Giberson and Collins, in their first chapter, propose a set of three simple, interlinked propositions defining evolution as a formal theory. It is worthwhile to review basic evolutionary theory. Following are verbatim quotes: (1) All current species have descended from common ancestors (2) Changes in species occur gradually over time as a consequence of mutations (3) Species change when beneficial mutations allow certain of them to have more offspring than others.
The authors then set forth a familiar, classic example of evolution in action. They cite an example of “artificial selection”--man’s long history of selectively breeding many different varieties of dogs in order to bring out various desired traits. Their account exemplifies what is theorized to happen by chance in nature without any input from man. Such changes occurring in nature are termed “natural selection.” In theory this selection process slowly brings about changes such as those accomplished over time by deliberate selective breeding of dogs. In nature over the long term, a new species is produced, according to the theory. Production of a new species is called macroevolution.
Use of dog breeding as supporting evidence for evolution is mystifying. There is a surprising omission in the citation of selective dog breeding by Giberson and Collins. The authors are impressed with the difference between a dachshund and a Great Dane, but at the end of the day, they remind us, they are still both dogs. The authors do not remind us that left to themselves over several generations, without heroic breeding efforts the dogs will slowly return to their original appearance. In other words, no macroevolution occurs.
The following quote (p. 45) is reproduced in its entirety because it is significant to their primary case:
There is a natural commonsense intuition that species are, on average, stable and unlikely to evolve into a new species. So, while small, microevolutionary changes certainly occur, there seems to be little evidence for large-scale, macroevolutionary changes. Scientists, however, make the confident claim that macroevolution is simply microevolution writ large: add up enough small changes and we get a large change. So what is really going on here?
The important, appropriate, and entirely reasonable question to ask is, Does the uncontroversial fact of microevolution provide evidence for the complex and controversial claims of macroevolution? In fact, we believe this particular question is really at the heart of the entire controversy over evolution.
We begin our response by noting that the distinction between micro and macro evolution is arbitrary. Every step along an evolutionary pathway is, in fact, a tiny, micro evolutionary change…
In other passages we read a few paragraphs under headings “Proof that Evolution has Occurred” and “Proof of Macroevolution?” These passages refer to the commonality of DNA sequences across various species of living things, especially genes purported to be “broken.” The “genes that are broken” reference is reminiscent of an idea evolutionists frequently used a few years ago to disparage ideas of creation and intelligent design--so-called “junk DNA”--leftovers from common ancestors. This term is not used even once in The Language of Science and Faith, because many non-coding sequences and other features of DNA whose functions were previously unknown are now known to have function. Therefore, some of the best evidence formerly cited as evidence for evolution has now been demonstrated not to be persuasive evidence.
The science supporting evolution is outlined in a brief 23 pages and is summarized above. The remaining chapters deal with other topics and read like an inspirational philosophical and spiritual pep-talk. I found some of the conversation useful. But if I were searching for an answer to the question, “Is Evolution True?” I would be unconvinced. If I were inclined to be receptive to the need to get on board with science, BioLogos-style, I might be impressed. To be fair, I realize this volume was not meant to offer exhaustive evidence.
The process of arriving at a scientific answer is enormously complex. Generally, this is not a weakness of science, but rather, a strength. The multidimensional complexity inherent in the process of science discovery also offers multidimensional opportunities for errant conclusions. By the admission of scientists, science is a subjective enterprise. Science is not an entity of truth in itself, but it helps us to discover truth. The question we should ask ourselves as we read multiple volumes on the important topic of origins is not, “Am I on board with science?” Instead, we should ask, “Am I on board with truth?”