But
there is a huge problem with such an explanation. Accumulations are
unorganized things; a thesaurus lists “pile” and “heap” as
synonyms. But what we have in the human body are fantastically organized systems showing the highest order, coordination and functional
coherence. It would seem to make no sense at all to speak of such
systems as mere “accumulations.”
Darwin did nothing to explain how random changes could achieve any high level of organization, let alone the gigantic degree of organization we see in the human body. Neither Darwin nor any Darwinist has ever explained how natural selection and random changes could ever cause biological parts to become well organized. There is no good evidence that any complex visible biological innovation ever appeared because of random mutations and natural selection, and such an idea is essentially an article of faith in a modern-day secular creed.
In
Chapter 7 of the sixth edition of On the Origin of Species, which you can read here, Darwin addresses various
objections to his theory. On page 170 he states, “A much more
serious objection has been urged by Bronn, and recently by Broca,
namely, that many characters appear to be of no service whatsoever to
their possessors, and therefore cannot have been influenced through
natural selection.” Darwin concedes on the next page that “there
is much force to the above objection.” We can state the objection
like this: many types of plant and animal species, in particular
mankind, have major characteristics that do not add to their survival
value, and which therefore cannot have arisen because of natural
selection (which Darwin tells us works only to improve survival
value or the likelihood of reproduction). In many types of plants (in particular, flowers) we see a
vast host of features which rather seem to exist according to some
principle of diversity or ornamentation or beauty rather than some
principle of biological functionality. Using the term “the biology
of the baroque,” biologist Michael Denton has pointed out many examples
of non-adaptive features in biological organisms: things such as the
intricate shapes of maple leaves, the huge variety of colors in
butterfly wings, and peacock feathers.
In humanity we see many mental abilities and characteristics that seem to have no survival value for any organism existing in the wild, including spirituality, artistic creativity, philosophical reasoning ability, and mathematical ability. See here for a full discussion of such traits, and how they cannot be explained by natural selection. The co-founder of the theory of evolution by natural selection (Alfred Russel Wallace) wrote an essay stating that the theory could not explain some of the most important mental characteristics of mankind.
On
page 177 of the sixth edition of On the Origin of Species, Darwin discusses another
objection to his theory, saying, “The one new point which appears
to have struck many readers is, 'that natural selection is
incompetent to account for the incipient stages of useful
structures.'” This is the gravest objection to the credibility of
Darwin's explanation for biological complexity.
In
general Darwinism fails to explain the first stages of useful
structures. This was pointed out very clearly in Darwin's time by the
biologist Mivart, who wrote the following at the beginning of Chapter
II of his book On the Genesis of Species: "Natural
Selection utterly fails to account for the conservation and
development of the minute and rudimentary beginnings, the slight and
infinitesimal commencements of structures, however useful those
structures may later become." Mivart devoted Chapter II of that
book to many examples of "incipient stages" that Darwinism
could not explain well. You can read online Mivart's many examples here. Without even reading that, it is easy to think of many examples of incipient stages that would not be useful, such as the first small part of any limb (such as an arm or leg) or the first small part of a wing or the first
small part of a mammary gland. Other examples are the first small
part of a penis, testicle, or an ovary. On the microscopic level, there is the fact that the first small part of almost every protein molecule is useless.
What is very amusing in that each time a person tries to use the idea of exaptation to defend Darwinian explanations, he is twice appealing to purpose while trying to salvage a theory of purposeless biological origins. This is because the idea of exaptation or co-option is typically stated as the idea that some biological structure that existed for one purpose was then used by evolution for some other purpose. When someone uses such "double purpose" reasoning to defend a theory of purposeless biological origins, he is rather like a husband who swears to his wife that he has given up drinking, and then proposes that he and his wife drink a toast to his new sobriety -- not just a vodka toast but a good stiff whiskey toast also.
To try to defend against the objection that natural selection cannot account
for the incipient states or early stages of an innovation, Darwin
appealed to an idea that is now called co-option or exaptation. It is
the idea that a biological innovation can arise when evolution takes
advantage of something that had arisen for some other purpose, and uses it for a different purpose.
