Is the human pharynx poorly designed?
Countering the Critics
by Jerry Bergman
The concept of dysteleology claims that much poor design exists in the natural world,
and therefore an intelligent creator does not exist. A look at a supposed common
example of dysteleology, the design of the human pharynx, shows that it is in fact
evidence for superior design.
The dysteleology argument
Illuststration by Brenda Lindley Anderson
Cross section of the human pharynx showing the major structural parts involved in
breathing and swallowing.
The entire dysteleology argument is based on the recurrent assertion that there exist
many examples of poor design in the human body. As knowledge of life improves, dysteleology
claims have likewise been correspondingly disproved. The argument from dysteleology
is not scientific support for evolution, but, instead, is a claim about
the Creator’s attributes—what some people believe that God would or
would not do. This argument, for this reason, is theology, not science. Scientists speak theologically, not scientifically, when they imply that a competent creator would design a structure to be superior, they believe, to the existing design.
Dysteleology has become very popular among many Darwinists, not because it is based
on scientific evidence or on logic favouring evolutionism, but because it seems
to be a useful argument against intelligent design which appeals to popular opinion.
A problem with this argument is that Darwinists argue that the body is poorly designed,
and conversely they also argue that science cannot make judgments about design because
claims in this area are outside of science—judgments that science cannot entertain
because it assumes purpose in nature. Either science can make judgments
about design, or it cannot. Both cannot be true. One common claim of poor design
is the human pharynx.
Evolutionary claims
This argument is theology not science.
A noted zoologist teaching at a major university claimed that the human pharynx
is a poorly designed system, explicable only in terms of macroevolution. The example
he gives is designing a building with water and gas entering through a common chamber
so that whenever one is needed the other would have to be shut off. He claims this
design
‘ … would be the height of stupidity. But that is what your “intelligent
Creator” did when he designed and created man for, as you know, the pharynx
serves as a common passageway for air and water. Think of the number of lives that
have been lost by food or water getting into or obstructing the air passageway.
It certainly would have required very little intelligence for the Creator to have
designed a more efficient and less dangerous arrangement. … However, if you
trace the evolution of the head and especially the development of the food and respiratory
passageways from the fishes up through the amphibians, reptiles and early mammals
to man, you will note that the relationship turns out to be a masterpiece of evolutionary
achievement enabling aquatic organisms to become adapted to air breathing and thus
capable of living on land.’1
University of Michigan Professor Scott Atrain writes that the problem is the mouth
cavity in air breathing terrestrial animals
‘ … does double duty, as an opening to take in both food and air. As
creatures evolved from water onto land, the opening to the respiratory system was
jerry-rigged to share the preexisting digestive tract’s anterior structure,
including the mouth and pharynx [throat]. In terrestrial vertebrates, the pharynx
became a short passage linking the mouth to the esophagus and the windpipe. Any
mistiming of the swallowing mechanism that blocks off the air passage in routing
food to the esophagus causes choking.’2
Skybreak, in her new book endorsed by several notable evolutionists, including Richard
Leakey, P.Z. Myers and Kevin Padian, wrote that humans ‘have a dangerous tendency
to choke on food’ because the
‘ … passage that air follows to get to the lungs actually crosses
the path that food follows to get to the stomach. This would be an example of a
really stupid (or perversely sadistic) design if a god had actually designed
it that way! But this is not the result of anyone’s conscious “design”.
This choking problem simply reflects our own past evolutionary history: the breathing
channels of all land vertebrates also evolved in the distant past as modifications
of pre-existing structures (in this case the “air bladders”
of some bony fishes and lungfishes) which evolved into primitive lungs.’3
Analysis of the design
An analysis of the pharynx’s design eloquently proves that the claim of poor
design is false. In fact, the pharynx is an example of a superbly designed complex
system. The pharynx serves as a single passage for three systems—the respiratory,
digestive and communicative—for many very good reasons. A major one is, unlike
other primates, our airway and esophagus intersect. This can cause choking, but
allows speech.4
The pharynx is an example of a superbly designed complex system. The pharynx serves
as a single passage for three systems—the respiratory, digestive and communicative—for
many very good reasons … allows speech.
