Scientific controversy vs. social controversy

In the first few pages, Explore Evolution misidentifies social controversy as scientific dispute, misdefines basic terminology, misrepresents scientists, and misunderstands pedagogical principles. The book’s religious agenda is misleadingly obscured. Papers and government policies are presented out of context and thus likely to be misunderstood. These errors are smoothly woven together like a conjurer’s words, misdirecting the reader from the mundane mechanics going on up the authors’ sleeves.

These errors are not random; they are all essential to sustain the premise of the book which is that under the guise of “critical thinking”, students should be encouraged to embrace creationist criticisms of evolution as valid science, and thus reject evolution in favor of intelligent design or some other form of creationism. That premise justifies the authors’ presentation of supposed “critics” of evolution, the identities and agendas of whom are masked. Under the guise of “presenting all sides”, the authors instead present information rejected by the scientific mainstream, obscuring from students the fact that ongoing research into evolution is scientifically uncontroversial. Current research and scientific debate focuses not on whether evolution happens and can explain the diversity of life, but which evolutionary mechanisms have dominated. Students reading Explore Evolution will not understand this key fact, and will be ill-prepared for more advanced science classes.

"Controversy" over evolution

Summary of problems:

Evolution is as well-established as a scientific theory can be. While scientists continue to investigate the importance of different mechanisms involved in evolution, the scientific community agrees that the descent with modification of living things -- the big idea of biological evolution -- accounts for the diversity of life on earth today. To claim or imply otherwise is simply wrong, and miseducates students about a critically important scientific idea.

Full discussion:

…the theory of evolution remains the focus of intense public controversy.
Explore Evolution , p. v
Indeed, the public debate over evolution waxes and wanes and takes various forums, and often is conducted with considerable heat. However, a few sentences later, the book refers to alleged “real (and more interesting) scientific controversies about evolution” (p. v, emphasis added). This implies the existence of a scientific controversy which does not exist.

In reality, evolutionary theory, the common ancestry of living things, is the core, fundamental, unifying construct of the life sciences. In the biomedical sciences, it has been a highly productive and powerful explanatory framework for research over the past five decades. In the last 10 years, the explosion of data in genomics and new insights in developmental biology have given evolutionary theory an even higher prominence and greater importance than it enjoyed before. It is for these reasons that the National Academy of Sciences recently wrote:

Biological evolution is the central organizing principle of modern biology.

The study of biological evolution has transformed our understanding of life on this planet. Evolution provides a scientific explanation for why there are so many different kinds of organisms on Earth and how all organisms on this planet are part of an evolutionary lineage. It demonstrates why some organisms that look quite different are in fact related, while other organisms that may look similar are only distantly related. It accounts for the appearance of humans on Earth and reveals our species’ biological connections with other living things. It details how different groups of humans are related to each other and how we acquired many of our traits. It enables the development of effective new ways to protect ourselves against constantly evolving bacteria and viruses.
National Academy of Sciences and Institute of Medicine of the National Academies (2008) Science, Evolution, and Creationism. Washington, DC:The National Academies Press

Evolution, climate change, plate tectonics, and string theory

Summary of problems:

Explore Evolution equates alleged controversy about evolution with controversies over plate tectonics, climate change, and string theory. This elevates social and political controversies to the same level as scientific controversy. Whether evolution takes place and explains the diversity of life is no longer scientifically controversial; the remaining controversy derives from political and cultural concerns.

String theory is currently scientifically controversial, just as plate tectonics was controversial until the 1960s, and global warming was scientifically controversial until the late 1990s. Evolution was last scientifically controversial in the 19th century and that controversy ended by the 1870s. By that date, essentially all practicing scientists accepted that natural causes could account for the formation of new species and that all living things share a common ancestry.

