Evolution, Natural Selection, and Intelligent Design By Emiliano Navarrette
The evolution of organisms is a central concept in biology. Yet theories concerning evolution have provoked passionate debate far beyond the scientific community. In my view, the debate over biological evolution is a focal point in a much broader conflict between two basic worldviews, one scientific and one religious. A full treatment is beyond the scope of this essay. I will instead focus on three concepts- evolution, natural selection, and intelligent design- as they figure into the current debate over what ought to be the proper curriculum for biology. It is important to note that contention over the teaching of evolution is a separate debate from the contention over issues in evolution among biologists. The two become muddled in public discourse, both by semantic accident and rhetorical design. Intelligent design is, in my estimation, given undue weight by factors outside the scientific community. Specifically, it is used as a tool by a sizable minority of evangelical Christians who wish to undermine a worldview they deem detrimental to their own. I will not argue against this as a moral position, but I do believe that if we wish to teach science in public schools, the scientific consensus ought to shape the curriculum rather than political pressure. Intelligent design, lobbied for as a valid scientific theory equal to evolution by natural selection, is in fact a lever for this political pressure. On the basis of scientific merit, intelligent design should not be given equal treatment with evolution and natural selection in the biology classroom.
Evolution can be defined as "changes in gene frequency in a population over time" (Postlethwait and Hopson 1992). Genes are the blueprints of organisms, so evolution entails fundamental change. Observation of living animals and the fossil record gives ample evidence that evolution is a fact. Thus the commonly used phrase "theory of evolution" is misleading; biologists theorize about the mechanism of evolution- the fact that evolution has occurred and continues to occur is agreed upon by the vast majority of biologists (Moran 2002). The use of the word "theory" confuses public discourse on the topic as well. The scientist uses the word to mean something like a systematic and plausible explanation for an observation or set of observations (Moran 2002). In general speech, "theory" can have much less rigorous application- it is most often used as a synonym for "speculation" or "conjecture." The human imagination being what it is, all sorts of "theories" in the loose sense abound. Some who rail against the theory of natural selection would have you believe it shares equal footing with wild conspiracy theories- a deliberate confusion of the terms.
Natural selection may be understood intuitively by artificial selection- dog breeding by humans, for example. Favorable traits are more likely to be passed on, whether man or nature is doing the selecting (Gould 1977). Natural selection proposed by Darwin and elaborated by biologists ever since, is a scientific theory: it proposes an explanation of how the observed phenomena of evolution came to be. It is broadly accepted as one mechanism, if not the only, by the vast majority of biologists (Moran 1997). If the scientific consensus holds the concepts of evolution and natural selection as valid and central to the science, it stands to reason that a biology curriculum should reflect this.
There were, and are, objections to natural selection. Among the first was the concept of intelligent design. The meat of the argument of is that there are creatures in nature that possess a form so perfect or uniquely suited to their surroundings that a series of gradual changes, such as natural selection would entail, would be hard pressed to account for their existence. We have seen examples on video in this class : a fish that looks exactly like a stone, or an insect that looks exactly like a bird dropping- how would natural selection work on an ancestor that looked nothing like a stone or a dropping and without any intelligent plan end up with such creatures? How would the intermediate animals survive? The natural selection advocates refute the objection easily, if not intuitively: the intermediate adaptations serve a different purpose than the final form (Gould 1977).
Is intelligent design a scientific theory? I would say it can be dressed up, in a pinch, to look like one, but it is a weak one at best. It is more accurately a collection of objections that have been already been answered. If the vast majority of biologists favor natural selection over intelligent design, a biology class or textbook ought to reflect this, rather than putting them on an equal footing. Scientific consensus changes. Perhaps someday the consensus will be something along the lines of intelligent design, though the intelligent designer would most assuredly not be the god featured in the creation myth of Genesis. I believe that proponents of intelligent design know this well; they argue for equal consideration in the classroom not to further scientific debate, but to undermine the scientific worldview with an eye to increasing the persuasive power of their own.
References
Gould, SJ. 1977. Ever since Darwin. New York: W.W. Norton and Co. 285p.
Moran, L. 1997. What is evolution? Talk Origins website. available from: http://www.talkorigins.org/faqs/evolution-definition.html. Accessed 2004 Nov 15.
Moran, L. 2002. Evolution is a fact and a theory. Talk Origins website. available from: http://www.talkorigins.org/faqs/evolution-fact.html. Accessed 2004 Nov 15.
Postlethwait, J and Hopson J. 1992. The Nature of Life. New York: McGraw-Hill Inc. 792 p.