Darwinism: Science or Philosophy - Chapter 12

Doubts About Darwinism

by Peter van Inwagen
1994

Response to this paper.


AT THIS SYMPOSIUM we have been asked to speak on the following thesis:
Darwinism and neo-Darwinism as generally held and taught in our society
carry with them an a priori commitment to metaphysical naturalism, which
is essential to make a convincing case on their behalf.

In order to have a label for them, I will call these words "the
Quotation." I have thought about the Quotation, and I have decided that I
cannot assent to it-although I by no means reject it. I have two reasons.
First, I don't fully understand it, and, second, however it is to be
interpreted, it is clear to me that I am not in a position to make
judgments about it, owing to sheer factual ignorance.

I will take up the second point first. My ignorance pertains to the words
"as generally held and taught in our society" I am not a sociologist of
science, or of education, and I don't claim to know how any particular
doctrine or theory is generally held and taught in our society. I admit
that I've seen lot of individual bits of evidence, such as a cell
biologist's quotation of a letter he was sent by a publisher telling him
that a proposed textbook chapter on the origin of life should make it
clear that "God is an unnecessary hypothesis," but I think I'll leave this
aspect of the question alone.

As to my failure fully to understand the Quotation, this has mainly to do
with the fact that different people use words in different ways, and I am
not sure how the terms Darwinism (much less neo-Darwinism), metaphysical
naturalism, and a priori are understood by the author of the Quotation.
Each of those terms could mean more than one thing, and I know from
experience that precision of meaning is important in questions about what
carries commitment to what.

Although I cannot assent to the Quotation, it does not arouse in me any
intellectual revulsion, but rather a sense of intellectual sympathy, a
feeling that if I were to explain what I believed about the matters it
touches on, someone who unreservedly agreed with it might well conclude
that he and I were on essentially the same side, even if I were
regrettably obtuse about several important issues. Those whose visceral
reaction to the Quotation is revulsion would probably feel that I was
essentially on the other side, one of the enemy. Let me explain what I
believe about these matters and why I think that what I believe is true,
and we shall see.

What I am going to say is perilously close to autobiography. I am not an
expert on anything having to do with Darwinism. I am not even a
well-informed amateur. I am just an intelligent guy who has read a few
books-a very dangerous type in the world of science and scholarship, as we
all know. (On the other hand, I have to point out that we are not talking
about superstring theory here. The issues involved don't seem to me to be
all that difficult to grasp-which is what intelligent guys who have read a
few books always think.)

If you are an expert, there is only one reason you might want to pay
attention to what I have to say. I am your public. If you are an expert
who doesn't care what the public thinks about evolution and related
matters, then you can stop reading right now. But, some experts do care
what the public thinks about these things. If you are one of them, and if
you think I'm wrong, I can at least tell you what it would take to
convince me that you're right and I'm wrong. Then you can write me off as
unteachable, or try to show me that other things than those I have
mentioned should convince me that you're right and I'm wrong. Or you can
try to do the things that I have said would convince me, or whatever takes
your fancy.

I'll start by explaining how I understand "Darwinism," which seems to be
the key term in these discussions. Darwinism is a theory about evolution,
so I'll explain how I understand the term evolution. Rather than try to
mark out a certain process or phenomenon that I propose to designate by
this name, I'll present a series of propositions I shall describe as
together constituting the thesis that evolution occurs or has occurred or
is real or whatever predicate believers in evolution should use. I won't
be too particular about which processes referred to in these propositions
are the ones that make up the phenomenon called evolution. Since I confine
the scope of my remarks to our planet, some may prefer to call my
discussion "the thesis of terrestrial evolution." Here are the first two
propositions:

Any two living organisms, past or present, have a common ancestor. There
have been living organisms for a very long time, not just for a few
thousand years but for millions of thousands of years-perhaps since a few
hundreds of millions of years after the earth's surface was cool enough to
support life. These two propositions taken together make up a rather weak
thesis. For one thing, it is weak because it says nothing about biological
diversity. This thesis could be true even if the only organisms there had
ever been were a particular sort of bacterium that had persisted unchanged
for billions of years. This thesis is weak also because it says almost
nothing about causation-although "ancestor" is a causal concept. It is
compatible, for example, with the statement that God has been responsible
for a vast array of miraculous innovations in the history of life. It is
also compatible with the statement that intelligent extraterrestrials have
been dropping in on the earth every ten million years or so to perform
prodigies of genetic engineering in aid of some mysterious agenda
involving terrestrial life. To get a more interesting thesis to associate
with the word evolution, let us add some propositions about diversity and
causation.

