject purpose or to reject the science. However, most
religions and even superstitions hold that supernatural influences affect or
control items in the first two categories. I'm using it hereafter as a
physical descriptor for things humanly unpredictable while acknowledging
that God is sovereign over what happens.

Human perception of randomness is inaccurate. Random things are actually
less simple than organized things. For example, it is very easy to make a
short description of the following numeric sequence:
0101010101010101010101010101010101010101010101010101010101010101

can be described as "repeat 01 over and over"
However, the following sequence is most easily described by quoting it:
78457841656128561765432657643721654578431587438156842613587436

Thus, in evolution, it would be very orderly to have the planet entirely
populated by clones of a single type of organism. In fact, there is much
more variation in the DNA and in the organisms-much more random. The
construction of an organism from raw materials does impose a certain order,
but it uses energy to do so, and this energy is no longer as available for
useful work, so thermodynamics is upheld.

Also, the organization within organisms is determined by "Whatever works in
the environment.", aka natural selection. This is a strongly non-random
factor affecting evolution, but the environment may be largely determined by
random factors and ordinary actions of natural law. For example, imagine a
computer program that randomly generated mazes and another that used random
processes to solve the mazes. The results of the second program are tightly
constrained by the first, but the overall system relies on mathematical
randomness.
Something else that can make randomness look non-random is the interaction
of random variation with a constraint. A studied example of this comes from
muricid snails. Many today are big and spiny and popular with collectors.
The oldest known ones are small and smooth. Has the group evolved
directionally? Not necessarily, just on this information. There are also
small and/or smooth ones today. You can't have fewer than zero spines, so
random variation starting from one extreme of small and smooth would
gradually fill a range of size and spininess. The average size and
spininess would grow over time and then level off as the range of
possibiities became exhausted. During some periods of time, this is what we
see happening. However, at other points (in time and space), there are
distinct increases in average size and /or spininess, probably reflecting
predation as an agent of natural selection.

Another problem is exactly how one quantifies the degree of complexity or
variability in organisms. The particular example involving Gould I have in
mind comes from the question of comparing the Cambrian radiation with later
diversity. If we look at arthropods, today there are butterflies, worm-like
or sac-like parasites, barnacles, lobsters, fleas, crabs, centipedes,
spiders, etc. That's a lot of variation in form. However, all living forms
fit into just four basic groups according to the number, type, and
sequence of appendages (antennae, mouthparts, legs, etc.) and major
divisions of the body; a fifth category died out with the end-Permian
extinction. In the Cambrian, there are a number of more or less shrimp-like
things that don't fit into any of the five post-Cambrian groups, not to
mention some things that are not quite true arthropods but rather are
transitions between modern phyla. Similar issues arise for other animals.
Which shows greater diversity? Depends on how you measure it.

Nevertheless, there are several well-supported trends in evolution. The
next problem comes in trying to equate such trends with progress. All
purportedly evolution-based moral or social systems make such a claim.
However, as Prince Caspian pointed out, we must distinguish between Progress
and Going Bad. Likewise, Bob Thaves, in a Frank and Ernest cartoon, noted
the compatibility of evolution and the Peter Principle (things progress
until they reach a position beyond their capabilities and are then stuck in
a position of incompetence. It was based on observations of promotion in
business, government, academia, etc.). Equating evolution with progress or
thinking that organisms are in some way trying to evolve in a particular
direction is what is rejected in modern definitions of evolution as
ateleological, without goals. Think of another area of science. Gravity
does not have goals. Something on the floor is not more advanced than
something on a shelf. Even much scientific literature still makes such
claims about evolution, and it is fundamental to Marxism, evolution-invoking
eugenics, etc. The silliness of invoking evolution as progress, however,
can quickly be seen by considering multiple evolutionary trends. Numerous
vertebrates have reduced the number of digits for stronger feet and faster
running. Thus, we can make evolutionary progress by cutting off most of our
fingers and toes. Many parasites or sessile animals have evolved by
reducing the nervous system and muscles; parasites often simplify the
digestive system as well. This also is why "if evolution is true, why are
there still monkeys" is wrong.

Even if one equates evolution with progress as a philosophical assumption,
it still remains necessary to justify which direction is claimed to be more
advanced. In practice, "more like me" is defined as advancement. However,
if someone not too much like me makes such a claim, it is not in my
evolutionary advantage to support it. I might, however, gain evolutionary
advantage by fooling some people into thinking that more like me is better.

--
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"