On Intelligent Design: What should we teach our children?
The official Vatican newspaper published an article this week labeling as "correct" the recent decision by a judge in Pennsylvania that intelligent design should not be taught as a scientific alternative to evolution. This is a major event in the history of mankind as the debate whether we evolved as a species or were put together carefully continues to rage. There is no credible scientific challenge to the idea that evolution explains the diversity of life on earth, but advocates for intelligent design posit that biological life is so complex that it must have been designed by an intelligent source. The debate needs to be studied by all, whether you believe in the intelligent design of not.
Among the chief exponents of Intelligent Design (ID) theory, as this new brand of creationism is called, is William Dembski, a mathematical philosopher and author of The Design Inference. In that book he attempts to show that there must be an intelligent designer behind natural phenomena such as evolution and the very origin of the universe. Dembski’s argument is that modern science ever since Francis Bacon has illicitly dropped two of Aristotle's famous four types of causes from consideration altogether, thereby unnecessarily restricting its own explanatory power. “Science is thus incomplete, and intelligent design theory will rectify this sorry state of affairs.”
Aristotle identified material causes, what something is made of; formal causes, the structure of the thing or phenomenon; efficient causes, the immediate activity producing a phenomenon or object; and final causes, the purpose of whatever object we are investigating. Dembski maintains that Bacon and his followers did away with both formal and final causes (the so-called teleonomic causes, because they answer the question of why something is) in order to free science from philosophical speculation and ground it firmly into empirically verifiable statements. That may be so, but things certainly changed with the work of Charles Darwin (1859). Darwin was addressing a complex scientific question in an unprecedented fashion: he recognized that living organisms are clearly designed in order to survive and reproduce in the world they inhabit; yet, as a scientist, he worked within the framework of naturalistic explanations of such design. Darwin found the answer in his well-known theory of natural selection. Natural selection, combined with the basic process of mutation, makes design possible in nature without recourse to a supernatural explanation because selection is definitely nonrandom, and therefore has "creative" (albeit nonconscious) power. Creationists usually do not understand this point and think that selection can only eliminate the less fit; but Darwin's powerful insight was that selection is also a cumulative process-analogous to a ratchet-which can build things over time, as long as the intermediate steps are also advantageous.
There are two additional arguments proposed by ID theorists to demonstrate intelligent design in the universe: the concept of "irreducible complexity" and the "complexity-specification" criterion. Irreducible complexity is a term introduced in this context by molecular biologist Michael Behe in his book Darwin's Black Box. The idea is that the difference between a natural phenomenon and an intelligent designer is that a designed object is planned in advance, with forethought. While an intelligent agent is not constrained by a step-by-step evolutionary process, an evolutionary process is the only way nature itself can proceed given that it has no planning capacity (this may be referred to as incremental complexity). Irreducible complexity then arises whenever all the parts of a structure have to be present and functional simultaneously for it to work, indicating-according to Behe-that the structure was designed and could not possibly have been gradually built by natural selection.
1. It is simply not true that science does not address all Aristotelian causes, whenever design needs to be explained;
2. While irreducible complexity is indeed a valid criterion to distinguish between intelligent and non-intelligent design, these are not the only two possibilities, and living organisms are not irreducibly complex.
3. The complexity-specification criterion is actually met by natural selection, and cannot therefore provide a way to distinguish intelligent from non-intelligent design;
4. If supernatural design exists at all, this is certainly not of the kind that most religionists would likely subscribe to, and it is indistinguishable from the technology of a very advanced civilization.
What is intelligent design?
"Intelligent design" consists of two hypothetical claims about the history of the universe and of life: first, that some structures or processes in nature are "irreducibly complex" and could not have originated through small changes over long periods of time; and second, that some structures or processes in nature are expressions of "complex specified information" that can only be the product of an intelligent agent.
What is evolution?