Life exhibits (and has exhibited for a very long time) enormous taxonomic
diversity. Only natural causes have been at work in the production of all
this diversity. What does natural mean? Well, the word can be opposed both
to miraculous or supernatural on the one hand, and to artificial on the
other. Let us understand natural in this context as carrying both
implications. The thesis of evolution implies that only the laws of
physics (operating of course under an enormously complex set of boundary
conditions) have been at work in the terrestrial biosphere during the
course of the diversification of life. It also implies that the only
extraterrestrial influences on terrestrial life have been things that are
in no way the instruments of intelligence or purpose: light from the sun,
cosmic rays, falls of meteor dust, asteroid strikes, and the like.
I think it is useful to regard these four propositions as together
constituting the thesis of evolution. (Should there be something here
suggestive of the notion of "progress," or, at any rate, of increasing
complexity? Anyone who thinks so may add a clause to the effect that, in
the very long run, the complexity of both the biosphere and of the most
complex organisms in the biosphere tends to increase. I would not object
to the addition. This seems to be a part of what a lot of people mean by
evolution, and it seems to be true.)

I take Darwinism to be an identification of the "natural causes" referred
to in the last of the four propositions I take Darwinism to be a
specification of a mechanism, a single mechanism, that explains taxonomic
diversification. This mechanism is the operation of natural selection on
random small hereditable variations that come about in the course of
reproduction.

I am not, in a paper of this scope, going to try to give an exposition of
what lies behind the slogan "the operation of natural selection on random
small hereditable variations." I know that there is considerable diversity
of opinion among those who describe themselves as Darwinians as to how the
reality behind the slogan should be spelled out in detail, but I don't
think that these disagreements have much to do with what l want to say. At
any rate, I take it that we all have some idea of what these words mean.
Even the slogan is too cumbersome for frequent repetition, so I'll call
the mechanism simply "natural selection."

Darwinism, then, is the thesis of evolution plus the further thesis that
the sole mechanism behind the enormous taxonomic diversity displayed by
terrestrial life-behind the existence of all of those vastly different
phyla and orders and classes-is natural selection. (I am aware that Darwin
was probably not a Darwinian in this sense, and I am aware that he
sometimes opposed natural selection to sexual selection. As to the former
point, I am trying to capture at least something close to the most Usual
sense the word Darwinism has in current debates. As to the latter point,
unless I am mistaken, most people today use the term natural selection in
such a way that what Darwin called sexual selection is a special case of
natural selection.)

Now where do I stand on all of this?

First, I accept the thesis of evolution. More exactly, I accept evolution
with the exception of our own species, and even in that one very special
case. I don't rule it out but merely suspend judgment. But I don't want to
talk about humanity, which is a very special case. As a general thesis
about taxonomic diversity. I accept the evolutionary thesis.

For example, I accept the thesis that my cat and the spider she is playing
with have a common ancestor. For that matter, I believe that my cat and
the spider and I have a common ancestor. To make a long story short, this
seems to be the best explanation of apparently arbitrary features we have
in common: the pentadactyl limb structure that the cat and I share and the
genetic code that all three of us share with the algae and yeasts. I don't
mean to imply that the "shared arbitrary features" argument is the only
good argument for the common ancestry thesis. And I don't doubt that the
lines of descent from their common ancestor to my cat and the spider
involved only natural causes. To make a long story short, I believe this
because I make it a rule to believe that an event or process has natural
causes unless there is some reason to think otherwise, and, in the case of
my cat and the spider, there seems to be no reason to think otherwise.
I accept the thesis that natural selection is one of the mechanisms
connected with the existence of biological diversity. It has certainly
been demonstrated that natural selection is a real phenomenon, a mechanism
that actually operates in nature, and I see no reason to doubt that it is
at least among the causal "inputs" that have produced the diversity of
terrestrial life.

