Behe argues that the theory that irreducibly complex systems could not have been evolved can be falsified by an experiment where such systems are evolved.

Notably, Behe credits philosopher William Paley for the original concept, not von Bertalanffy, and suggests that his application of the concept to biological systems is entirely original.

Behe and others have suggested a number of biological features that they believe may be irreducibly complex.

They claim that Behe overestimated the significance of irreducible complexity because of his simple, linear view of biochemical reactions, resulting in his taking snapshots of selective features of biological systems, structures and processes, while ignoring the redundant complexity of the context in which those features are naturally embedded.

Behe states that elucidations of the evolutionary history of various biological features typically assume the existence of certain abilities as their starting point, such as Charles Darwin's example of a cluster of light-sensitive spots evolving into an eye via a series of intermediate steps.

In the following chapters, Behe discusses the apparent irreducible complexity of several biological systems, including the cilium, the bacterial flagellum, blood clotting, the immune system and intracellular gated and vesicular transport.

In the same trial, Behe eventually testified under oath that " There are no peer reviewed articles by anyone advocating for intelligent design supported by pertinent experiments or calculations which provide detailed rigorous accounts of how intelligent design of any biological system occurred ".

Although Behe acknowledged that the evolution of the larger anatomical features of the eye have been well-explained, he claimed that the complexity of the minute biochemical reactions required at a molecular level for light sensitivity still defies explanation.

The judge in the Dover trial wrote " By defining irreducible complexity in the way that he has, Professor Behe attempts to exclude the phenomenon of exaptation by definitional fiat, ignoring as he does so abundant evidence which refutes his argument.

Behe asserts that the absence of any one of these proteins causes the flagella to fail to function, and that the flagellum " engine " is irreducibly complex as if we try to reduce its complexity by positing an earlier and simpler stage of its evolutionary development, we get an organism which functions improperly.

Potentially viable evolutionary pathways have been proposed for allegedly irreducibly complex systems such as blood clotting, the immune system and the flagellum, which were the three examples Behe used.

For example, Kenneth Miller cites the lab work of Barry G. Hall on E. coli, which he asserts is evidence that " Behe is wrong.

Laurence A. Moran writes that by concentrating the attention of the opponent on the stated examples, which are carefully selected to be hard to explain, Behe constructs a Strawman

* " By defining irreducible complexity in the way that he has, Professor Behe attempts to exclude the phenomenon of exaptation by definitional fiat, ignoring as he does so abundant evidence which refutes his argument.

We will now consider the purportedly “ positive argument ” for design encompassed in the phrase used numerous times by Professors Behe and Minnich throughout their expert testimony, which is the “ purposeful arrangement of parts .” Professor Behe summarized the argument as follows: We infer design when we see parts that appear to be arranged for a purpose.

Intelligent design advocate Michael Behe proposed a development of Paley's watch analogy in which he argued in favour of intelligent design.

Behe is best known for his argument for irreducible complexity, which asserts that some biochemical structures are too complex to be adequately explained by known evolutionary mechanisms and are therefore more probably the result of intelligent design.

" Nagel does not accept Meyer's conclusions but he endorsed Meyer's approach, and argued in Mind and Cosmos that Meyer and other ID proponents, David Berlinski and Michael Behe, " do not deserve the scorn with which they are commonly met.

Intelligent design proponent Michael Behe contends that the system is an example of irreducible complexity and therefore could not have evolved, an argument which is rejected by scientists as logically and factually flawed.

Darwin's Black Box: The Biochemical Challenge to Evolution ( 1996, first edition ; 2006, second edition ) is a book written by Michael J. Behe and published by Free Press in which he presents his notion of irreducible complexity and claims that its presence in many biochemical systems indicates therefore that they must be the result of intelligent design rather than evolutionary processes.

In 1993, Behe had written a chapter on blood clotting in Of Pandas and People, presenting essentially the same arguments but without the name " irreducible complexity ", which he later presented in very similar terms in a chapter in Darwin's Black Box.

Behe begins by reminding the general reader of paradigm shifts in the history of science, in which the foundations and assumptions of theories are examined, sometimes resulting in the rejection of an entire theory.

Behe next introduces and defines the concept of irreducible complexity as a system with a series of parts in which the removal of any part causes the entire system to cease functioning, offering a springloaded-bar mousetrap as a familiar example.