Full discussion:

Explore Evolution describes these supposed controversies in this passage from the Preface:
Controversies in science are nothing new. As recently as the early 1960s, for example, most geologists accepted the “geosynclinal theory” as the explanation of how mountain ranges form. After a significant period of controversy, most scientists came to accept the theory of plate tectonics because it provided a better explanation for a larger number of scientific observations. Yet without understanding the arguments that led to the acceptance of plate tectonics, it is very difficult to understand the theory itself or its current standing in the scientific community.

Today we continue to have important unresolved scientific controversies in many branches of science. In climatology, for example, scientists disagree over what global warming is, whether it is a natural phenomenon or a man-made problem, how big a problem it presents, and what (if anything) should be done about it. In theoretical physics, scientists disagree over the meaning and importance of string theory.
Explore Evolution, p. vi

This passage conflates scientific controversies with social controversies, an error that runs throughout Explore Evolution. In general, theories are scientifically controversial until they can provide testable and well-tested explanations for phenomena. By that standard, string theory is currently controversial, but global warming and plate tectonics are not scientifically controversial today. Despite the cessation of scientific controversy over evolution or global warming, both concepts continue to generate social controversy over their implications for policy or for personally-held religious views.

String theory provides a powerful theoretical model for unifying our understanding of various physical forces. On the other hand, it has yet to yield testable predictions that can be measured on current equipment in a way that distinguishes them from results generated using the existing 'standard' theory (see Smolin [2006], The Trouble with Physics, for an excellent review of these problems). It is therefore unknown whether the novel aspects of string theory are correct. String theory may be right; it may be a dead end; science simply does not know yet. Improvements in our scientific instruments may someday allow physicists to validate or disprove string theory. At that time, some or most of the controversy over its validity will die down and physicists will shift to debates over details of string theory rather than to debates over its scientific status per se. Pangaea and Fossil Distribution: from United States Geological SurveyPangaea and Fossil Distribution: from United States Geological Survey

This scientific process for examining ideas was used for the now-accepted explanations plate tectonics, evolution, and global warming. When Alfred Wegener proposed that the seeming lock and key fit of the coastlines of South America and Africa could be explained by moving continents, he backed his proposal with significant paleontological evidence, but could not explain the mechanisms involved in continental movement. Later research showed evidence of new crust forming as molten rock rose from deep sea rifts, including one midway between the African and South American coasts. Geologists developed a model in which plates are pushed together and pulled apart, creating new crust and destroying old crust, and found that it explained not only the evidence Wegener provided, but other questions about the formation of mountain ranges and the occurrences of volcanoes and large earthquakes.

Once Wegener’s idea had a testable model and a literal mountain of supporting evidence, it was rapidly accepted by geologists and ceased to be controversial. It should be noted that, contrary to Explore Evolution’s claim, students have no trouble understanding plate tectonics without first learning about discredited ideas that preceded it.

In fact, a similar process took place in the 19th and early 20th centuries as scientists addressed Darwin and Wallace’s evolutionary ideas. The idea of common ancestry of living things was rather quickly accepted in the scientific community; Darwin's choice for the most important mechanism of evolution, natural selection, was slower to be accepted. A major problem was the lack of a mechanism for new variation to be replenished each generation after natural selection had whittled out the survivors, a problem that could be solved only with a clearer understanding of how characteristics were passed down from generation to generation. Critics rightly objected to the model of inheritance Darwin proposed in the Origin of Species, which involved simply averaging parental characteristics. Of course, none of Darwin's contemporaries understood how heredity worked either: it wasn't until the rediscovery of Mendelian genetics in the early 20th century that an accurate basis for inheritance became available.

Mendelian genetics resolved a key scientific controversy that surrounded natural selection, much as sea-floor spreading resolved a key scientific controversy about continental drift. As scientists integrated their new understanding of genetics with the existing evolutionary ideas, they produced a more comprehensive picture of evolutionary biology, often referred to as the Modern Synthesis. But during the debate about the validity of natural selection and the development of the Modern Synthesis, scientists were not seriously questioning whether evolution occurred or whether universal common descent was the most reasonable inference from the data. Those scientific questions had been resolved decades earlier.