I accept the thesis that Darwinism is a genuine empirical hypothesis, and
not a tautology. It is certainly true that there have been attempts to
formulate Darwinism that look a lot like "in the long run, organisms that
have the capacity for having the most descendants will probably have the
most descendants," but I take these attempts to be simply failed attempts
at formulating Darwinism. Whatever else Darwinism may imply, it implies
that natural selection has-"all by itself," so to speak, without help from
other mechanisms or miracles or intelligent extraterrestrials-produced
enormous taxonomic diversity, and has done so within a certain measurable
span of time. Darwinism therefore implies that natural selection is
capable of doing that sort of thing, and of doing it "all by itself."

This fact suggests a thought-experiment. Suppose that we seed the oceans
of millions of planets that are lifeless but suitable for life with
artificial prokaryotic organisms. Suppose that these organisms have no
features that would make for taxonomic diversity among their descendants
other than the fact that they reproduce themselves with random small
hereditable variations. (We know this because we have made them to have
just that feature.) I believe that Darwinism predicts that on at least a
significant proportion of these planets, we shall eventually observe
biological diversity comparable with that of the present-day terrestrial
biosphere: cells with nuclei, photosynthesis, multicellular organisms,
sexual dimorphism, many phyla, and so on. Or perhaps we shall observe
other kinds of diversity, equally striking, but without terrestrial
analogue. ("Eventually"? Well, if the experiment proceeded without result
for half the main-sequence lifetime of a type G star, it would then be
reasonable for the granting agency to refuse further funding.)

This thought-experiment cannot be performed, but its conceivability shows
that Darwinism is not in any sense a tautology, since the predicted result
does not follow from the meaning of "natural selection" or the meanings of
any other words: it is perfectly possible to imagine the experiment
failing. I note in passing that its failure would not refute Darwinism-I
agree with the common view that no experiment can conclusively refute a
theory-but it would certainly imply that the Darwinians had some
explaining to do, and that is just the kind of leverage that experimental
results are supposed to have in relation to theories with genuine
empirical content.

Darwinism clearly makes this prediction, and there is certainly no
evidence that this prediction is not right But it seems to make others,
and there is evidence that some of those are not right. Darwinism seems to
predict that the history of life will look a certain way: there will be
few if any sharp "breaks" in that history (perhaps a few sudden
extinctions of geographically confined species or genuses).
To give some intuitive sense to this prediction, suppose that we could
see, laid out on a long strip of paper, a detailed picture of the father
of a certain elephant, and the father of that elephant, and the father of
that elephant, and so on. The "absence of sharp breaks" means that over
millions of generations, we should see only very gradual change. A million
generations ago, the animal depicted on the strip would not look very much
like an elephant, but any hundred-generation section of the strip would
contain only animals that looked very, very similar. And, of course, this
point is intended to apply not only to elephants but to the members of any
species or genus. The point applies also not to species and genuses but to
any taxon: A long enough strip that starts its backward journey with a
picture of a snake will somewhere contain a picture of a fish, although
any hundred-generation section of the strip will contain pictures of only
very similar animals.

We do not have the strip. But we do have the inevitably much less
satisfactory fossil record, and it is well known that this record does not
show species gradually, almost imperceptibly, shading into others as our
gaze extends backward in time. As regards the broader taxa, we do not
observe any line of descent that starts with, say, certain fish, and ends
among the first amphibians, the members of this line becoming less and
less fishy with the passage of time and acquiring more and more of the
characteristics of amphibians, the intermediate members of the line being
neither fish nor frog nor good red herring. Rather, we see sharp
discontinuities-sharp at least as sharpness is measured on the geological
time-scale, for what looks like a sudden discontinuity in the fossil
record could well encompass many thousands of successive generations of
organisms.

It is also well known that Darwin was troubled by the apparent
discontinuities and lack of intermediate forms in the fossil record. Since
Darwin's day these features have not disappeared in the light of new
fossil discoveries but have become more and more evident.
On the surface, then, it looks as if Darwinism makes wrong predictions
about the fossil record. But, as is usual in cases of an attractive
scientific hypothesis that appears to be in conflict with some body of
evidence, it is possible to devise "auxiliary hypotheses" that explain the
apparent incompatibility. This has been done, if by no one else, by Gould
and Eldredge, with their hypothesis that diversification takes place very
rapidly among populations of peripheral isolates. As is usual in such
cases, many scientists have insisted that this was just what everyone had
believed all along.