For
example, on page 189 of the sixth edition of On the Origin of Species, Darwin pointed out that Mivart had complained
that in their earliest stages, mammary glands would not have been
useful for providing milk for an infant:
Mr.
Mirvart asks: “It is conceivable that the young of any animal was
ever saved from destruction by accidentally sucking a drop of
scarcely nutritious fluid from an accidentally hypertropied cutaneous
gland of its mother? And even if one ever was so, what was the chance
of the perpetuation of such a variation?” But the case is not here
put fairly. It is admitted by most evolutionists that mammals are
descended from a marsupial form; and if so, the mammary glands will
have first been at first developed within the marsupial sack.
Here
Darwin was trying to use the idea of co-option, arguing that the
mammary glands in the breasts of mammals weren't too hard to develop,
because they were co-opted from glands in a pouch-like structure of
marsupials from which mammals are descended. But today's
evolutionary biologists do not maintain that mammals are descended
from marsupials. So this example by Darwin of a co-option now must be
dismissed as erroneous reasoning.
Darwin
also tried to use the swimbladder of fishes as an example of
co-option, implying that lungs were not too hard to develop, because
they developed from an earlier organ that existed for a different
purpose, for the purpose of helping some fish float. On page 147-148 of the sixth edition of On the Origin of Species, Darwin argued as followed:
The
illustration of the swimbladder in fishes is a good one, because it
shows us clearly the highly important fact that an organ originally
constructed for one purpose, namely, flotation, may be converted into
one for a widely different purpose, namely respiration....All
physiologists admit that the swimbladder is homologous or “ideally
similar” in position and structure with the lungs of the higher
vertebrate animals; hence there is no reason to doubt that the
swimbladder has actually been converted into lungs, or an organ used
exclusively for respiration.
But
this example of co-option or exaptation must also be placed in the
trash can. This is because modern evolutionary biologists tell us
that the first swim bladders appeared after the first lungs
appeared, not before them. The Wikipedia article on swim bladders
tells us, “Darwin reasoned that the lung in
air-breathing vertebrates had derived from a more primitive swim
bladder, but scientists now believe that the swim bladder derived
from a more primitive lung.”
Other
supposed cases of co-option or exaptation are not much better than
these cases. It is claimed that eyes evolved from organs derived for
a different purpose, the purpose of telling light from dark. But
this is not real co-option, because there would be no difference
between the most primitive type of vision and the ability to tell
light from dark. Place a few sheets of paper in front of your eyes,
and you have something that is both the weakest type of vision and
something allowing you to tell light from dark.
All
claims of exaptation or co-option on a large visible scale are
speculative. We have no proof at all that any single complex
biological innovation evolved from any previous biological structure
that served some different purpose. When scientists speculate that
flying feathers arose from feathers that appeared for the purpose of
attracting mates or keeping warm, they are just engaging in wild
guesses that don't sound credible. Even if such claims were true, they would have little force, since the origin of, say, a seductively attractive feather would be as hard-to-explain (from random mutations) as the origin of a feather for flying.
It
seems, in fact, that a Darwinist will be hard-pressed to produce a
single credible major case of co-option, in which evolution could have
conveniently converted one system or organ created for one purpose,
and used it for some other purpose. This should surprise no one. It
is, in fact, extremely rare for you to have a situation where a
complex object existing for one purpose can be conveniently converted
to serve some entirely different purpose. Examples of co-option are
few and far-between. There is a simple reason why this is so. In the
great majority of cases, once some object (whether biological or
inorganic) has been specialized to serve some particular purpose, it
then becomes so specialized that it is no longer possible to easily
adapt it to serve some very different purpose.
