Irreducible Complexity


The evolution of the wing has been mentioned. A sufficiently developed wing was described as having mutated from the foreleg of a reptile - quite rapidly (within one generation). Perhaps that is not how you understood evolution to work. Admittedly, those statements may not be completely correct. They were purposed to introduce this topic. For this, we need to backtrack a bit.

Prior to Darwin’s launching the theory of evolution, a man by the name of William Paley made a case for the existence of God in creation. This was effectively known as the ‘argument from design’. His famous analogy was that of the design and workings of a watch. Paley proposed that if you were to throw together all the materials used in the making of the watch, and leave them to be acted upon by random events, you would never expect to see a watch emerge. Only if a designer and craftsman were to come along and use the materials, would a watch result. The designer (God) is implicit in the design and function of all we see in creation.

Atheistic evolutionists have argued that random events caused the random makings of infinitesimally small parts of the ‘watch’. Being random though, these developments would be unmade as easily as they were made. This is how ‘natural selection’ came to play a part. Natural selection is effectively the ‘survival of the fittest’. It means that any life forms that undergo a beneficial mutation (change), would thrive and reproduce1 because of it’s advantage over inferior types/species. Natural selection is therefore the proposed mechanism by which random changes in life forms progress along the evolutionary road. And so life forms evolve from simple to complex. Most evolutionists understand all this to mean that creatures have evolved very slowly, one very small step at a time, over very long periods.

So why speak of the evolution of the wing in such radical terms. The issue here is something known as ‘irreducible complexity’. It breathes fresh life into the argument from design. The crude example of the wing is not necessarily accurate, but will be used to illustrate the point. For more accurate examples, read Michael J. Behe’s book, Darwin’s Black Box: The biochemical challenge to evolution.

Here is a quote from Darwin himself:

"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."

Irreducible complexity takes up the challenge.

In the first half of this discussion, the terms ‘natural selection’ and ‘the argument from design’ were introduced. They are key to understanding ‘irreducible complexity’ in all its fullness.

All biological systems (let’s call them organs) have a function. They achieve that function through a number of subsystems/parts working together. The smallest set of parts necessary for the organ to still achieve its function, is known as its irreducible complexity. Anything simpler than this set would render the organ useless. The organ requires its functionality in order to be beneficial, and therefore survive natural selection. The problem is that in the evolution of all these sub-systems, the benefit of each successive development would not be realised until the irreducibly complex system had evolved. Therefore natural selection will not aid the evolutionary process at this level. The design or purpose of the organ, rather than natural selection, appears to be the motivating factor in the existence of the sub-systems.

Evolution was described as occurring in very small increments over a very long time. With recent breakthroughs in biochemistry and the understanding of the complex chemical mechanisms at work in biological organs, ‘small’ is no longer small enough. When Darwin laid the foundations for evolutionary theory in the 19th century, it was assumed that the cell was no more complex than ‘a simple lump of albuminous carbon’. Scientists of the day had a fairly simplistic understanding of biochemistry and the physiology of major organs.

Let’s return to the hypothetical wing by way of an example. There would be no benefit in having an adapted skeletal structure for flight without feathers (or adapted ‘hand’ without adapted ‘shoulder’). The mutated ‘hand’ would only disadvantage the animal unless used for flight. If a mutation were merely neutral (‘say’ feathers), it would not emerge in a new species due to the inefficacy of natural selection. And why should a myriad of other neutral mutations (sub-systems of the wing) necessary for flight, randomly emerge without yet achieving the goal and benefit of flight. Under these conditions, these mutations would be lost. To rationalise the evolution of the wing, a very specific order and timing of ‘small’ mutations would be required. Even then, the trouble would be that these small mutations are not as small as they may seem. Each is a complex biological system of its own - also subject to irreducible complexity. And so the probability of it all dwindles, that not even billions of years of random to and fro-ing could fix.

With some organs, such as the eye in Prof. Behe’s book, it is even harder to conceive its evolution. Not by any sequencing or timing of micro-evolutionary processes. Each biochemical sub-system is necessary for an eye to function and would achieve no purpose on its own.

We stand, yet again, in awe of the Designer who fashioned His ‘watch’ and purposed its function. Despite years of abuse, the argument from design still stands.

1. A basic assumption of evolution is that of reproduction. Without it there would be no benefit in natural selection.

Becky Conolly

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