Saturday, 25 June 2011

Irreducible complexity - another myth

One of the common arguments against evolution, put forward by the creationists, is that of supposed irreducible complexity.   The term was coined by the notorious proponent of 'Intelligent Design', Michael Behe, but the idea itself is much older.  In the 18th century William Paley used a watch as an analogy of the world in an attempt to 'prove' that there was evidence of design all around us.  Darwin had to study Paley's works of philosophy at university, and it seems that he recognised flaws in the arguments. People had inferred the existence of a creator from their own lack of an explanation - from their own ignorance..

Darwin addressed this in his own works.  In the introduction to the Descent of Man he wrote:

"Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science."

Of course the arguments of creationists might be easy to refute but it is difficult to make them listen.  Even when there is clear evidence against their 'appeal to ignorance' approach they will not change their point of view.  They make claims that don't make sense, including the common idea that "half an eye is no use to anyone".  They say that they cannot imagine how an eye could possibly have evolved and that it must have been created in its complete final form.

But in fact, the evolution of the eye can be seen at every necessary stage of evolution in living or fossilised animals.  In this video, Richard Dawkins explains why half an eye really is better than no eye at all.

[The video that was originally embedded here was withdrawn from Youtube - but here is a replacement which is just as good -- 29th January 2012]

Incidentally, it is thought that eyes have evolved independently on at least 10 different occasions so far.  The alternative that you might find most familiar is the compound design that is common in insects.  Our own 'design' has been around for about half a billion years, having originally evolved in a fishy ancestor.

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