When such an auxiliary hypothesis is proposed, some standard questions
have to be asked: is it coherent? Is it well motivated? Does it actually
succeed in saving both the theory and the phenomena? Is the sole reason
for accepting it that it saves the theory and the phenomena, or does it
have something else going for it? Does the theory plus the hypothesis
suggest experiments or observations that are not suggested by the theory
itself?

Those are large questions. I am neither a biologist nor a philosopher of
biology, and I am out of my depth here. But, speaking not as someone who
claims to know anything but just as a member of the interested public, I
have to say that I have not been convinced by the attempts I know of to
answer them. I suppose that the main reason I am not convinced is that I
am not convinced that the required intermediates are, in all cases anyway,
anatomically and physiologically possible. I am not sure that a true
amphibian, say, could be descended from a true fish across a few score
thousands of generations by the small steps that Darwinism allows. I am
not sure that you could take a particular fish and make a few changes in
its genotype and then a few more changes and then a few more changes, and,
after a few score thousand of such small sets of changes, end up with the
genotype of an amphibian-not if : each intermediate genotype has to be the
genotype of a viable organism, and not if "a few changes" means changes of
the magnitude that typically separate an organism and one of its offspring.
Let's call what I'm skeptical about the existence of "short paths": short,
baby-step genetic paths between organisms belonging to, say, different
biological classes. I am also skeptical about how many short paths exist
as abstract possibilities, given that any do at all-since even if there
were short paths, there might be so few of them that it would be vastly
improbable that any of them would actually get taken.

Presumably, since most biologists are Darwinians of some stripe, most
biologists believe that short paths exist and are numerous enough as
abstract possibilities that it is not at all surprising that quite a few
would actually be taken. What I should like to know more about is this: Is
this belief of theirs grounded in their nuts-and-bolts knowledge of
anatomy, physiology, and molecular biology? Or is it grounded simply in
the fact that its truth is required by Darwinism? Unless there is some
reason to believe in the existence of short paths that is prior to and
independent of Darwinism, I am going to continue to be skeptical about
Darwinism.

Let me recall two well-known episodes from the history of science. Newton
believed that interplanetary gravitational forces rendered the solar
system unstable, that, owing to cumulative distortions of the orbits of
the planets by the gravitational fields of the other planets, the solar
system could not retain its dynamic stability for more than a few
centuries. He dealt with this difficulty by postulating periodic divine
corrections of the planetary orbits. To remove a red herring, let us
pretend that he postulated not miraculous interference in the course of
nature, but rather the action of some as yet unknown physical principle,
in addition to the laws of motion and the law of universal gravitation. A
generation or so after Newton, Laplace showed that the destabilizing
effects of mutual planetary gravitational attraction that Newton worried
about tended to cancel out, and that, although a solar system whose
motions were governed solely by the laws of motion and gravitation was
perhaps not absolutely stable, it would be capable of retaining its
stability over vast stretches of time.

Lord Kelvin insisted that, despite what the paleontologists said, the sun
could not have been shining at its present luminosity for more than a
score or so millions of years. This was because that is the longest period
you could get on any reasonable initial conditions if solar radiation was,
as he supposed, due entirely to the release of gravitational potential
energy in the form of radiation as the material of the sun underwent
gravitational contraction.

In my view, owing to the difficulties I have briefly mentioned, Darwinism
is in the position either of classical celestial mechanics in the time of
Newton, or else in the position of the standard late-nineteenth century
theory of solar radiation that Kelvin appealed to. In each case the theory
appears to make the wrong predictions about the observed phenomenon.
Newton knew it. Kelvin denied it, dismissing the claims of paleontology as
confidently as any twentieth century "creation scientist." In the case of
Newton and Laplace, the difficulty was surmountable, although surmounting
it was by no means trivial. It required all the resources of one of the
greatest applied mathematicians in history. In the latter case, the
difficulty was insurmountable. Kelvin's proposed mechanism (the
transformation of gravitational potential energy to radiant energy) is
there all right, but it is one of several mechanisms that contribute to
solar radiation, and the others are responsible for the lion's share of
the effect. Lord Kelvin's implicit theory, that only the one mechanism was
at work, was wrong.

