Biological Information and Irreducible Complexity
what the latest biochemical discoveries suggest
about the validity of Darwinian evolution

Ever since 1859, Darwinian evolution has been the paradigm by which biologists have carried out their work. So certain have most biologists become of this theory that any opposition to it is often met with disdain. Simply stated, Darwinian evolution states that life somehow emerged from natural causes and then developed in small, incremental steps by way of mutations favored by natural selection. So foundational is this commitment to slight modifications that Darwin himself said "if it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down" (Darwin, Origin of Species, 154).

It is precisely this realization that has caused many scientists to pause as they question the validity of Darwin's theory. Over the last forty years or so, vast amounts of information have been uncovered in the field of biochemistry that were previously unknown. As a consequence of years of investigation and reflection, many scientists and other scholars are beginning to suggest that this new hurdle of biochemistry is simply too high for Darwin to jump over.

These scientists and other scholars have joined together in what is unofficially known as the Intelligent Design movement. This "movement" began in the mid-eighties with two powerful critiques of Darwinism -- The Mystery of Life's Origin by Charles Thaxton, Walter Bradley and Roger Olson (1984); and Evolution: A Theory in Crisis by Michael Denton (1986). Then Phillip Johnson (UC Berkeley Professor of Law) came out with several eye-opening works which expose the naturalistic philosophy which has generally driven modern evolutionary theory. These books include Darwin on Trial (1991), Reason in the Balance (1995), and Defeating Darwinism by Opening Minds (1997). After several years of critique, alternatives to evolutionary theory began to emerge. These alternatives can be found in books such as Of Pandas and People by Dean Kenyon and Percival Davis, and Creation Hypothesis edited by J. P. Moreland.

The flood gates opened, however, with Michael Behe's book Darwin's Black Box (1996). In this book, Behe (noted Professor of Biochemistry) explains that, although biology has progressed tremendously under the Darwinian paradigm, we have only recently begun to understand how biological processes actually function. In Darwin's day, the foundational building blocks of biology were "black boxes," that is, they were closed to our observation. But now, through the development of the microscope, these black boxes have been opened. We now have the ability to peer into this biochemical world that Darwin was blind to (through no fault of his own). Behe, with hundreds of others, suggests that Darwin's model is not capable of bearing the load of biochemical evidence that has just been uncovered in the last forty years.

It is important to note that "Darwinism" refers to a specific brand of evolution. Those involved in the Intelligent Design movement are not opposed to evolution as such. In fact, everyone believes in evolution. The question is, what kind of evolution do you believe in? Evolution simply means change. In the biological realm, it simply means change in species. No one denies the reality of this. This kind of evolution is referred to as "micro-evolution." The term "macro-evolution" means something different. While the former refers to slight changes after the appearance of life, the latter refers to the appearance of life by means of slight changes. Darwinian evolution is the latter brand of evolution -- the emergence of life through a long series of minute changes.

It is also important to note that Darwinian evolution is naturalistic evolution. Some today would suggest that life emerged by means of evolution, but only by God intervening at key points along the way, such as the beginning of human life and the beginning of life itself. This notion, however, is foreign to Darwinian evolution (which is the pervading view in the academic world). Darwinism states that life emerged and developed incrementally strictly by natural causes.

In some ways, this paper is asking a question that Darwin was not really able to address. In his book Origin of Species, Darwin attempted to deal with the issue of how life developed once it got here, but was not able to deal with the issue of how it got here because of where science was in his day. By observing the data from the latest biochemical discoveries, however, I wish to ask the question, does life have a natural cause or an intelligent cause?

Before we examine this evidence, we must ask if this is indeed a legitimate question for science. Some would suggest that considering the possibility of an intelligent cause puts one outside the realm of science. This, however, reveals an unwarranted philosophical commitment. Any time someone asks the question "how did this happen?" two possibilities must be considered -- either it happened through natural processes or it happened through the actions of an intelligent agent. In fact, the question of whether an event was caused by nature or by intelligence is quite often asked in other historical sciences such as forensic science, cryptography and archeology. To limit one's options is to exercise poor investigative techniques and does not allow the evidence itself to guide the investigation.

A major reason why many scientists will not entertain the possibility of an intelligent cause when it comes to the origin of life is because of a fear of what is known as "the God of the gaps." "God of the gaps" refers to a problem found throughout history in which someone will attribute a certain event to the activity of God (because there is no known evidence for a natural cause) only to find out later that there actually was a natural cause. The resulting feeling is that God was not needed after all. After enough of these mistakes are made, God is effectively squeezed out of the picture altogether.

