I wonder if you're inadvertently conflating methodological and metaphysical
naturalism here, Chris. "Without purpose" is not much of a synonym for
"caused by natural processes", unless one is in turn convinced that nature
is completely without purpose. I know -you- and many leading evolutionists
are so convinced (indeed, for many this is absolutely critical, it seems),
but I think you will agree that this conviction is neither foundational for
nor implied by science, at least if the history of science is any guide.
This is why the NCTB (is that the right acronym?) modified its statements
recently to avoid this kind of language.
There's no question that purpose does not explicitly inhere in our
forumulations of the laws of physics, chemistry, biology, population
genetics, etc.. That's an important and philosophically interesting point.
But, limiting oneself to science anyway, one shouldn't go beyond that. And
maybe you didn't, but it wasn't clear to me.
Perhaps this is precise enough, if not exactly catchy, language:
(1) There is no intentionality or purposiveness explicit in any hard-science
(2) There is no intentionality or purposiveness underlying any hard-science
Proposition (1) seems pretty unambiguous, at least so long as (hard) science
is methodologically naturalistic and mechanistic. (2) seems more like a
deep philosophical and religious proposition, which science may (I think
must) inform, but does not decide.