Which of these cases represents the situation of Darwinism? Well, I am
inclined to think the second. Those who say that there is no problem are
in roughly the position of Lord Kelvin vis-a-vis the data of paleontology.
If the situation of Darwinism is analogous to the first case, we do not
now know this. In that event, evolution has had in Darwin its Newton, but
it has not yet had its Laplace. If the situation of Darwinism is analogous
to the second case, then there are as yet undiscovered evolutionary
mechanisms, ones that contribute the lion's share of the effect. (I should
mention that the analogies I have been appealing to have at least one
serious defect. Classical gravitational mechanics is a quantitative
theory, and it is pretty clear what its predictions are. It is not the
fault of Darwinism that it is not a quantitative theory, but the fact that
it is not does have the consequence that it is much less clear what its
predictions are.)

I am not quite finished with the case of Lord Kelvin. Before leaving it, I
want to use it as a stick with which to beat the following argument: "No
one should say that evolution requires other mechanisms than natural
selection unless he or she has some constructive proposal to make about
what those mechanisms might be." I have heard somewhere that, as a matter
of fact, some paleontologists did rather timidly ask Kelvin whether there
might be some unknown factor involved in the production of solar
radiation. His reply was evidently contemptuous and dismissive. He might
well have used an argument exactly parallel to the one we are considering:
You shouldn't make that suggestion unless you have some constructive
proposal to make about what that factor might be. If he had said this, he
would have been wrong. He should have been willing to admit that
paleontological evidence, in conjunction with his own calculations,
established at least a very strong prima facie case for the conclusion
that some factor other than gravitational contraction was partly
responsible for the sun's energy output. He should have been willing to
admit this despite the fact that no physicist, and certainly no
paleontologist, had any constructive suggestion about what that factor
might be. (We know now that any speculation about this question at the
turn of the twentieth century would have been a waste of time.)
So that is where I stand. It looks to me as if natural selection is not a
complete explanation of the diversity of life. I am inclined to think that
its primary 'function," if I may use that word, is to insure that species
possess sufficient diachronic flexibility that they aren't just
automatically wiped out by the first environmental change that comes
along. And, of course, natural selection is a very efficient fine-tuning
mechanism: once a species has found an ecological niche for itself,
natural selection tends to optimize its "fit" into that niche.

And I am willing to allow a little more to natural selection than this. I
am inclined to think that "unaided" natural selection can produce new
species; I have a very hard time believing that it can produce, say, new
classes. There are (or so it looks from where I stand-not much of a
vantage-point, I admit) mechanisms involved in biological diversification
that are as unknown, and probably as unguessable, today as the release of
surplus binding energy in nuclear fusion was in the year 1900. (But I
don't mean to suggest that these mechanisms involve new physical
principles.) It looks to me as if Darwinians are like someone who, having
observed that tugboats sometimes maneuver ocean liners in tight places by
directing high-pressure streams of water at them, concludes that he has
discovered the method by which the liners cross the Atlantic.

Now a concluding even more unscientific postscript, connecting what I have
said so far with my religious views. Like St. Augustine, I am not a
literalist about the first three chapters of Genesis. Writing early in the
fifth century, Augustine held that the six "days" of creation in Genesis
were not meant to be taken as literal twenty-four hour days, but were a
rhetorical figure used to describe six aspects of creation. He held that
in the beginning the world contained much less actual order than it does
today, and that the order we now observe in the world evolved- that is,
"unfolded"-out of the potential order that God had placed in things at the
moment of creation. This would be my view as well. I see it as the
business of science to uncover the mechanisms of that unfolding.
As to biological order, if unaided natural selection really is capable of
producing the ordered diversity we see in the terrestrial biosphere today,
I see no reason why a God who wanted such ordered diversity should not
have used this very elegant mechanism. If I doubt that God did this, it is
only because I doubt that unaided natural selection could do the job. I
think that other mechanisms would be required and that he therefore must
have used them. But if unaided natural selection would work-well, why
shouldn't God use something that would work?

