Irreducible Complexity

Professor of biochemistry at Lehigh University, Dr. Michael Behe wrote “Darwin’s Black Box” in 1996. A seminal work in support of Intelligent Design, Behe’s book introduced the term irreducible complexity to the debate between proponents of Darwinian evolution and its skeptics.

Simply put, Behe argued that many systems found in nature are irreducibly complex. Meaning that if we take away one or more of their parts, they have zero function. Darwinian proponents on the other hand, believe that nature was built successively, one step at a time. Therefore, all existing organism and their body parts had functions before they attained their current structure. For example, before our legs were fully developed, according to Darwinian evolutionists, they were less effective but still functional as moveable appendages. Nature selected for slight modification after slight modification improving nature’s systems. But if Behe is right, it appears that many (if not most) systems in nature require a coming together of several parts before any function is allowed at all. This contradicts the evolutionary view of “one step at a time” evolutionary staircase.

irreducible complexity 2

An oft used example of irreducible complexity is the mousetrap. As a basic structure, the mousetrap requires all of its parts before it has any function at all. Remove the spring, and the trap’s “hammer” won’t budge and mice will eat all the cheese they want. Remove the wood base and none of the parts will be anchored to anything and nothing will happen. No matter which part you remove, you will lose any and all function. Likewise, things like the spinning tail that germs use to move around (i.e.: bacterial flagellum) were proposed as examples of organic machines that also require all of their parts in order for any function to occur.

irreducible complexity 3

Dr. Behe compares the bacterial flagellum to an outboard motor. Like the boat engine, the flagellum requires parts that highly resemble a mechanical design used for all propellers. This organic system is designed to allow bacteria to propel themselves through a liquid medium. It is made up of dozens of proteins and is fitted together in a maximally efficient and simple motor system that functions to allow the single celled organisms to move.

In 2004 the Dover School Board in Pennsylvania wanted to allow their high school biology students to be aware of criticism to Darwinian evolution such as irreducible complexity. Here is their statement in full:

“The Pennsylvania Academic Standards require students to learn about Darwin’s theory of evolution and eventually to take a standardized test of which evolution is a part.

“Because Darwin’s theory is a theory, it continues to be tested as new evidence is discovered. The theory is not a fact. Gaps in the theory exist for which there is no evidence. A theory is defined as a well-tested explanation that unifies a broad range of observations.

“Intelligent design is an explanation of the origin of life that differs from Darwin’s view. The reference book, ‘Of Pandas and People,’ is available in the library along with other resources for students who might be interested in gaining an understanding of what intelligent design actually involves.

“With respect to any theory, students are encouraged to keep an open mind. The school leaves the discussion of the origins of life to individual students and their families. As a standards-driven district, class instruction focuses upon preparing students to achieve proficiency on standards-based assessments.”

To those of us who feel free to be skeptical of natural Darwinian evolution, the above statement appears very demure. But it caused a major firestorm and lead to a high profile court case. On December 20, 2005 the judge presiding over the case rendered a decision which labelled the Dover statement to be unconstitutional because it was religious indoctrination masquerading as science. And therefore, said the judge, it was a violation of the separation of Church & State.

During the trial, examples of irreducible complexity such as the bacterial flagellum were front and centre. Brown University biology professor Dr. Kenneth Miller claimed that Dr. Michael Behe’s notion of the flagellum being irreducibly complex was false because other bacteria had been found to have a similar structure that lacked about 30 proteins compared to the flagellum but were still functioning as Type 1, 2, 3 and 4 Secretion Systems. These are used to move proteins and other chemicals into and out of bacteria. The Type 3 Secretion System (T3SS) is essentially a syringe used by bacteria to inject other organisms:

irreducible complexity 4

Behe also was allowed to testify in front of the court and he, as well as other proponent of Intelligent Design (who spoke during and after the trial in books, blogs and other mediums), answered Dr. Miller and his Type 3 Secretion System argument.

  1. All of the 4 secretion systems themselves had irreducibly complex parts. You can’t have an import/export unit without a functioning gate, for example.
  2. The genetic code and the corresponding proteins that make up the T3SS are only 25% the same as the genes and only 20% of the same proteins used to build the flagellum’s spinning propeller (discovered by Pallen et al in 2005). Therefore these two similar structures are not simply a few genetic blips away from each other (i.e.: the syringe of the T3SS did not simply began spinning and voila, flagellum!).
  3. All of the parts of the 4 secretion systems as well as the bacterial flagellum are built from genetic information. As a result, in order to invoke evolution as a reason for the transition from one design to the next, the obstacle of attributing new, innovative genetic information creation without using an purposeful, intelligent mechanism still stood.
  4. The parts used in the bacterial flagellum that did not exist in Types 1 through 4 Secretion Systems were perfectly fitted for the flagellum and did not exist, floating around the innards of bacteria, waiting to be co-opted to improve the Secretion System. Therefore, the innovation and presence of a moving propeller appears to be specifically designed.
  5. By looking at the depth and amount of mutations existing in the genetic code region in bacteria that code for both the bacterial flagellum and the Type 3 Secretion Systems, it was found that the bacterial flagellum was indeed older than the Type 3 Secretion System. Therefore, if anything, the Secretion System was a de-volution from the flagellum. Or simply another similarly designed, irreducibly complex structure that served a specific purpose in single celled organisms such as bacteria.
  6. Almost all bacteria contain the genetic code for the flagellum. Only some have the T3SS genes. All bacteria with T3SS genes also have the flagellum genes. Further, the type of bacteria that contain the T3SS are specialized to attacking eukaryotic cells. Eukaryotes arrived a billion years after prokaryotes (i.e.: bacteria and other single celled organisms). These facts seem to unequivocally place the T3SS genes as arriving much later than the flagellum genes. Making it impossible for the flagellum to be simply an evolutionary improvement on the T3SS.

Group of the E coli Bacteries on color background

There are many examples of irreducibly complex systems throughout nature. As well as many examples of complex organisms that require an irreducibly complex amalgamation of parts (e.g.: circulatory systems that function with appropriate skeletal and digestive systems, etc) fitted perfectly together and seemingly unable to suffer being reduced bit by bit. On scales even smaller than the flagellum are things such as kinesin motor proteins. These tiny nanobots made up of proteins “walk” along cytoskeletal structures and are used for multiple purposes inside cells. From moving the little arms of cells or tissues (i.e.: cilia) to helping cells divide during mitosis to transporting macro molecules around, kinesin and other motor proteins are little workhorses inside cells.

When we step back and see the “big picture” of how the nano world of biology is built. We not only see a world filled with irreducibly complex structures but a world riddled with micro machinery and interlocking systems on chemical, cellular and organic levels. Then we realize that this whole world is built by other nano-machines that themselves are using the encoded information of the genetic library in order to do so. One has to wonder how a purposeless, blind and completely rock-dumb world of inorganic atoms could have assembled this enriched world of engineering beauty.

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