More recently, climate scientists went through a similar transition regarding global climate change. The idea that adding carbon dioxide to the atmosphere might cause global warming was first proposed in 1896 by Svante Arrhenius. Until modern supercomputers, it was impossible to fully model the global climate or to predict the consequences of human interactions with the atmosphere. Without modern satellites and high-altitude measurements, it was impossible to test those models. When weather stations demonstrated a global trend of rising temperatures in the 1980s and 1990s, some scientists attributed that change to the rise in atmospheric carbon dioxide measured globally, while others felt that the models available at the time were not accurate enough, and that the natural variability of the climate was too large relative to measured temperature changes to require anything but a natural explanation. In 1990, scientists with the non-partisan Intergovernmental Panel on Climate Change (IPCC) agreed that “there is a natural greenhouse effect,” that “emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases.” At the time, they concluded that “global mean surface air temperature has increased by 0.3 to 0.6° C over the last 100 years. The size of this warming is broadly consistent with predictions of climate models, but it is also of the same magnitude as natural climate variability. Thus the observed increase could be largely due to this natural variability; alternatively this variability and other human factors could have offset a still larger human-induced greenhouse warming. The unequivocal detection of the enhanced greenhouse effect is not likely for a decade or more.”

However, by 1995, the IPCC report found that “The balance of evidence suggests a discernible human influence on global climate,” observing that “[s]ince the 1990 IPCC Report, considerable progress has been made in attempts to distinguish between natural and anthropogenic influences on climate.” In 2001, the IPCC's Third Assessment Report found “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities,” and concluded that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.” In IPCC reports, “likely” means that the scientists assess the likelihood of the statement being true at between 66-90% chance, while the 1995 statement about the “balance of evidence” refers to a chance slightly higher than 50%. When the IPCC released its Fourth Assessment Report in 2007, the team of climate scientists concluded that “[w]arming of the climate system is unequivocal,” and that “[m]ost of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations." “Very likely” means better than 90% chance.

Between the third and fourth reports, a researcher on the sociology of science demonstrated the growth of a scientific consensus behind anthropogenic climate change. Dr. Naomi Oreskes published a paper in the December 3, 2004 issue of Science surveying publications about climate change between 1993 and 2003. Oreskes classified those papers as either accepting the 2001 consensus that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations," rejecting that statement, or taking no position on it. Of 928 papers identified in scientific databases which contained the phrase “global climate change,” 75% supported the IPCC consensus, 25% did not discuss it, and none explicitly rejected it. While such papers may exist, it is clear that there was not a vociferous debate between scientists in the field over whether humans are causing global warming. That consensus can also be demonstrated by statements from major scientific bodies, including the National Academies of Science, the American Meteorological Society, the American Geophysical Union, and the American Association for the Advancement of Science, all essentially restating the IPCC assessment.

This is not to say that debate in any of these fields has ended. Just as geologists continue to make new discoveries about plate tectonics, and to debate those discoveries with intensity, evolutionary biologists continue to debate the relative influence of the various forces driving evolution, and climate scientists continue to disagree about the precise implications of current human activities for the future of Earth's climate. The era of controversy ends when the scientific community comes to accept that a particular theory is testable and offers superior explanations for known phenomena.

The era of controversy ended for evolution decades ago, and Explore Evolution's claims to the contrary are disingenuous. The current controversy surrounding evolution is not a scientific controversy. The comparison to global warming is instructive. Global warming is scientifically uncontroversial, but the question of whether society ought to make some effort to avert it, and what should be done in that event, are subject to intense disagreement. Thus, global warming is scientifically uncontroversial, but generates controversy because of its policy implications. Similarly, evolution is not scientifically controversial, but does generate social controversy because of people's disagreements about its philosophical, religious and metaphysical implications. Those controversies cannot be resolved based on empirical scientific evidence alone.

