Russ,
Good questions. I'm hoping Nick will speak up, but I'll hand
wave a little, and get more specific if he does not.
This is one of the
points by which a whole host of conceptual confusions enter the discussion of
evolutionary theory. Often people do not quite know what they are asserting, or
at least they do not know the implications of what they are asserting. The
three most common options are that "the species evolves", "the trait evolves",
or "the genes evolve". A less common, but increasingly popular option is that
"the organism-environment system evolves". Over the course of the 20th century,
people increasingly thought it was "the genes", with Williams solidifying the
notion in the 50s and 60s, and Dawkins taking it to its logical extreme in The
Selfish Gene. Dawkins (now the face of overly-abrasive-atheism) gives you great
quotes like "An chicken is just an egg's way of making more eggs." Alas, this
introduces all sorts of devious problems.
I would argue that it makes
more sense to say that species evolve. If you don't like that, you are best
going with the multi-level selection people and saying that the systems evolve.
The latter is certainly accurate, but thinking in that way makes it hard to say
somethings you'd think a theory of evolution would let you say.
Eric
On Mon, May 9, 2011 06:25 PM,
Russ Abbott
<[hidden email]> wrote:
I'm
hoping you will help me think through this apparently simple
question.
When we use the term evolution, we have something in mind
that we all seem to understand. But I'd like to ask this question: what is it
that evolves?
We generally mean more by evolution than just that change
occurs--although that is one of the looser meaning of the term. We normally
think in terms of a thing, perhaps abstract, e.g,. a species, that evolves. Of
course that's not quite right since evolution also involves
the creation of new species. Besides, the very notion of species
is <a href="http://plato.stanford.edu/entries/species/"
onclick="window.open('http://plato.stanford.edu/entries/species/');return
false;">controversial. (But that's a different discussion.)
Is it appropriate to say that there is generally a thing, an
entity, that evolves? The question is not just limited to biological evolution.
I'm willing to consider broader answers. But in any context, is it reasonable
to expect that the sentence "X evolves" will generally have a reasonably
clear referent for its subject?
An alternative is to say that what we mean by "X evolves" is
really "evolution occurs." Does that help? It's not clear to me that it
does since the question then becomes what do we means by "evolution occurs"
other than that change happens. Evolution is (intuitively) a specific kind of
change. But can we characterize it more clearly?
I'm
copying Nick and Eric explicitly because I'm especially interested in what
biologists have to say about this.
Eric Charles
Professional Student
and
Assistant Professor of Psychology
Penn State University
Altoona,
PA 16601
Meets Fridays 9a-11:30 at cafe at St. John's College