Why intelligent design is a supernatural theory, rather than a scientific theory

"Scientific theory":Definition: [n]  a theory that explains scientific observations; "scientific theories must be falsifiable"A scientific theory differs from any form of theory, which is defined as:

  1. [n]  a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
  2. [n]  a belief that can guide behavior; "the architect has a theory that more is less"; "they killed him on the theory that dead men tell no tales."

Thus, any idea can be called a "theory," but a scientific theory is more narrowly defined as something that explains a natural phenomenon and provides testable predictions that can be "falsifiable" (i.e., "proven false"). 

Evolution by natural selection is a scientific theory, in that it claims that current variation among organisms arose by billions of generations of selection of the "most fit" ancestral organisms that changed in form and function over the eons.  Evolution by natural selection makes a suite of predictions about how organisms are related to one another, how certain "selective pressures" (e.g., predators, availability of mates, global warming) will affect body form and function, and how the fossil record should be structured.  Many of these predictions have been tested by collecting data using the scientific method, and comparing these data to the predictions of evolution by natural selection.  Thus, evolution is a bona fide scientific theory that has strong empirical support (i.e., there are a LOT of data backing up evolution).

Intelligent design is more an "anti-scientific theory" in that most of its proponents attempt to gain support by criticizing the theory of evolution, instead of doing any research to test their own theory.  This is not how science works.  A scientific theory cannot be assembled by negating another theory!  For intelligent design to be a bona fide theory it needs to make one or more testable predictions that can be addressed using scientific methods and processes.  The only thing close to a prediction forwarded by proponents of intelligent design is that certain biological traits (e.g., eyes or microtubules) are so complex that they cannot be the end result of a gradual series of incremental changes favored by natural selection (they call these purported traits "irreducibly complex"). The closest ID proponents have come to producing testable hypotheses is the claim that certain features of living organisms have no biological function if there are parts missing. Asserted examples (e.g. flagella, cilia, blood clotting mechanisms) have all failed because in each case a related organism was found that used some but not all of the parts making up the purported “irreducibly complex” system. But mostly, ID proponents assert the lack of detailed knowledge of the evolutionary history of a particular organism or structure as evidence that science will never be able to explain such organisms or structures. Again, they are using the theory of evolution as their basis (in a negative sense) and stating "if it hasn't been explained yet by evolution by natural selection, then it never will be and thus must have been created by a supernatural intelligence." This way of thinking is antithetical to the entire enterprise of science. Science is driven by the expectation that natural explanations will be found for natural phenomena – even though the road may be long and bumpy. Intelligent design shuts off inquiry as soon as the going gets tough and invokes an unscientific, supernatural agent. Thus, in no way is intelligent design a "scientific theory."

Then what type of theory is intelligent design?  The proponents of this theory claim that biological complexity was "designed" by a supernatural being, and that if we look hard enough, this will become obvious.  A creation of something from nothing by a supernatural being can only be considered a "supernatural theory," that would fall under the first definition of theory above: "a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena." 

For"intelligent design" to EVER be treated as a serious scientific theory by the scientific community, it must create a set of testable predictions that can be falsified.  Intelligent design has not attained this level, and thus is not science.  Therefore, it should not be taught in the science classroom.

In no way does the above statements suggest that intelligent design should be "hidden from our children." Rather, they suggest that intelligent design should come clean about its true nature and compete among other supernatural explanations, rather than trying to take time away from real science instruction. It is a viable supernatural theory, and thus could be presented in courses that deal with such subject matter, such as religious studies courses.  Placing this theory in a science course will only confuse students as to what science is all about, and thus will be counter-productive.  As educators, we should strive to teach the appropriate material in the appropriate courses rather than befuddle our students by mixing non-scientific material in with bona fide science curricula.