Those involved in the Intelligent Design movement, however, are not making the same "God of the gaps" fallacy. They are not claiming that life has an intelligent cause because of a lack of evidence for a natural cause. Rather, they are claiming that life has an intelligent cause because of the existence of strong empirical evidence that actually points to that conclusion. It is the existence of this biochemical evidence that has led many to believe that it is no longer reasonable to suggest that life had a natural cause.

The first great piece of evidence that suggests that life had an intelligent cause is the recent discovery of what Michael Behe calls "irreducible complexity" within biology. By irreducible complexity, Behe means "a single system 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, Darwin's Black Box, 39).

Behe illustrates this notion of irreducible complexity by referring to a mouse trap. A mouse trap consists of several parts: a flat wooden platform to act as a base; a metal base, which does the actual job of catching the mouse; a spring with extended ends to press against the platform and the hammer when the trap is charged; a sensitive catch that releases when slight pressure is applied; and a metal bar that connects to the catch and holds the hammer back when the trap is charged; (in addition to assorted staples to hold the system together). If one of these pieces is missing or defective, the mouse trap will not work.

While Darwin would suggest that life arose by means of small changes, Behe's example illustrates that since many biological systems are irreducibly complex systems, it is not feasible that they could have developed bit by bit by natural selection. Now, no one denies the existence of natural selection, but the difficulty is to see how natural selection could produce an irreducibly complex system piece by piece. The reason is because an irreducibly complex system will not function until all of the pieces are in place, and a non-functioning system is not beneficial and would not be favored by natural selection. Referring back to the mouse trap, Behe says the following: "You can't start with a platform, catch a few mice, add a spring, catch a few more mice, add a hammer, catch a few more mice, and so on: The whole system has to be put together at once or the mice get away" (Behe, Darwin's Black Box, 111).

Perhaps the most well-known example of irreducible complexity is the structure of the human eye. The human eye has been compared by many to a modern camera. The parts are quite similar and, like the camera, most pieces are necessary for the eye to function. In his book, The Blind Watchmaker, Richard Dawkins says that the human eye must have been produced by natural processes because it is here. This prematurely eliminates the option of intelligent causation from the discussion, and eliminating an option before one considers the evidence is simply not good science.

When Darwin realized the difficulty the human eye posed to his theory, rather than explaining the process by which the eye evolved, he simply pointed to the various eyes of modern animals and suggested that the evolution of the human eye must have involved similar organs as intermediates. There are two major problems with this approach. First, just because one can imagine something happening does not necessarily mean that it can happen, and it certainly doesn't mean that it did happen. This kind of reasoning resembles bed-time stories more than investigative science. But this is precisely the logical path that Darwin takes. The second problem with this approach is the total disregard for the problem of irreducible complexity. How is it that an eye containing interdependent parts (thus, all parts are required for the eye to be useful) could have evolved from an eye containing fewer parts?

The reason Darwin makes this mistake is because he fails to distinguish between a physical precursor and a conceptual precursor. A conceptual precursor is a simpler system that serves a similar function as the more complex system. A physical precursor is a simpler system from which the more complex system came. With reference to the eye, Darwin would like to suggest that since there are conceptual precursors to the human eye, there must also be similar physical precursors to the human eye. This is like saying that since a glue trap is a conceptual precursor to a mouse trap (simpler system to catch mice) it is also a physical precursor. But I have yet to see someone make a mouse trap out of a glue trap. Likewise, although the bicycle is a conceptual precursor to the motorcycle, no motorcycle in history (not even the first) was made simply by modifying a bicycle in a stepwise fashion. But this is exactly what Darwin suggests concerning the human eye. Darwin stumbles in his logic when he suggests that a conceptual precursor suggests a physical precursor.

Another example of irreducible complexity is the bacterial flagellum discovered in 1973. The flagellum is a long, hairlike filament embedded in the cell membrane. The external filament consists of a single type of protein, called "flagellin." The flagellin filament acts as a paddle, pushing against the liquid during swimming. This filament is connected to the rotor drive by a bulge called "hook protein." A "motor" turns the filament in a rotary fashion, propelling the bacterium through the liquid. With its rotor, rod, studs and rings, many have made the observation that the bacterial flagellum resembles something assembled by Ford, Crystler or General Motors. It even uses acid for fuel. As with the motors within the cars we drive, the "motor" in this small bacterium needs all of its many parts to operate. In reference to these facts, Behe makes the following observation: "Even though we are told that all biology must be seen through the lens of evolution, no scientist has ever published a model to account for the gradual evolution of this extraordinary molecular machine" (Behe, Darwin's Black Box, 72).