It seems to be a widespread opinion that something about natural selection
unfits it for use as a divine instrument. I have never been able to see
this. When I was an agnostic, I was a Darwinian. When I became a
Christian, a very old-fashioned, orthodox one, I was a Darwinian still.
And although I have experienced many intellectual difficulties with my
faith, my belief in Darwinism never caused me the least intellectual
discomfort. My doubts about Darwinism began only when I discovered that
the "smoothness" of the fossil record that I had always believed in was
not there. I should add, in this connection, that I do not regard the
difficulties that I believe Darwinism faces as constituting any sort of
evidence of theism. I think that the truth or falsity of Darwinism has no
more to do with theism than does, say, the hypothesis of continental drift.

But many people do not see things this way, I could quote both Darwinians
and anti-Darwinians to this effect. Here is a famous quotation from Monod
that will do as well as any. Speaking of the events that have been
identified as the sources of mutations, he says:

We call these events accidental; we say that they are random
occurrences. And since they constitute the only possible source of
modifications in the genetic text, itself the sole repository of the
organism's hereditary structure, it necessarily follows that chance
alone is at the source of every innovation, of all creation in the
biosphere. Pure chance, absolutely free but blind, at the very root of
the stupendous edifice of evolution: this central concept of modern
biology . . . is today the sole conceivable hypothesis, the only one
that squares with observed and tested fact.{1}

Monod goes on to make clear that he understands chance in Aristotle's
sense, as arising from the coincidence of independent lines of causation.
(Thus, it is due to chance that Shakespeare and Cervantes died on the same
day, as it would not be if they had killed each other in a duel. In this
sense, chance can exist even in a fully deterministic world.) He
identifies the source of this chance with imperfections in the fundamental
mechanisms of molecular invariance in living organisms. He mentions only
the causes of mutations, but he might have mentioned other sorts of events
that are of evolutionary significance and can with equal plausibility be
ascribed to chance: the flood that happened to destroy a certain herd of
ruminants, the raising by geological forces of a land bridge that enabled
representatives of certain species to move into a new environment, the
intersection of the trajectories of the earth and a certain comet, and so
on.

I don't quite see how it is that the hypothesis that all such events are
due to chance is the only conceivable hypothesis. But let us suppose that
this hypothesis is at any rate true. Does it follow that the general
features of the biosphere are products of chance? It does not. To suppose
that they are would be to commit the so-called fallacy of composition. It
would be as if one reasoned that because a cow is entirely composed of
quarks and electrons, and quarks and electrons are nonliving and
invisible, a cow must therefore be nonliving and invisible.

There is a marvelous device for calculating the areas surrounded by
irregular closed curves. It is an electronic realization of what is
sometimes called the dartboard technique. To simplify somewhat: you draw
the curve on a screen; then the device selects points on the screen at
random, and looks to see whether or not each point falls inside the curve;
as the number of points chosen increases, the ratio of the chosen points
that fall inside the curve to the total number of chosen points tends to
the ratio of the area enclosed by the curve to the area of the screen. For
a large class of curves, including all that you could draw by hand, and
probably all that would be of practical interest to scientists or
engineers, the convergence of ratios is quite rapid. Because of this, such
devices are useful and have been built. Now the properties of each point
that is chosen, its coordinates, are products of chance in just Monod's
sense. But the whole assemblage of points chosen in the course of solving
a given area problem has an important property that is not due to chance:
its capacity to represent the area of a curve that had been drawn before
any of the points was chosen.

Indeed, since the device was built by purposive beings, there can be no
objection to saying that the whole assemblage of points has the purpose of
representing the area of that curve-despite the fact that the coordinates
of each individual point have no purpose whatever. It is also true that
the fact that each point has coordinates that are due to chance is not due
to chance and has a purpose: its purpose is the elimination of bias, to
insure that the probability of a given point's falling inside the curve
depends on the proportion of the screen enclosed by the curve and on
nothing else.