Looking
around my humble living quarters, I see the following objects: some
beds, some chairs, a sofa, an alarm clock, a fan, some book shelves,
a television, a cable box, some computers, a bicycle-type exercise
machine, two tables, some pots and pans, an oven, a refrigerator, a
dental irrigation device, some cell phones, some cameras, a video game console, a video game controller, a
flashlight, a hammer, an air conditioner, and an air
filter. Thinking about all of these things, I can find no case in
which any one of them could have been built from a simpler invention
which originated to serve some different purpose. Also I cannot think
of a single way in which I could extend or slightly modify any of these objects so that they could serve a different purpose.
If
parts or objects are specifically designed to be re-usable and to be
“building blocks,” then you might be able to use them for many
different purposes (Lego blocks are an example). But if something functional is
complex, and has not been specifically designed to be re-usable and
to be a kind of building block, it will tend to be so specialized
that it cannot be used for different purposes other than the special
purpose for which it originally existed. Co-option or exaptation (in
which evolution achieves some new purpose by using something “on
the shelf” which originated for some other purpose) is something that we
would not expect to happen other than very, very rarely.
A
simple example can show why appealing to co-option or exaptation is
not an effective defense against claims that natural selection and
random mutations could not produce very complex functional structures.
Let's say a person argues that it is too unlikely that a log cabin
would ever form in the woods by a random falling of logs. You might
try to defend against that claim by arguing that it wouldn't be too
hard, because an accidentally-forming log cabin might form from the much simpler structure called a lean-to, and that would be easier. But
this reasoning is fallacious. The overall probability of falling
logs forming first into a lean-to and then later into a full log
cabin would not be any greater than the probability of the log cabin
forming from falling logs in a way in which no lean-to existed while
the log cabin was forming. Similarly if it would require five lucky
random mutations to achieve some biological structure serving one
purpose, and then five other lucky random mutations for that
structure to be converted to serve some different purpose (call it
the second purpose), then overall achieving this second purpose would
not be much more likely than it would be if no such conversion
occurred, and you needed ten random mutations to achieve the
structure serving the second purpose.
I
can explain another general reason why the idea of co-option or
exaptation does not work in overcoming the problem that natural
selection cannot explain the incipient stages of complex innovations.
The reason is that in almost all cases in which we can imagine one
complex biological innovation (used for one purpose) changing into
some other biological innovation (used for some other purpose), there
would be a loss of functionality before there was an equally great
gain of functionality; and such a thing would be forbidden under
Darwinian assumptions.
In
almost all cases in which we can imagine some biological thing
gradually evolving from one function to another, there would be an
intermediate stage involving a decline in functionality. For
example, if some species with arms were to evolve so that the arms
became wings, that would be an example of co-option or exaptation.
But there would inevitably be an intermediate stage in which these
arms-becoming-wings were less useful as arms, but not yet useful as
wings. Such a state would involve an intermediate loss in overall
function.
Why
does this reality discredit the idea of exaptation as a widespread
occurrence in biology? According to Darwinian principles, evolution
or natural selection should never move some biological innovation
from one functional state to a less functional state. That's because
once the transition was made to a less functional state, the organism
would be less likely to survive; and organisms in such a state would
become less and less common in the population. If evolution had
precognition, and could foretell the future, there would be no
problem with imagining a scenario where some organ or appendage
(gradually changing over thousands or millions of years) goes from
being functional for reason X, to then being less functional, and
then to being functional for reason Y. But since evolution or
natural selection lacks any ability to foretell the future, such
transitions should not occur under Darwinian assumptions.
The
site https://www.biorxiv.org
is a server for preprints of biology papers. It stores preprints for very many thousands of biology papers (for example, when I searched for articles with "liver" in the title, I got 105 matches). Using the “Advanced search”
feature of this site, I searched for biology papers with “exaptation”
in the title. There was only one paper found. When I searched for
papers with “co-option” or “cooption” in the title -- a term
synonymous with “exaptation” – I found only seven papers. All of
these papers (which are highly speculative) refer only to claims of a co-option or exaptation on a microscropic level, typically one particular molecule or microorganism or gene. None of these papers claim to have found evidence for exaptation involving a visible structure. Evidently our biologists have actually been able to find very few substantive examples of exaptation, which shows that the idea of exaptation is
only a very weak and inadequate defense against the objection that
Darwinism cannot explain the beginning or incipient stages of complex
biological structures.
