In the United States, the public face of the science of intelligent design (ID) is an advocacy movement to change the way evolution is taught. Michael Behe is one of the leaders of the movement because of his concept of the irreducible complexity of molecular machinery (Darwin's Black Box: The Biochemical Challenge to Evolution). In this latest book he distances himself from this movement to a certain extent:
...I spend the bulk of the chapters drawing on molecular evidence, genomic research, and--above all--crucial long-term studies of evolutionary changes in single-celled organisms to test Darwinism without regard to conclusions of design. ... As I will argue, mathematical probabilities and biochemical structures cannot support Darwinism's randomness, except at the margins of evolution. Still, as we seek to find the line marking the edge of randomness, there is no need to infer design. (p. 8)The organisms are malaria and the HIV virus, which have evolved defenses against man-made drugs. Despite the huge numbers of organisms and cell divisions observed, there has been no build-up of molecular machinery. Behe likens these observations to the famous experiment in 1887 proving that light propagated in a vacuum, not a luminiferous ether. The ether had to behave like a solid for electric fields and behave like a gas for planets, but it was a good theory at the time. The book makes the case against Darwinian evolution so strongly that biologist will have to come to grips with ID someway. Biology has been able to avoid the question of the evolution of the human soul because it is understood that evolution only applies to the bodies of human beings. This cannot be explicitly stated because the very concept of the "body of a human being" is an existential or metaphysical concept, not a scientific concept. The following quote by a famous authority on evolution and an outspoken secular humanist proves this point:
Catholics could believe whatever science determined about the evolution of the human body, so long as they accepted that, at some time of his choosing, God had infused the soul into such a creature. I also knew that I had no problem with this statement, for whatever my private beliefs about souls, science cannot touch such a subject and therefore cannot be threatened by any theological position on such a legitimately and intrinsically religious issue. (Stephen Jay Gould, "Nonoverlapping Magisteria," Natural History, March 1997, 13th paragraph)
Gould is mistaken in calling the soul a "religious issue." That God will save our souls is a religious belief, but that we have souls is a metaphysical or existential truth. The statement that human beings do not have souls is also a metaphysical statement, not a scientific statement. (I sure Gould's "private beliefs" don't make any sense. Humans have souls because they are embodied spirits. Humans are embodied spirits because they are indefinabilities. Humans are indefinabilities because free will and conscious knowledge can't be defined. Of course, Gould may think free will is an illusion, but he knows that this point of view would make him look foolish in some circles.)
However, biologists cannot continue to ignore the observations about the evolution of malaria and the complexity of multicellular life. The solution can't be to consider the possibility of a designer because this would fail to keep science separate from existentialism. But the time has come for biologist to incorporate the concept of design and William Dembski's concept of specified complexity (The Design Revolution: Answering The Toughest Questions About Intelligent Design) into their understanding of evolution.