page_title: Objections to evolution
section_title: Creation of complex structures
hierarchical_section_title: Objections to evolution / Impossibility / Creation of complex structures
context_page_description: Objections to evolution have been raised since evolutionary ideas came to prominence in the 19th century. When Charles Darwin published his 1859 book On the Origin of Species, his theory of evolution initially met opposition from scientists with different theories, but eventually came to receive overwhelming acceptance in the scientific community. The observation of evolutionary processes occurring has been uncontroversial among mainstream biologists since the 1940s.
  Since then, most criticisms and denials of evolution have come from religious groups, rather than from the scientific community. Although many religious groups have found reconciliation of their beliefs with evolution, such as through theistic evolution, other religious groups continue to reject evolutionary explanations in favor of creationism, the belief that the universe and life were created by supernatural forces. The U.S.-centered creation–evolution controversy has become a focal point of perceived conflict between religion and science.
context_section_description: Living things have fantastically intricate features—at the anatomical, cellular and molecular level— that could not function if they were any less complex or sophisticated. The only prudent conclusion is that they are the products of intelligent design, not evolution.
  — Jonathan Sarfati, quoting Scientific American editor John Rennie
  Modern evolutionary theory posits that all biological systems must have evolved incrementally, through a combination of natural selection and genetic drift. Both Darwin and his early detractors recognized the potential problems that could arise for his theory of natural selection if the lineage of organs and other biological features could not be accounted for by gradual, step-by-step changes over successive generations; if all the intermediary stages between an initial organ and the organ it will become are not all improvements upon the original, it will be impossible for the later organ to develop by the process of natural selection alone. Complex organs such as the eye had been presented by William Paley as exemplifying the need for design by God, and anticipating early criticisms that the evolution of the eye and other complex organs seemed impossible, Darwin noted that:
  [R]eason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real.
  Similarly, ethologist and evolutionary biologist Richard Dawkins said on the topic of the evolution of the feather in an interview for the television program The Atheism Tapes:
  There's got to be a series of advantages all the way in the feather. If you can't think of one, then that's your problem not natural selection's problem... It's perfectly possible feathers began as fluffy extensions of reptilian scales to act as insulators... The earliest feathers might have been a different approach to hairiness among reptiles keeping warm.
  Creationist arguments have been made such as "What use is half an eye?" and "What use is half a wing?". Research has confirmed that the natural evolution of the eye and other intricate organs is entirely feasible. Creationist claims have persisted that such complexity evolving without a designer is inconceivable and this objection to evolution has been refined in recent years as the more sophisticated irreducible complexity argument of the intelligent design movement, formulated by Michael Behe.  Biochemist Michael Behe has argued that current evolutionary theory cannot account for certain complex structures, particularly in microbiology. On this basis, Behe argues that such structures were "purposely arranged by an intelligent agent."
  Irreducible complexity is the idea that certain biological systems cannot be broken down into their constituent parts and remain functional, and therefore that they could not have evolved naturally from less complex or complete systems. Whereas past arguments of this nature generally relied on macroscopic organs, Behe's primary examples of irreducible complexity have been cellular and biochemical in nature. He has argued that the components of systems such as the blood clotting cascade, the immune system, and the bacterial flagellum are so complex and interdependent that they could not have evolved from simpler systems.
  In fact, my argument for intelligent design is open to direct experimental rebuttal. Here is a thought experiment that makes the point clear. In Darwin's Black Box (Behe 1996) I claimed that the bacterial flagellum was irreducibly complex and so required deliberate intelligent design. The flip side of this claim is that the flagellum can't be produced by natural selection acting on ran
caption: The bacterial flagellum has been invoked in creation science and in intelligent design to illustrate the concept of irreducible complexity. Careful analysis shows that there are no major obstacles to a gradual evolution of flagella.