In almost all cases that we can imagine an incipient or beginning stage of a complex biological innovation, it is not true that we can find some other purpose that such a thing would have served. For example, no purpose would be served by one tenth of a vision system, one tenth of a circulatory system, one tenth of a reproductive system, one tenth of a digestive system, or one tenth of an arm or leg. In the rare cases in which a use can be found for a small fraction of a biological innovation, the incipient stages problem has still not been beat, because that fraction can always be halved, and almost always no use will be found for that smaller fraction. Show me a rare case where one fifth of some biological innovation is useful, and it will probably be a case where one tenth of such a biological innovation could not have been useful; and show me a rare case where one tenth of some biological innovation is useful, and it will probably be a case where one twentieth of such a biological innovation could not have been useful.
On the lowest useful level, organisms are made from protein molecules, and an average protein molecule in a human consists of about 500 amino acids arranged in just the right way to achieve a functional result. In almost all cases, there is a situation where a particular specialized protein molecule is useless if only half of the molecule exists or only a third of the molecule exists (partially because protein folding, required for proper protein function, is a very tricky thing to get right). Here the incipient stages problem exists to a mountainous degree, and the idea of exaptation is all but useless in lessening such a problem. Our biologists have no credible accounts of the origin of any of the more complex protein molecules, and they try to talk about such a topic as little as they can. This difficulty was unknown to Darwin, who had no idea that humans were built from more than 20,000 different types of fine-tuned protein molecules that would be so hard to explain, each one of these an impressive biological innovation.
In almost all cases that we can imagine an incipient or beginning stage of a complex biological innovation, it is not true that we can find some other purpose that such a thing would have served. For example, no purpose would be served by one tenth of a vision system, one tenth of a circulatory system, one tenth of a reproductive system, one tenth of a digestive system, or one tenth of an arm or leg. In the rare cases in which a use can be found for a small fraction of a biological innovation, the incipient stages problem has still not been beat, because that fraction can always be halved, and almost always no use will be found for that smaller fraction. Show me a rare case where one fifth of some biological innovation is useful, and it will probably be a case where one tenth of such a biological innovation could not have been useful; and show me a rare case where one tenth of some biological innovation is useful, and it will probably be a case where one twentieth of such a biological innovation could not have been useful.
On the lowest useful level, organisms are made from protein molecules, and an average protein molecule in a human consists of about 500 amino acids arranged in just the right way to achieve a functional result. In almost all cases, there is a situation where a particular specialized protein molecule is useless if only half of the molecule exists or only a third of the molecule exists (partially because protein folding, required for proper protein function, is a very tricky thing to get right). Here the incipient stages problem exists to a mountainous degree, and the idea of exaptation is all but useless in lessening such a problem. Our biologists have no credible accounts of the origin of any of the more complex protein molecules, and they try to talk about such a topic as little as they can. This difficulty was unknown to Darwin, who had no idea that humans were built from more than 20,000 different types of fine-tuned protein molecules that would be so hard to explain, each one of these an impressive biological innovation.
Our biologists tell us that random mutations and natural selection (the mere fact that fit organisms reproduce more) are sufficient to explain how blind nature was able to leap to stratospheric heights of biological organization and functional coherence. Similarly, a man might tell you that his herbal supplements and excellent athletic shoes can allow him to jump to the top of a cloud. When someone objects that natural selection and random mutations would never be remotely sufficient to cause the appearance of biological organisms more organized and complex than a 747 jet, our biologists say it's not too hard for such towering zeniths of biological organization to be reached, because leaps can be made from simpler things which existed for other purposes (the idea of exaptation or co-option). And similarly, the man with the excellent athletic shoes might tell you it's not too hard for him to jump to the top of a cloud, because rather than jumping all the way from the sidewalk, he can jump from the top of his roof.
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