A third example of irreducible complexity is the foundation of biological life itself -- the cell. Ernst Haeckel characterized the thinking of the biological world of his day as he suggested that the cell was but a "homogeneous globule of protoplasm." Through the advancement of biological research, however, we now know that eukaryotic cells (which include the cells of all organisms except bacteria) have many different compartments in which different tasks are performed. Without getting into the details of the structure of the cell, it will suffice to say that these compartments are interrelated and necessary for the functioning of the cell. There are quite a number of these compartments, and they seem to function similarly to a delivery system within a large corporation. In cells, although some compartments make some materials for themselves, the great majority of proteins are centrally made and are then shipped to other compartments. Papers dealing with how such a vesicle transport system came about suggest that they evolved from preexisting bacterial transport systems that already had all the components that modern cells have. This, however, only begs the question. The question of how an original transport system could arise in the first place still remains (Behe, Darwin's Black Box, 115).

The human eye, the bacterial flagellum and the cell are but among the many examples of irreducible complexity found within the biological world. Others would include the process of blood clotting, closed circular DNA, electron transport, telomeres, photosynthesis, and transcription regulation (Behe, "Molecular Machines," 33).

Many who are committed to the Darwinian theory of evolution resist the implications of irreducible complexity by suggesting that these complex systems could have evolved from physical precursors which had different purposes and functions from what we observe in the complex systems of today. The illustration has been used of the building of an arch. According to the illustration, a scaffold of some sort was built for the purpose of supporting the arch; then the arch was built and the scaffold was taken down. So, while the arch had one purpose (perhaps to serve as a monument), the scaffold had a different and supporting purpose (to allow the way for the development of the arch). Likewise, perhaps there was some physical precursors to the cell, for example, that aided the cell to come about, and then the evidence for the existence of such a physical precursor was removed.

There are a few major problems with such theorizing. First and foremost, there is absolutely no evidence whatsoever for any kind of physical precursor for the human eye, the cell, or many other irreducibly complex systems. Good science is built on the evidence that we have, not on the evidence that we don't have. This is speculation more than it is investigation. The second problem is that the example itself appeals to an intelligent cause. The third problem is the fact that many simultaneous mutations (all of which would be useful for the one new unified purpose) would be necessary in order to avoid the problem of irreducible complexity. For if only one mutation occurred which served a new purpose different from the rest of the system, that mutation would be weeded out by natural selection. The improbability of such a series of system-wide, simultaneous mutations is astronomical beyond words.

To a scientist who is committed to Darwinian evolution, irreducible complexity poses a massive problem to his paradigm. But "to a person who does not feel obliged to restrict his search to unintelligent causes," says Behe,"the straightforward conclusion is that many biochemical systems were designed" (Behe, "Molecular Machines," 33).

The second great piece of evidence that suggests that life had an intelligent cause is the existence of specified complexity, or information, within biochemistry. When we refer to biological information (specified complexity), we are referring to proteins and DNA, which are the building blocks of living organisms. Specified complexity is much more than mere order. Order in nature is repetitive and simple to explain. For example, dropping a pebble in a pond produces order -- one circular wave, followed by another one outside of that, and so on. Specified complexity, however, is found in something like the words on this very page. There is an order, just as there is with the circular waves in the pond. The difference, however, is that the waves in the water follow a pattern and can be explained simply, while the words on this page do not follow a pattern and cannot be explained simply. Rather, one would have to actually say which letter appears in every given space. There are no short-cuts. This is precisely what we find when we look at proteins and the DNA molecule.

Although natural selection is the very driving force within the Darwinian theory, natural selection cannot be appealed to in an attempt to explain how proteins and DNA appeared. The reason is simple. Natural selection is a principle that is active within organisms that already exist and reproduce. But before the proteins and DNA have been formed, there is no reproducing organism for natural selection to act upon. L. von Bertalanffy put it this way: "Selection, i.e., favored survival of ‘better' precursors of life, already presupposes self-maintaining, complex, open systems which may compete; therefore selection cannot account for the origin of such systems" (L. von Bertalanffy, Robots, Men and Minds, 82). The question of how this biological information came about is crucial. Kuppers even suggests that "the problem of the origin of life is clearly equivalent to the problem of the origin of biological information" (B. O. Kuppers, Information and the Origin of Life, 170-72).

It has been theorized that the polymer chains called proteins were first formed on the earth in a sort of "prebiotic soup." In a prebiotic soup, L-amino acids and D-amino acids (amino acids that are mirror images of each other) would exist in roughly equal numbers and would react with each other randomly, regardless of whether they are L- or D-amino acids. The problem is that proteins found in living creatures today contain only L-amino acids. On top of this, there are 20 different types of L-amino acids, and the order in which they combine is highly important. About half of the sites along the polymer chain are quite critical (called active sites). One wrong amino acid at one of these active sites could prove fatal (ex.: sickle cell anemia).

