Assumption Four, Part Two: "Irreducible Complexity" *
In assumption two, “Order Evolved from Disorder,” I pointed out that the entire universe is “fine-tuned” with incredible precision to support life on earth (the Anthropic Principle). This is demonstrated by the fact that there are several dozen fundamental constants—precise physical parameters—in place throughout the cosmos, including our solar system, that are essential to sustain life on earth. If any of these constants differed even minutely, life would be impossible. This remarkable phenomenon is powerful evidence for creation by intentional design (teleology).
Since the development of the electron microscope in the late 1930s, research into the structure of the cell has progressively revealed that the same incredible design observed throughout the universe is also found in the smallest particles of living matter. Even at a molecular level, single-celled organisms are comprised of numerous complex, precisely constructed, interacting parts, which biochemist Michael Behe calls molecular machines. These tiny protein “machines” are structures within a cell that have no evolutionary pathway and, therefore, could not have evolved through natural, random processes (chance). Behe refers to this evolutionary black box as “irreducible complexity.”
In order to see why there is no evolutionary pathway for these molecular machines, it’s necessary to understand how natural selection works. According to the evolutionary paradigm, all the individual parts of a cell (or of an entire organism, for that matter) are a product of natural selection, which works by making tiny, random improvements in function. Natural selection itself has no power to create new structures from scratch; it only acts on existing designs already built into a system. In the case of a cell, this means natural selection can’t begin to operate until at least a minimum number of molecular machines are already operational and thus have function. The challenge for evolutionists is demonstrate how these preexisting machines originated. They cannot be products of evolution because natural selection can’t kick in until after the integrated parts comprising a molecular machine are fully developed and operating as a unit. If any part is missing or had no function, there would be nothing on which natural selection could act. This is irreducibly complexity.
Behe illustrates this concept by comparing it to a mousetrap, which is comprised of five parts (base, spring, hammer, holding bar, and trigger). If any one of these parts is missing, or not fully formed and functioning, the mouse trap wouldn’t work. A part spring or part trigger would have no function, so it couldn’t “evolve" to become a more improved part spring or part trigger. Only a fully formed mousetrap would have function.
Behe and other researchers provide a variety of examples of irreducible complexity. They point out, for example, that some bacteria cells have a microscopic protrusion (a molecular machine) called a flagellum, which allows the cell to move about—something like an outboard motor. This protein machine is composed of numerous interacting parts, which must all be in place and fully functioning before the flagellum can operate. The bacteria flagellum is irreducibly complex. The individual parts could not have evolved bit-by-bit because each stage would have no function on which natural selection could operate. In other words, if any one of the individual parts comprising the flagellum was not fully formed and working at the very beginning, there could be no flagellum. Thus, like a mousetrap, only after the flagellum is fully operational would it have function and natural selection could begin—but of course (like the mouse trap) the flagellum is already complete and there is nothing to evolve. I never heard anyone claim bacteria flagellum evolved into something else.
The inability of natural selection to create molecular machines because of a lack of function in precursor parts may be easier to understand if considered on a larger scale. Think of a reptile leg evolving into a bird wing. A part leg/part wing at any stage of development would not benefit either a reptile or an evolving bird. It would have no survival value (or function) to permit natural selection. Try to imagine a lizard successfully chasing insects with legs slowly developing feathers and feet designed for perching rather than running. It would hinder the lizard, not help it catch prey. Furthermore, the leg-to-wing scenario is only one of countless other features that would have to evolve simultaneously during the whole evolutionary process of a reptile changing into a bird. Along with wings and feathers and perching feet, an evolving bird would also have to slowly, over eons of time, develop hollow bones, a unique and entirely different respiratory system, and change from being cold-blooded (like reptiles) to warm-blooded. None of these intermediate stages would have any function in terms of survival value. Again: no function, no survival value, no evolution. (By the way, there is no fossil evidence of intermediate stages between reptiles and birds—as you’ll see in a future blog article.)
A typical cell contains many thousands of different kinds of proteins, and the human body has around a100 trillion cells—all of them working in harmony to maintain our bodies. Since evolution cannot account for irreducibly complex protein machines like the flagellum—let alone a lizard leg evolving into a bird wing—the only other option for their origins is a designer who created them. Irreducible complexity provides additional compelling evidence, especially at a cellular level, that naturalistic evolution is a philosophical assumption—not demonstrable science. This will become even more obvious in my next blog article, which will explore a relatively new evidence for creation by design called “Information theory”—which demonstrates the inability of material properties to create information.
* This and the other blog articles in this series are copyrighted material and may not be reproduced electronically or in print. But feel free to link this blog to your own website, blog, or Facebook. I explore irreducible complexity (and other Intelligent Design evidences) more fully in my book The Christian Combat Manual (AMG Publishers), and my sources are documented there.