Tonight I read “Does Origins of Life
Research Rest on a Mistake?” by Roger White (NOUS 41:3 (2007) 453–477). Nagel refers to this paper and White refers
back to conversations with Nagel. It is
a very interesting read.
White challenges a basic
assumption that is apparently shared by almost all of those scientists who are
trying to explain the origin of life.
Darwinian theory does very well at explaining the emergence of more
complex and varied forms of life from simpler forms. It depends, however, on the existence of
self-replicating molecules that can come under the influence of natural
selection. What can explain the origin
of the self-replicators?
White presents the alternatives
with an elegant metaphor: the three pebble patterns.
Pebble Pattern 1: Pebbles are scattered in a disorderly
fashion as we typically find them on the sidewalk.
Pebble Pattern 2: At the English seaside, pebbles cover the
beach in descending order of size toward the shoreline
Pebble Pattern 3: The pebbles are arranged to form a stick
figure with a smile on its face.
Pattern 1 requires no explanation
other than chance. Random forces acting
on the initial state (the prior position of the pebbles) produced the current
state. Call this the chance
explanation.
Pattern 2 shows a coherent
pattern that does call for an explanation that involves more than chance. The action of wind and wave select out
heavier and lighter pebbles and place them accordingly. Unlike the previous example, where the
resulting state is largely dependent on the initial position of the pebbles, in
this example it doesn’t matter much how the pebbles were distributed
initially. The forces at work will move
them toward the same arrangement. White
calls this “unintentional biasing”.
Pattern 3 shows clear evidence
of intentional biasing. Anyone looking
at the stick figure will assume that someone intentionally arranged it to make
a picture.
White informs us that almost
all of the origin of life theorists reject the chance explanation for the
origin of the proto-organic molecules from which all living organisms
descended. The reason is that the
emergence of such molecules by chance seems absurdly improbable.
We require one kind of chemical to be present, plus another
very different one , and yet another different one , and we require the absence
of still other substances. Certain chemical reactions must take place, then
others involving different ingredients and producing different outcomes. A wide
variety of events that would undermine the whole process must fail to occur.
The molecular parts required to make up the replication machinery come in
various sizes and structures. And they are not arranged in anything like a simple
repetitive pattern but rather each has a very unique position and role to play.
Add to that the fact that the
window of time in which this had to take place seems woefully inadequate to
those that have looked at the problem with expertise. To appeal to a familiar metaphor, the
emergence of self-replicating organisms in the history of this planet is about
as plausible as an army of chimpanzees, randomly striking their keyboard, turning
out a copy of Richard III before lunch.
Neither can the origin of life
theorists appeal to intentional biasing (which is to say, intelligent design)
as that seems strictly outside the realm of science. So they have to believe in some form of
unintentional biasing. Something in the
nature of the planet (and hence of the Kosmos) was biased in favor of the
emergence of life just the tides are biased in favor of a certain arrangement
of pebbles.
White does not indicate whether
he accepts the view that the appearance of self-replicating chemicals was as
improbable as I put it above. He just
points out that most theorists regard it as so.
His thesis is that the only
reason to reject the chance hypothesis is that life looks like something that was intentionally designed and that fact provides
no reason to believe in any natural, unintentional biasing mechanisms. If I win the lottery despite implausible
odds, I may feel as though I had been somehow favored over chance; it makes no
case that the lottery is biased, intentionally or otherwise.
I suspect that White is
inclined toward the chance hypothesis.
Those of us who cannot buy it are only lottery winner who cannot believe
that in our own good luck. If the
consensus is correct that luck is an implausible explanation, then his
reasoning points in the direction of intentional biasing. That pushes my theometer a couple of clicks in the direction of yes.
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