The pharynx connects the air channel to the alimentary canal. This design allows
disposal of both excess moisture in the air channel, and the debris in the lung
system that is filtered from the air by bronchial mucus. The mucus is moved up out
of the lungs by cilia and is then swallowed. The design allows the creation of air
pressure bursts, a response called coughing or sneezing that is necessary to remove
irritants from the throat and nose. This system is critical to force out objects,
such as food which can occasionally get stuck, in the area of the food tube above
the epiglottis or in the back of the mouth.
The pharynx structure permits the mouth and nose to alternate as breathing ports—a
feature that is critical whenever the nose is plugged, as when suffering from a
cold, or the mouth is blocked, such as when it contains food. The nostrils are used
when there is a need for breathing normal quantities of warmed, humidified, filtered
air, and the oral cavity allows rapid entry of much larger quantities of air when
needed. The tongue, teeth, palate, mandible and cheeks are all necessary for manipulating
food, but they are also required for speech.5
These structures, called articulators, have critical functions in the formation
of vowel sounds.6 The two-tube
design would require two separate mouths, tongues, teeth and other structures, duplicating
many of the same structures, using one set for eating and the other set for speaking.
The pharynx design allows both simultaneous eating and breathing with greater efficiency
and less body bulk than if we had two separate unconnected channels. Importantly,
one cannot breathe and swallow at the same time, effectively separating the two
systems. The two separate systems also function exceptionally well because unconscious
reflexes, in the absence of disease, allows them to function without concern or
worry for most of our life. Critics argue, without empirical evidence, that completely
separate tube systems, one for respiration and another for the alimentary tract,
would be a superior design. This design, though, some argue based on knowledge of
anatomy and logic, would require a far more complex tube and networking system,
resulting in a greater likelihood for errors and casualties. Two systems would have
to be coordinated so they could operate separately.
Another problem with the [evolutionists’ hypothetical] design is the more
bodily openings there are, the more difficult it is to protect the body from pathogens.
Another problem with this design is the more body openings there are, the more difficult
it is to protect the body from pathogens. By using three openings instead of the
present one, the likelihood of infections would also increase significantly, and
pathogen protection would likewise need to be increased. Given how many pathogens
we take into the oral cavity, two oral cavities would cause more problems with infections.
Another problem is that the sense of taste is intimately involved in our sense of
smell. For this reason, the olfactory sense used in both eating and digestion is
also part of the respiratory system that allows us to ‘taste’ our food.
Otherwise, food would be tasteless, such as occurs when we have a heavy cold. Separate
systems would require a totally different design, which would be impractical.
Humans, unlike apes, have a ‘descended larynx’ (meaning it is located
much farther down the trachea toward the lungs than it is for all other primates).
In humans, the larynx actually sinks lower as the baby grows until, in
adults, it is located at the junction of the food tube and larynx (windpipe) directly
below the base of the tongue. Rice adds that the ‘long larynx’ in humans
is what allows humans to choke but also allows humans to use language.7 Furthermore, so far as is known, this design feature
exists in one primate only—Homo sapiens.8 This design allows speech in humans—the only
life form on Earth that has complex language—which is a major reason why Darwinists
argue that a descended larynx must have evolved first, and only later was speech
able to evolve.8 This design feature also makes gulping large amounts
of air very easy, a very useful trait for under water swimming.
Many critics of the design argument commit the logical fallacy of ‘special
pleading’ by calling the human pharynx design ‘the height of stupidity’
when discussing creation, but view the pharynx as a masterpiece of engineering when
they attribute its design to evolution. This illogical reasoning is unfortunately
common in debates on origins. The fact is, pharynx design serves several functions
efficiently and effectively.
The problem of abuse and disease
When food or water enters the wrong tube (the trachea) it is not because the system
is poorly designed, but it occasionally malfunctions because of abuse, such as eating
while under the influence of alcohol or someone applying first aid incorrectly.
People do not die because of a poorly designed pharynx, but rather because of its
abuse or disease.
Many critics of design commit the logical fallacy of ‘special pleading’
by calling the human pharynx design ‘the height of stupidity’ when discussing
creation, but view the pharynx as a masterpiece of engineering when they attribute
its design to evolution.
