Interesting essay. Let me explore a couple of points.
1. You know well that the "no selection scenario" is not realistic, but
your point that selection is *unnecesary* for evolution seems reasonable.
Selection appears to act as a moderating influence, culling out those
lineages that fail in some way to achieve reproductive success.
2. You say, "Suppose we reproduce it,
with exactly the kinds of "random" (i.e., purposeless) variations that
in natural genome replication....
I would challenge your equating 'random' with 'purposeless.' I (and others)
have used the following analogy to demonstrate that. Suppose there were a
perfectly honest casino--every role of the dice, spin of the wheel, turn of
the card, etc., perfectly random. Yet at the end of the day, the owners of
the casino can be assured of a handsome profit. Why? Because the owners
have used the perfect randomness of these individual events (and their
associated probabilities) in their calculations of the payout rates. In
other words, perfect randomness in individual events has been purposefully
employed in a larger context. Bottom line: randomness does NOT translate
into purposelessness. Questions of purpose, whether in casino game outcomes
or in speciation dynamics, require a larger context of consideration.
3. Let me put another face on random variation (with or without selection).
I see the universe as a Creation that has been given being by a Creator. As
such, everything that the Creation is and everything that it is capable of
doing is a part of the being that was given to it by the Creator. I am
perfectly happy to entertain the possibility (likelihood) that this
Creation is fully equipped with all of the requisite formational
capabilities to make something as remarkable as biotic evolution possible.
In the context of this perspective, another aspect of the Creation's being
is a robust set of potentialities for viable forms of life. I see this
"potentiality space" for life forms as another 'gift of being' given to the
Creation by its Creator. Because the robustness of this potentiality space
is indicative of the Creator's creativity, I have high expectations
regarding both the richness of this space and the Creation's capabilities
for moving through it. In that context, then, random variation will be
recognized as an effective means of exploring potentiality space. If it is
the Creator's intention that the Creation move through its potentiality
space of viable life forms in the course of time, then random variation
would be functioning as a means of achieving that purpose.
Once again, 'random' cannot be simplistically equated with 'purposeless.'
Howard Van Till