Suppose that every mutation that has ever occurred is, as Monod says, due
to chance. Suppose, in fact, that every individual event of any kind that
is a part of the causal history of the biosphere is due to chance. It does
not follow that every aspect of the biosphere is due to chance. And if
none of these individual events has a purpose, it does not follow that the
biosphere has no purpose. To make either inference is to commit the
fallacy of composition

Now this reasoning shows at most that the thesis that some features of the
biosphere are not due to chance (and likewise the stronger thesis that
they have a purpose) is logically consistent with Darwinism. It could
still be that the conditional probability of the thesis that there are
features of the biosphere that are not due to chance is very low, even
negligible, on the hypothesis of Darwinism, But the reasoning does show
that if someone wants to construct an argument for the conclusion that
Darwinism is in any sense incompatible with the thesis that some features
of the biosphere are not products of chance, he or she will have to employ
some premise in addition to "Darwinism implies that all events of
evolutionary significance are due to chance " And, as I have implied, I do
not find that premise itself indisputable.

One argument might be that the features of the biosphere are in a very
important respect unlike the features of an assemblage of points produced
by our area-measuring device. Each time we draw a cube on the screen of
the area-measurer and turn the thing on, it is for all practical purposes
determined, foreordained, that the assemblage of points it produces will
have the property of representing the area enclosed by the curve
But, it might be argued, the properties of the biosphere are not like
that. There used to be a popular thesis called Biochemical Predestination,
according to which they were like that. According to Biochemical
Predestination, you just take a lifeless planet that satisfies certain
conditions (conditions the earth satisfied before there was any life on
it, and which are undemanding enough that it would be reasonable to
suppose that a pretty fair number of planets in a given galaxy satisfied
them) and in due course you will "automatically" have life, eukaryotic
life, multicellular life, sexually dimorphic life, highly differentiated
life, and, finally, intelligent life-the whole Star Trek scenario.
Biochemical Predestination does not seem to be very popular among the
practitioners of the life sciences these days, although belief in it seems
to be common among physicists and astronomers and nearly universal among
university undergraduates, who believe that Vulcans and Klingons await us
among the stars with the same unreflective assurance that attended the
belief of their twenty-times-great grandparents that elves and trolls
awaited them in the woods. But if Biochemical Predestination is not true,
if the main features of the biosphere did not fall into place

automatically, but rather are due to remote chances that just happened to
come off then how can it be that these features are due to the purposes of
a divine being-or any intelligent being? In short, the failure of
Biochemical Predestination shows that, since the evolutionary process has
no determinate "output," it is not the kind of thing that could be
anyone's instrument.

Curiously enough, Biochemical Predestination was said by those who
believed in it to show that the evolutionary process was not anyone's
instrument, owing to the fact that, according to that hypothesis, the
features of the biosphere are a consequence of the laws of physics
operating on the matter near the surface of the earth, and have therefore
been produced without any need for manipulation by outside forces.
Moreover, since these same features would have emerged from almost any set
of initial conditions, they have been produced without any need for any
sort of initial adjustment or fine-tuning of the state of the matter near
the surface of the earth.

I don't myself see the force of either of these ideas. I don't see why
either Biochemical Predestination or its denial should be thought to have
any theological (or atheological) implications. Perhaps what is needed in
order for there to be a useful discussion of the question whether there
are such implications is some measure of agreement about what a biosphere
that was a divine creation would look like: what it would look like at any
given point in time, and what its history would look like. After all, if
you propose to refute an hypothesis by an appeal to observation, you have
to have some idea about what things would look like if that hypothesis
were true.

I myself have almost no expectations about what a divinely created
biosphere would look like. I mean I have no a priori expectations. Since I
think that the biosphere is in fact a divine creation, I of course think I
know one thing a divinely created biosphere might look like: what it does
look like. How should I know what features to expect a biosphere to have
if that biosphere were created by a being whose knowledge and wisdom were
unlimited and whose power was limited only by considerations of what is
intrinsically possible? Before I could make even a guess, I should have to
know what that being wanted the biosphere for, and I should have to know a
lot more than I do about what is intrinsically possible. I don't see how
anyone could know what a divine being wanted a biosphere for-not unless
the divine being told him, anyway. And I doubt whether anyone knows much
more than I do-much more than almost nothing at all-about what is
intrinsically possible.

NOTE

{1} Jacques Monod, Chance and Necessity: An Essay on the Natural
Philosophy of Modern Biology, tr. Austryn Wainhouse (New York: Vintage
Books, 1971), pp. 112-113.

Foundation for Thought and Ethics.

Copies of the book Darwinism: Science or Philosophy are available from:
Foundation for Thought and Ethics