Though Behe has avoided committing himself to the view that God intervenes directly in nature to create purportedly irreducibly complex structures, Darwin's Black Box briefly speculates that divine intervention might have caused the direct creation of a cell from which all of life evolved, supporting creationist views of miraculous acts of creation, but ironically echoing Darwin's stated " view of life, with its several powers, having been originally breathed into a few forms or into one ".

In 2005, while testifying for the defense in the Dover trial, Behe claimed under oath that the book had received a more thorough peer review than a scholarly article in a refereed journal, a claim which appears to conflict the facts of the book's peer review.

; Russell Doolittle: Doolittle, upon whom Behe based much of his discussion of blood clotting, described it as misrepresenting many important points and disingenuous, which also contributed to the original publisher turning down the book for publication.

For the 1993 edition, Michael Behe wrote a chapter on blood clotting, presenting arguments which he later presented in very similar terms as " irreducible complexity " in a chapter in his 1996 book Darwin's Black Box.

It may be that irreducible complexity does not actually exist in nature, and that the examples given by Behe and others are not in fact irreducibly complex, but can be explained in terms of simpler precursors.

While testifying at the Kitzmiller v. Dover Area School District trial Behe conceded that there are no peer-reviewed papers supporting his claims that complex molecular systems, like the bacterial flagellum, the blood-clotting cascade, and the immune system, were intelligently designed nor are there any peer-reviewed articles supporting his argument that certain complex molecular structures are " irreducibly complex.

Contrary to Professor Behe ’ s assertions with respect to these few biochemical systems among the myriad existing in nature, however, Dr. Miller presented evidence, based upon peer-reviewed studies, that they are not in fact irreducibly complex.

Behe claims that there are instances of irreducible complexity in the natural world and that parts of the world must have been designed.

Among them are leaders of the intelligent design movement and fellows of the Discovery Institute's Center for Science and Culture, the hub of that movement, including Dembski, Michael Behe, Jonathan Wells, William Lane Craig, and Henry F. Schaefer.

Behe claims the underlying complexity and biochemical mechanisms of the systems are vastly under-appreciated, and identifies other, similar systems.

Behe's thesis that irreducible structures are created in " one fell swoop " is opposed by other biochemists, including many who are devout Christians, and has, it is claimed by some, no support from the fossil record-something Behe would dispute.

Biochemistry professor Michael Behe, the originator of the term irreducible complexity, defines an irreducibly complex system as one " composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning ".

Behe has been accused of using an " argument by lack of imagination ", and Behe himself acknowledges that a failure of current science to explain how an " irreducibly complex " organism did or could evolve does not automatically prove the impossibility of such an evolution.

Behe identifies one of the primary counter-arguments of irreducible complexity, gradual adaptation — that certain systems may have been co-opted from an original, unrelated role to assume a new function as an irreducibly complex system.

A review on the pro-evolution website talk. origins, described the book as "... an exposition of the Frontiers of Ignorance " and that within it systems were labeled " irreducibly complex " if Behe was not able to envision a simpler system that still worked.

Minnich, Behe, and Paley reach the same conclusion, that complex organisms must have been designed using the same reasoning, except that Professors Behe and Minnich refuse to identify the designer, whereas Paley inferred from the presence of design that it was God.

" Behe specifically explained that the " current definition puts the focus on removing a part from an already functioning system ", but the " difficult task facing Darwinian evolution, however, would not be to remove parts from sophisticated pre-existing systems ; it would be to bring together components to make a new system in the first place ".

Mainstream critics, however, argue that irreducible complexity, as defined by Behe, can be generated by known evolutionary mechanisms.

For example, one of the clotting factors that Behe listed as a part of the clotting cascade was later found to be absent in whales, demonstrating that it is not essential for a clotting system.

* " Professor Behe admitted in " Reply to My Critics " that there was a defect in his view of irreducible complexity because, while it purports to be a challenge to natural selection, it does not actually address " the task facing natural selection.

Expert testimony revealed that this inductive argument is not scientific and as admitted by Professor Behe, can never be ruled out.

Michael Behe, in his book Darwin's Black Box, suggested the designer might be a time traveling cell biologist.