Evolution is a broad, well-tested description of how Earth's present-day life forms arose from common ancestors reaching back to the simplest one-celled organisms almost four billion years ago. It helps explain both the similarities and the differences in the enormous number of living organisms we see around us. By studying the sequence of changes in fossils found in successive layers of rock as well as the molecular evidence provided by modern genetics, scientists have been able to trace how ancient organisms — through a process of descent with modification — gave rise to profound changes in populations over time. Many new anatomical forms have appeared, while others have disappeared. In a very real sense, we are distant genetic cousins to all living organisms, from bacteria to whales. Evolution occurs in populations when heritable changes are passed from one generation to the next. Genetic variation, whether through random mutations or the gene shuffling that occurs during sexual reproduction, sets the stage for evolutionary change. That change is driven by forces such as natural selection, in which organisms with advantageous traits, such as color variations in insects that cloak some of them from predators, are better enabled to survive and pass their genes on to future generations. Ultimately, evolution explains both small-scale changes within populations and large-scale changes in which new species diverge from a common ancestor over many generations.
Is evolution "just a theory?"
In detective novels, a "theory" is little more than an educated guess, often based on a few circumstantial facts. In science, the word "theory" means much more. A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. The theory of biological evolution is more than "just a theory." It is as factual an explanation of the universe as the atomic theory of matter or the germ theory of disease. Our understanding of gravity is still a work in progress. But the phenomenon of gravity, like evolution, is an accepted fact.
Is there "evidence against" contemporary evolutionary theory?
No. There are still many puzzles in biology about the particular pathways of the evolutionary process and how various species are related to one another. However, these puzzles neither invalidate nor challenge Darwin's basic theory of "descent with modification" nor the theory's present form that incorporates and is supported by the genetic sciences. Contemporary evolutionary theory provides the conceptual framework in which these puzzles can be addressed and points toward ways to solve them.
Is there a growing body of scientists who doubt that evolution happened?
No. The consensus among scientists in many fields, and especially those who study the subject, is that contemporary evolutionary theory provides a robust, well-tested explanation for the history of life on earth and for the similarity within the diversity of existing organisms. Very few scientists doubt that evolution happened, although there is lively ongoing inquiry about the details of how it happened. Of the few scientists who criticize contemporary evolutionary theory, most do no research in the field, and so their opinions have little significance for scientists who do.
Is intelligent design a scientific alternative to contemporary evolutionary theory?
No. Intelligent design proponents may use the language of science, but they do not use its methodology. They have yet to propose meaningful tests for their claims, there are no reports of current research on these hypotheses at relevant scientific society meetings, and there is no body of research on these hypotheses published in relevant scientific journals. So, intelligent design has not been demonstrated to be a scientific theory. While living things are remarkably complex, scientists have shown that careful, systematic study of them can yield tremendous insights about their functions and origins (as it has in the past). Intelligent design necessarily presupposes that there is an "intelligent designer" outside of nature who, from the beginning or from time to time, inserts design into the world around us. But whether there is an intelligent designer is a matter of religious faith rather than a scientifically testable question.
Are science and religion inherently opposed?
No. Science does not take a position on an intelligent designer, which is a matter of religious faith, and is not testable scientifically. Science and religion ask different questions about the world. Many individual scientists are deeply religious. They see scientific investigation and religious faith as complementary components of a well-rounded life.
Can science stimulate religious thought?
Yes. A particular religion's understanding of the world provides the context from which questions of meaning emerge. A development in science may provide a new more reliable explanation of the structure and processes of the world. This may be different from the understanding of the world that is presumed in a particular religion. What may appear to be a conflict between science and religion is actually a contrast between earlier and more recent understandings of the world (e.g., between an earth-centered universe and a sun-centered universe) and can be a constructive stimulus for religious inquiry. In fact, Jewish, Christian, Muslim, Buddhist and Hindu scholars have sought positive ways to relate evolutionary theory with their religious traditions.
Is the science classroom the appropriate place to discuss the religious interpretations of science?
No. Religion is a subject of inquiry in historical, philosophical and social studies, not in science. So, discussion about religion is most appropriate in the social studies or humanities curriculum, not in the science curriculum.
What are the stakes?
The risk, if intelligent design is incorporated into school curricula, is to undermine scientific credibility and the ability of young people to distinguish science from non-science. And that is what matters more, in the longer term, than the specific battles over intelligent design versus evolution.