Intelligent Design vs. Evolution: Theories, Cases & Opinion

Introduction: The Central Question of Speciation

One of the major issues concerning evolution and speciation — or, rather, how the flora and fauna we see around us came to be, starting from species that are largely now extinct — is the process or mechanism by which they occurred.

Intelligent Design (ID) advocates believe that the species we observe on earth today are the result of creationism: that some "intelligent" cause was responsible for what we observe, rather than a process of natural selection, and that everything we see today was created at the beginning of time, simultaneously, as described in the Bible. To give it a scientific framing, Intelligent Design theorists hold that a Christian God is the Intelligent Designer. For example, the existence of a cell in an organism is treated as a supernatural phenomenon. One of the common examples given by ID proponents is that for a single cell in an organism to have evolved by random occurrence alone, the odds would be 1 in 10^40,000 (Skjaerlund, n.d.).

The other primary scientific theory about speciation and evolution arises from the contributions of Charles Darwin, who theorized survival of the fittest, or evolution by natural selection (Seward 1909). Other aspects of evolutionary theory that are no longer seriously contested include changes caused by mutations, whether inherited or through epigenetics — changes forced by the surroundings or environment — an idea first proposed by Hugo De Vries (Stamhuis, Meijer, and Zevenhuizen 1999).

Two Models of Evolutionary Change

There are two major theories for the evolution of organisms and speciation: phyletic gradualism and punctuated equilibrium. This distinction has been the focus of an ongoing debate spanning several decades. Phyletic gradualism, as the name suggests, involves evolutionary changes that occur in individuals through beneficial mutations. These changes often arise in response to shifts in the environment and then spread across a population over generations as the mutated gene achieves dominance through interbreeding.

Punctuated equilibrium, by contrast, stands in direct opposition to phyletic gradualism (Eldredge and Gould 1972). According to this theory, major changes occur through radical mutations that transform a species — or its immediate offspring — into an entirely new species. Once the change has occurred and the surrounding environment stabilizes, the species undergoes no major further changes until the next upheaval. The theory also holds that radical mutations allow the new species to reproduce such that an entity distinct from the parent species becomes established. The intervening periods of stability are referred to as periods of stasis.

Critiquing Each Theory

Intelligent Design has been soundly criticized by scientific and educational organizations. The criticisms center on the argument that ascribing supernatural causes to natural phenomena does not constitute science. These groups maintain that for something to qualify as science, it must involve hypothesis testing in laboratory or experimental settings. ID proponents and creationists, for their part, mock Darwin's theories as incomplete, arguing that there is no fossil evidence showing a continuous progression of evolution — for example, from lower primates to great apes to humans, the so-called "missing link." They contend that speciation as we observe it is not composed of logical steps and that every species is complete in and of itself. In her book critical of liberal thought, Godless (Coulter 2006), conservative commentator Ann Coulter asks why every fossil found represents a complete and potentially functional individual organism, with no evidence of the "mistakes" that natural selection is said to have eliminated.

Before examining the critiques of Intelligent Design, it is worth exploring two of its foundational tenets. ID treats every object as complete and functional, the creation of a supernatural designer. Michael Behe, one of the principal defenders of Intelligent Design, uses the example of a mousetrap to illustrate this, through a concept he called "irreducible complexity" (Behe and Singh 2005). Behe argues that several components go into making a mousetrap — wood, metal, springs, and bait — and that a grand design is responsible for assembling these components so that they perform a specific function. By themselves, he contends, each component is not only unable to perform that function but is essentially useless. Opponents counter that while this may be true in isolation, each component can also function in other contexts, or two or more components can combine to form other useful tools. They also point to the human body, which ID proponents regard as God's most perfect creation, noting that while humans are the most cognitively advanced species in modern times, the human body is also an imperfect work in progress. To accommodate bipedal motion and a large brain, certain design compromises were necessary, resulting in ailments such as slipped discs, weak knees, arthritis, neck and back pain, and hemorrhoids.

Evolutionists draw on the analogy of a canal versus a river. A canal fits the scheme of Intelligent Design — it is a receptacle for water built by humans for storage and transportation. A river, by contrast, was not built for a specific purpose, yet it performs its own functions, even though its course is best described as meandering. William Dembski, a mathematician and one of the originators of Intelligent Design theory (Dembski 1999), proposed the concept of "specified complexity." Human beings, he argued, are specifically complex, and whenever complexity is both specific and reproducible within a species, it is the result of design rather than natural selection. Mathematicians have since demonstrated that Dembski's arguments rest on faulty mathematics, flawed statistics, and basic misrepresentations.

A further critique of Intelligent Design is that its proponents largely ignore available fossil evidence, carbon dating that places species in chronological sequence, and DNA evidence that links species to one another. A prominent example of the latter is the well-documented similarity between human and chimpanzee genomes.

The issue of Intelligent Design is deeply controversial. The framing of creationism within a scientific construct means it can enter the educational process, raising the question of whether it should be taught in schools as a replacement for evolution or as an equally acceptable alternative theory.