In support of their claim, poor design advocates cite statistics on choking. Humans
swallow about 1,000 times a day or 27,375,000 times in an average lifespan. Given
this fact, life threatening choking events is actually a comparatively very rare
event when compared with the number of swallowing events during a lifetime. It is
most common in very young children, often caused by swallowing small toys, hard
candy or gum—all things that small children should not have.9 The most common choking problem is with infants
under six-months old. Over half is non-food related and most is due to lack of proper
parental supervision. The next largest problem is in the elderly, often caused by
disease such as strokes, Parkinson’s, Alzheimer’s, Myasthenia Gravis,
Amyotrophic Lateral Sclerosis, Cerebral Palsy, Multiple Sclerosis or some type of
dysphagia (the medical term for difficulty in swallowing which could be caused by
many factors such as nerve damage to the swallowing reflex). A final group for which
choking is a problem is the developmentally handicapped.
For healthy adults, the most common problem is eating too fast, trying to swallow
too large a portion of food, talking or laughing while eating. All of these problems
the Heimlich manoeuvre10
can usually solve if properly applied. Irresponsible behaviour involving excess
alcohol and inebriation is a major factor involved in choking, as is eating too
fast and not properly chewing one’s food. Improperly chewing certain foods,
including especially steak, is often implicated in chocking. Eating too fast and
not cutting up one’s food into small enough pieces tend to go together. Another
serious problem is the aspiration of food into the lungs. This can cause pneumonia
and can be lethal. This comparatively rare event usually occurs in stroke victims
or others who have nervous system damage that interferes with proper functioning
of the complex swallowing system.
In the vast majority of cases problems only arise with a misuse or degeneration
of the system.
The system is so effective that multi-millions of people have consumed three meals
a day for a lifetime without problems. Swallowing causes the pharynx to stimulate
several very complex reflex responses. The first shuts off the passage into the
nose by raising the vellum, and the next closes the opening of the trachea with
a flap called the epiglottis, and another that pushes the food down into the top
of the esophagus. The human soft palate elevates in order to close off the nasopharynx,
a very different design than that used in all primates.
In the vast majority of cases problems only arise with a misuse or degeneration
in the system. This cannot be used as evidence of bad design because good original
design takes into account neither unwise usage of the design nor subsequent degeneration
of the system. Rather, this is expected within the biblical model, as the Fall has
produced degeneration and was caused by (and produced more) unwise choices!
Conclusions
When the oral cavity’s many functions are carefully considered and compared
to other possible designs, it shows that the ‘bad design’ claim is invalid.
There are at least a dozen important reasons for its existing design. The only way
to scientifically prove a system is better is to do a scientific comparison of two
groups, one group that uses each system. This experiment will never be done as it
would require major surgery and likely would create serious health problems. Evolutionists
trying to defend their claims could at least explore the many changes required to
produce two separate functional systems, something that no one has done. Darwinists
who criticize the existing system have not proposed the details or any evidence
of a functional better design.
Acknowledgements
I wish to thank Frank Moore, M.D., Clifford Lillo, MA and Jody Allen, RN, for their
helpful suggestions on an earlier draft of this article.
Related articles
Further reading
Related resources
References
- Letter quoted in Howe, G., Correspondence series, Students
for Origins Research 4(1):3, 1981. Return to
text.
- Atrain, S., Unintelligent Design; in: Intelligent Thought,
Brockman, J. (Ed.), Vantage, New York, chapter 9, pp. 129–130, 2006.
Return to text.
- Skybreak, A., The Science of Evolution and The Myth of
Creationism: Knowing What’s Real and Why It Matters, Insight Press, Chicago,
IL, p. 109, 2006. Return to text.
- Walter, C., Thumbs, Toes, and Tears and Other Traits that
Make Us Human, Walker and Company, New York, 2006. Return to
text.
- Laitman, J., The anatomy of human speech, Natural History
8:20–27, 1984. Return to text.
- Gordon-Brannan, M.E. and Weiss, C.E., Clinical Management
of Articulatory and Phonologic Disorders, Lippincott Williams and Wilkins,
Philadelphia, PA, 2007. Return to text.
- Rice, S., Encyclopedia of Evolution, Facts on File,
New York, p. 232, 2007. Return to text.
- Morgan, E., The Scars of Evolution: What Our Bodies Tell
Us about Evolution, Oxford University Press, New York, 1994.
Return to text.
- Baker, S.P., O’Neill, B., Ginsburg, M.J. and Li, G.,
The Injury Fact Book, 2nd ed., Oxford University Press, New York, 1992.
Return to text.
- The Heimlich manoeuvre is performed by a person standing
behind the person choking and exerting upward pressure on the diaphragm of the patient
to compress the lungs and force air out through the trachea, hopefully dislodging
the choking object in the process. Return to text.
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