If Intelligent Design is to be taken seriously as a scientific theory, the “intelligent designer” in question cannot be a supernatural cause. (See “Is Intelligent Design a Science?”) The best case for Intelligent Design envisions intelligence as a natural phenomenon, to be approached like any other aspect of nature.
It is well-known that intelligence can influence the course of evolution. Human beings have been intelligently guiding and altering the course of evolution for ages.
In his Origin of Species, Darwin distinguished between artificial selection and natural selection. Artificial selection, more commonly known as “breeding,” is evolution guided by human intelligence. Natural selection, which is what most people mean by the word “evolution,” is shaped by the unknowing hand of nature.
The theoretical possibility of there being some other, non-human intelligence at work in the process of evolution must be acknowledged. However, any such intelligence would be observable and measurable, just as human breeding is an observable, measurable phenomenon.
Furthermore, any such intelligence would be worthy of an explanation. Claiming that some other intelligence is responsible for humanity does not explain humanity, nor does it explain evolution. It merely adds another phenomenon to the list of that which scientists must explain.
The notion of an intelligent designer raises just as many questions as it purports to answer. Trying to explain the fact of humanity by making reference to an unexplained form of intelligence is a case of begging the question. That is, it does not arrive at a conclusion through valid reasoning, but instead assumes the conclusion it wishes to find.
As evolutionary biologist Richard Dawkins points out in The God Delusion, any being capable of designing humanity would be as difficult to explain as humanity itself. The point is, invoking the notion of an intelligent designer does not answer the questions evolutionary theory is capable of answering. Instead, it assumes a conclusion and tries to avoid scientific inquiry in the process.
The fact is, there are no significant problems with evolutionary theory. There are tomes detailing undisputed evidence in support of the view that humanity is the result of a blind process of genetic mutation and natural selection. Furthermore, the theoretical power of evolutionary theory is of enormous value, and remains a wellspring of inspiration and insight for scientists in many fields.
The best case for Intelligent Design is therefore not as an alternative to evolutionary theory. On the contrary, evolutionary theory is indispensable in explaining the origins of complex life forms. If some non-human intelligence is found to have had a hand in the origins of life and humanity, evolutionary theory will only help scientists understand how it happened.
Dawkins, Richard, The God Delusion (Houghton Mifflin, 2006)