"Key aspects" of evolution

Summary of problems:

Explore Evolution asserts that "this book will help you understand … why many scientists find [contemporary Darwinian theory] persuasive, and why other scientists question key aspects of it" (p. v). The supposedly "key aspects" or "key claims" which Explore Evolution targets are issues that are not scientifically controversial, yet are persistent targets of creationist attack. Biologists have reached a strong consensus about the validity of universal common descent, the power of natural selection, and the importance of studying fossils, embryology, biogeography, homologous structures, etc. There is ongoing research and disagreements concerning the details in all these areas. However, Explore Evolution implies that any controversy or disagreements within evolutionary biology casts doubt on the underlying validity of the theory of evolution. This is a classic creationist falsehood.

Full discussion:

The preface states

We hope this book will help you understand what contemporary Darwinian theory is, why many scientists find it persuasive, and why other scientists question key aspects of it.
Explore Evolution, preface

If we assume that this statement is referring to scientists in fields with some relevance to evolutionary theory (e.g. biologists, geologists, anthropologists etc.), this statement cannot be supported. Nearly every relevant national and international scientific organization has taken a position in favor of the basics of evolutionary theory, and in opposition to creationism and intelligent design. This February 2006 statement from the American Association for the Advancement of Science, the largest general scientific society in the world (serving 262 affiliated scientific societies and academies, with over 10 million members), is only one example of many.

Evolution is one of the most robust and widely accepted principles of modern science. It is the foundation for research in a wide array of scientific fields and, accordingly, a core element in science education. The AAAS Board of Directors is deeply concerned, therefore, about legislation and policies recently introduced in a number of states and localities that would undermine the teaching of evolution and deprive students of the education they need to be informed and productive citizens in an increasingly technological, global community. Although their language and strategy differ, all of these proposals, if passed, would weaken science education. The AAAS Board of Directors strongly opposes these attacks on the integrity of science and science education. They threaten not just the teaching of evolution, but students' understanding of the biological, physical, and geological sciences.

Some bills seek to discredit evolution by emphasizing so-called "flaws" in the theory of evolution or "disagreements" within the scientific community. Others insist that teachers have absolute freedom within their classrooms and cannot be disciplined for teaching non-scientific "alternatives" to evolution. A number of bills require that students be taught to "critically analyze" evolution or to understand "the controversy." But there is no significant controversy within the scientific community about the validity of the theory of evolution. The current controversy surrounding the teaching of evolution is not a scientific one.

In contrast, the Discovery Institute lists only 700 scientists on their Dissent from Darwin statement. No scientific societies have signed on to that statement. Many of the signers do not have degrees or research interests in relevant scientific disciplines. Not surprisingly, the Dissent from Darwin list has many names of engineers and computer scientists, whose everyday work does not bring them in contact with modern evolutionary theory. This number of dissenters, even if they were all working in a relevant scientific field, is certainly small when compared to the hundreds of thousands of scientists affiliated with the scientific societies which have passed statements or resolutions supporting modern evolutionary theory. It is even small compared to the number of graduate students in science and engineering disciplines. According to the National Science Foundation, institutions of higher education in the USA alone produce over 20,000 doctoral graduates in science and engineering annually.

So while it is certainly true that "some scientists" question evolution, hardly any working scientists in the relevant disciplines find it to be controversial, and no relevant scientific society finds it to be controversial. The perception left by this statement in Explore Evolution is completely wrong.

It would fair to say that there are debates and controversies within evolutionary biology over questions such as the relative importance of natural selection and neutral mutations to evolutionary change, the role of symbiosis, or the nature of large-scale patterns of evolutionary change. These questions, though, are not the discussed in Explore Evolution. The supposedly "key aspects" of the theory which Explore Evolutionclaims to present "both sides" of are, in fact, simply repetitions of long-discredited creationist claims, as will be shown throughout this critique.


Ronald Numbers, The Creationists, pp.__

Bowler, The Non-Darwinian Revolution, pp.__

Matzke and Gross in Scott and Branch, NIOC.

S. Sarkar, Doubting Darwin? Creationist Designs on Evolution, Blackwell, 2007, pp. 163-166