If we were to attempt to assemble amino acids into functional protein, the probability of getting an L-amino acid would be 50%. The probability of joining two L-amino acids with a peptide bond (necessary for building a polymer chain) also would be 50%. On average, the probability of getting the right amino acid in a particular position would be 5% (since there are 20 different amino acids). So the probability of getting everything right in placing one amino acid would be 0.5 x 0.5 x 0.05 = 0.0125. If a functioning protein has 100 active sights, the probability of getting all of the critical amino acids in the right place would be 0.0125 raised to the 100th power, which would be 4.9 x 10-191. And all of this is assuming that there would be no reactions within the "prebiotic soup" which would deconstruct the protein along the way (which is an unrealistic assumption) (Bradley and Thaxton, The Creation Hypothesis, 178-190). If the probability of proteins coming about naturally is so low, it would seem reasonable to consider the emergence of proteins by intelligent means.

Research chemists now have the ability to synthesize various proteins. But only by highly constraining their experiments and by guiding the process every step of the way can they produce the kinds of proteins found in living things. Far from showing that proteins can be produced by natural processes, this only confirms that proteins come about by intelligent causes (Bradley and Thaxton, The Creation Hypothesis, 209).

Francis Crick and James Watson have gone down in history for their discovery of the double helix molecule know as DNA. DNA is also known as the information molecule. On March 19, 1953, Crick wrote to his son Michael: "Now we believe that DNA is a code. That is, the order of bases (the letters) makes one gene different from another gene (just as one page of print is different from another)."

The double helix structure of the DNA molecule resembles an extremely long ladder twisted into a spiral. While sugar and phosphate molecules form the sides of this ladder, four bases -- adenine, thymine, guanine and cytosine -- make up its "rungs". These bases act as a four-letter genetic alphabet. They combine to form the equivalent of words, sentences and paragraphs. The message within this double helix structure is all that is needed to guide the operations of the cell.

In the 1940s, Claude Shannon of Bell Telephone Laboratories came up with a mathematical means of measuring information. This became known as Information Theory. Information Theory applies to any and all languages, regardless of the elements that make it up. It applies to human language, to Morse-code, and yes, even to the genetic code of DNA. This is because, as Crick said, DNA is a code. This is why we study information theory in biology.

The fact that the genetic code is strikingly similar to other codes and languages is highly significant. Scientists for centuries have used a method of reasoning known as abduction. It is known to be an established principle of scientific investigation. The principle of abduction states that, given two effects that are strikingly similar, one should expect very similar causes. NASA used this line of reasoning to conclude that water used to exist on Mars. When they saw canals on Mars that were very similar to those on Earth, they knew that such canals on Earth were produced by water erosion; so it was reasonable to conclude that the canals on Mars were produced by water erosion as well.

Likewise, it is our experience that the use of languages and codes have intelligent causes, rather than natural causes. Given the fact that the genetic code in DNA is strikingly similar to other codes produced by intelligence, it is very reasonable to conclude that the genetic code was produced by an intelligence as well.

Although this form of reasoning is used by scientists in other fields (such as NASA, SETI, archeology, cryptography, etc.) to determine if something has a natural cause or an intelligent cause, scientists are often unwilling to use abduction in the realm of biochemistry. Part of the reason is because the option of intelligent causation is ruled out of court even before the evidence is heard. For example, Shapiro strongly suggests that all current theories of the origin of life are bankrupt and that we must find a new and more helpful paradigm to guide our search for a naturalistic explanation for the origin of life (Bradley and Thaxton, The Creation Hypothesis, 196). As can be seen, the possibility of intelligent causation is not even considered. In light of the bankruptcy of current naturalistic models, however, perhaps it is time to heed the words of a fresh alternative: "Scientific investigations of the origin of life have clearly led us to conclude that an intelligent cause may, in the final analysis, be the only rational possibility to explain the enigma of the origin of life: information" (Bradley and Thaxton, The Creation Hypothesis, 209).

Sources Used

Behe, Michael, Darwin's Black Box, New York: Simon & Schuster, 1996.

Behe, Michael, "Molecular Machines: Experimental Support for the Design Inference," Cosmic Pursuit, Spr 1998, pp. 27-35.

Bradley, Walter and Thaxton, Charles, "Information and the Origin of Life," The Creation Hypothesis, ed. J. P. Moreland, 1994.

Darwin, C. (1872) Origin of Species, 6th ed. New York: New York University Press, 1988.

Dembski, William. "The Intelligent Design Movement," Cosmic Pursuit, Spr 1998, pp. 22-26.

Kuppers, B. O., Information and the Origin of Life. Cambridge, Mass.: MIT Press, 1990.

Thaxton, Charles. "A New Design Argument," Cosmic Pursuit, Spr 1998, pp. 13-21.

Von Bertalanffy, L., Robots, Men and Minds. New York: George Braziller, 1967.