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What is the evidence for or against the notion that species (including humans) have been individually designed?
David H. Bailey
10 November 2018 (c) 2018
One of the key tenets of both creationism and intelligent design is that whereas minor variations are possible among different members of a given "kind," such variations do not extend beyond the boundary of the "kind." (The term "kind" as used by these communities is not clearly defined, but it appears to mean individual species.) Instead, each individual "kind" has been separately created or designed in meticulous detail by an intelligent Being. The intelligent design community, in particular, points to the many intricate, well-adapted features as evidence of this Designer [Behe1996]. The intelligent design writers typically do not directly identify this Designer as the Judeo-Christian God, although this is implicit in other writings.
Difficulties with the design hypothesis
Both the intelligent design community and some of its detractors point to the early 19th century scholar William Paley as the intellectual pioneer of this line of thought. However, recent research by Adam Shapiro draws this conclusion into question. Instead, Paley's empirically-argued theology saw God as operating in accord with natural law, not by contravening natural law [Shapiro2009].
Scientists, including numerous prominent scientists who are also devout religious believers, counter such arguments by noting that Darwin's discovery of evolution has provided a natural framework to explain apparent design. With regards to the examples of apparent design that have been promoted in creationist and intelligent design literature, scientists note that in virtually all cases these are well covered by published research showing how these features could and likely did arise (see
There are also some theological difficulties with the above concept of design. To begin with, the design hypothesis fails to explain the huge amount of pain, violence and suffering that is experienced in the natural world. Indeed, one of the theological advantages of the evolutionary model is that it doesn't cast the responsibility for all of these problems on God. This is discussed in additional detail at
Examples of deficiencies in nature
More importantly, the design hypothesis founders on the numerous known examples in the biological world, including numerous examples in the human body, of features that are clearly deficient -- they could have been "designed" more rationally, but were not. At the very least, "design" must be seen in only a high-level sense of permitting the forces of natural evolution to proceed. Here are just a few of the many striking examples scientists have found that present severe difficulties for the notion that biological systems have been meticulously designed:
Numerous other examples could be cited. Did God "design" humans with these specific deficiencies and vulnerabilities, or is it our religious duty to use the scientific method to understand these problems, and, where possible, to counter their effects and mitigate the suffering?
- Nearly all species that have ever arisen on this planet have become extinct. It seems rather strange to suggest that God "designed" individual species by the millions, only to see virtually all of them ultimately fall into oblivion. For example, scientists have found 22 distinct species of elephants that arose and became extinct during the past six million years. Why did it take so many tries to "design" modern elephants? [Miller1999, pg. 97]. See
Fossils for a family tree of the numerous known elephant species.
- Vitamin C (ascorbic acid) is required for a wide range of essential metabolic reactions. Scurvy, that scourge of British seamen, Mormon pioneers crossing the Great Plains, and millions in poor regions worldwide even today, results when humans don't get enough Vitamin C. Most animals, including nearly all mammals, generate their own vitamin C, but while humans have the same overall biochemical machinery, it doesn't work because mutations have inactivated at least one key step [Coyne2005, pg. 68; Fairbanks2007, pg. 53-54; Miller2008, pg. 97-98]. What's more, very similar mutations are found in the other great apes, such as orangutans, chimpanzees and gorillas, but not in other more distantly related primates, such as lemurs. Evidently these mutations occurred after ancient primate ancestors adopted a diet rich in fruits and vegetables, so that when some individuals lost the ability to generate their own Vitamin C due to mutations, it was not deleterious to their survival, and the trait was passed on to posterity. But it would be very strange to insist that God "designed" humans with such a glaring "computer program bug" in their DNA. And it would be stranger still to insist that God copied this same computer program bug into the genomes of some other species [Miller2008, pg. 97-98].
- The laryngeal nerve is a branch of one of the cranial nerves, the nerves that lead directly from the brain rather than from the spinal cord. On each side of the neck, one of the branches of the laryngeal nerve goes directly to the larynx, following a direct route. The other goes down into the chest, around one of the main arteries near the heart, and then back up the neck to the larynx. In humans, this strange "detour" is only a foot or two long, but in an adult giraffe, the detour is 15 feet long! [Coyne2009, pg. 72; Dawkins2009, pg. 356-364]. This detour makes perfect sense from evolutionary history (from the stretching of the neck and the modification of gills in ancient ancestors), but it makes no sense at all from a "design" hypothesis.
- Thirty percent of the roughly 1000 human genes associated with the sense of smell are inoperable due to accumulated mutations [Shubin2008, pg. 146].
- In the eyes of humans and other mammals, the optic nerves emerge from the front of the retina, and then travel to the back, resulting in a blind spot. By contrast, the eyes of cephalopods (including the octopus, squid, cuttlefish and nautilus) are designed more logically with nerve connections on the back of the retina [Miller2008, pg. 150-151; Fairbanks2012, pg. 34-37].
- The vas deferens carries sperm and is thus essential for reproduction. But in humans and other mammals, the vas deferens takes a strange detour up and over the ureter, the tube that carries urine from the kidneys to the bladder [Dawkins2009, pg. 364-365]. Again, this detour makes perfect sense from evolutionary history, but no one would ever "design" the system this way. Another questionable feature of the male reproductive system is the prostate gland. In a substantial fraction of the human male population, the prostate continues to grow through middle age, squeezing the urethra, making urination difficult or even painful, and, in some cases, resulting in kidney damage or even death. Evidently this was not a problem for most of evolutionary history, when relatively few men lived past 50 years, but it is a significant health problem today for men worldwide [Coyne2009, pg. 84].
- Many persons suffer from back ailments, due to a skeletal design that clearly has been adapted from four-footed ancestors [Miller1999, pg. 101; Dawkins2009, pg. 369]. Another byproduct of our adaptation from four-footed ancestors, which causes considerable misery for those prone to sinus headaches, is that human sinuses drain through a hole at the top instead of at the bottom [Dawkins2009, pg. 370].
- Humans are subject to over 500 genetic disorders, and doubtless many more will be identified in the coming years with the explosion of genome sequence data. Cystic fibrosis, a debilitating and often lethal disorder that affects not only the lungs, but also the pancreas, liver and kidneys, results from mutations in the "CFTR" gene in chromosome seven. Similarly, Huntington's disease, a fatal neurological disorder resulting in uncontrollable body movements and dementia, has been narrowed down to mutations at a specific spot on chromosome four [Avise2010, pg. 52-55].
The notion of God as a high-level Designer of the natural world, a Being who created within the foundations of its natural laws and processes the capability for evolution in general, and evolution leading to intelligent life in particular, is a generally reasonable theological proposition (although some scholars disagree). But the stronger hypothesis promoted by creationists and intelligent design writers, namely that each individual species or "kind" was meticulously and individually "designed," is countered by large amounts of widely available scientific evidence and is almost universally discredited among knowledgeable researchers in the scientific community.
Indeed, in the light of the many genetic defects that have been observed in nature in general and in humans in particular, the notion that God specifically "designed" species, including human beings, with these defects, and, further, copied many of these defects into the genomes of other related species, is downright blasphemous. It is much more reasonable, from both a scientific point of view and a theological point of view, to simply acknowledge the evolutionary explanation, and to not try to insist that scriptures or theological reasoning alone can dictate technical details of the origin and rise of living species on this planet.