Behe proposes that intelligent design is needed to produce these systems. This idea has drawn many criticisms. However, each major criticism can also be critiqued. These critiques leave Behe s ideas of irreducible complexity and intelligent design still standing as viable options. This is a new version of the God of the gaps.
Gene duplication provides the complexity.
Evolution can create systems from genes that are already around for other purposes. Some steps of evolution are no longer seen, but were there before a system looked irreducibly complex. Some seemingly complex systems initially worked at a simpler level, which eventually evolved to a more complex, even an irreducibly complex system. Today, we can see examples of genetic evolution that support some of the above criticisms. The book Darwin's Black Box , by biochemistry professor Michael Behe, has challenged the idea that Darwinian evolution explains many of the complex biochemical systems we see today.