Burgess: Claims of “Poor Design” in Skeletal Joints Are Based on Critics’ Lack of Training in Engineering
As an engineering professor at Bristol University and Cambridge, Stuart Burgess has researched biomechanics for nearly thirty years. He is one of the leading engineers in the UK. Earlier this year, he presented a talk at the Westminster Conference on Science and Faith titled, “Why Human Skeletal Joints Are Masterpieces of Human Engineering: And a Rebuttal to the ‘Bad Design’ Arguments.” He demonstrated that human skeletal joints are marvels of engineering and optimally designed. In particular, he refuted claims by biologist Nathan Lents, in his book Human Errors: A Panorama of Our Glitches, from Pointless Bones to Broken Genes, that the wrist and ankle contain useless bones.
The Abuse of Science
Burgess’s lecture confronts one of the most common abuses of science aimed at suppressing the evidence for design in biology. Atheists such as Lents have grossly misrepresented the scientific evidence related to biological systems to claim that life often displays clumsy and incompetent engineering. Most of the examples of allegedly poor design listed by Lents, or in other books such as The Language of God, were known to be false when the books were written or have since been discredited. Such disinformation resulting from sloppy scholarship has derailed the faith of religious adherents and robbed atheists and agnostics of the opportunity to pursue belief in a Creator.
In relation to wrists and ankles, Lents makes the following assertions in his book:
- “The small area that is just the wrist itself has eight fully formed and distinct bones tucked in there like a pile of rocks — which is about how useful they are to anyone.” (p. 28)
- “We have examples of superbly designed joints in our bodies; the shoulder and hip joints come to mind. Not the wrist, though. No sane engineer would design a joint with so many individual moving parts. It clutters up the space and restricts the range of motion.” (p. 28)
- “The human ankle suffers from the same clutter of bones that we find in the wrist. The ankle contains seven bones, most of them pointless.” (p. 29)
Yet none of these claims has any basis.
The Optimality of Skeletal Joints
Dr. Burgess demonstrated how Lents’s assertion that the wrist and foot joints are poorly designed results from Lents’s lack of training in engineering. He did not recognize that living systems must meet multiple competing constraints. Burgess analyzed the joints’ different motions and functions. He then demonstrated how the wrists and ankles are exquisitely designed to optimally achieve a diversity of functions in a wide variety of environments.
As one example, Lents failed to understand the engineering principles behind the four bones adjacent to the toe bones. He claimed that a better design would have been to replace these bones with a single composite bone. The key error is that the multiple bones provide far greater load bearing strength.
In a previous lecture, Burgess also addressed false claims about allegedly poor design in the human knee joint, while in the technical literature he detailed the optimality of the knee (here, here). Many have argued that the ease with which the knee’s anterior cruciate ligament (ACL) tears reflects poor design resulting from humans’ evolutionary past. This conclusion fails to recognize a key design principle: engineers often deliberately construct the least critical components in a complex system to fail first.
The bumper of a car, for example, is designed to crumple long before the passenger compartment since the former is far more expendable. Similarly, a person can still walk with a torn ACL, but serious trauma to other knee tissues and bones could permanently cripple the individual. The initial failure of the ACL could prevent much more severe damage. In addition, the rate at which ACLs tear is lower than the rate at which bones such as the femur fracture (here, here). Claims about the ACL’s flimsy design are clearly misguided.
The Central Lesson
Burgess could have spoken for many more hours about false claims of poor design in such structures as the wiring of the retina, the human appendix, and wisdom teeth. He could have provided countless examples of biology demonstrating the pinnacle of engineering brilliance.
Yet the two examples he presented were sufficient to drive home a clear lesson. Evolutionary assumptions consistently lead biologists to falsely claim that features in life reflect incompetent engineering, and those assumptions bias them to undervalue biological systems’ ingenuity and optimality. One hopes that the consistent track record of falsely identifying poor design will result in researchers’ applying greater caution in the future before questioning the wisdom of a feature in life that they do not initially fully understand.