Trifid Nebula NGC6514 [Courtesy NASA]

Are there controversies among scientists?

David H. Bailey
Updated 26 March 2022 (c) 2022


Some creationist and intelligent design writers claim that old-early geology and evolution remain controversial among scientists, or, in other words, that a significant minority of scientists dissent from the theories.

Other writers claim that scientists have conspired to keep from the public eye some important evidence undermining evolution (or other theories in the science-religion arena), or, at the least, that there is some "group-think" phenomenon going on, wherein scientists are reluctant to publish material that would draw these established theories into question. As a single example, the 2008 movie "Expelled" claimed that creationist and intelligent design writers have been systematically shut out from scientific journals and conferences, due to a "conspiracy" among the scientific establishment. In a similar vein, Philip Skell, a retired chemistry professor at Pennsylvania State University recently wrote that an unquestioning acceptance of Darwinism has persisted in the field of biology "mainly because too many scientists were afraid to challenge what had become a philosophical orthodoxy among their colleagues" [Skell2005].

How do scientists respond to these claims? Are the basic notions of old-earth geology, evolution and big bang cosmology really considered "controversial" among scientists? Is there a "conspiracy" to hide the "truth"?

Is there "controversy" on basic old-earth geology, evolution and the big bang?

It is most certainly not true that there is any level of "controversy" regarding the basic principles of old-earth geology and biological evolution. Modern radiometric dating, which has been developed and refined over several decades, produces very consistent and reliable dates for the various epochs of Earth's development (typically many millions of years) and thus overwhelmingly contradicts the notion that the earth was created a few thousand years ago. See Radiometric dating for additional details.

For similar reasons, evolution, at this point in time, is much more than a "theory" in the colloquial sense of the word. The basic notion of evolution, namely that life began on Earth more than three billion years ago and has been evolving and elaborating since then, has been confirmed in hundreds of thousands of exacting studies, even as some of the actual branching and mechanisms continue to be investigated. Indeed, the latest DNA sequence data screams "common descent" -- there is no other reasonable way to interpret these results (see DNA and Evolution for additional details).

Also, the basic notion that the universe we reside in began approximately in an explosive burst 13.8 billion years ago and has been expanding and evolving since then, with matter coalescing into stars and galaxies over the eons, leading to an environment conducive for biological development on Earth, is hardly in doubt, even as the actual details and mechanisms of exactly how this happens continue to be investigated -- see Big bang.

Finally, claims that large numbers of scientists question the basics of evolution or cosmology are simply false. For example, more than 99% of all qualified professional scientists in these fields agree with the fundamental precepts of evolution -- see Scientists-evolution.

Real controversies in scientific research

Once one ventures from the basics of well-established theories, such as evolution and big bang cosmology, controversies do appear. In fact, claims of "conspiracy" or "group-think" among scientists are utterly countered by the numerous examples of real controversies that have erupted among scientists in the past few years. How can a "conspiracy" possibly be maintained within a community whose members so clearly express disagreements with others in their community?

Here are just a few examples of the many true controversies that could be mentioned, some of them quite heated:

  1. The "hobbit" fossils

    One of the best examples of public scientific controversy arose from the 2004 discovery of Homo floresiensis, more commonly known as the "hobbit" due to its diminutive size, on the island of Flores in the Indian Ocean north of Australia. Remarkably, this specimen lived until as recently as 66,000 years ago [Brown2004; Wade2004]. The discoverers pointed out that the fossil combined an unusual mix of human and early hominid features, including a nearly complete skull that most resembled Homo erectus, but with legs more akin to Australopithecines. The authors theorized that the specimen represented a distinct species of hominins, and its diminutive size was due to an effect known as "island dwarfism" (the evolutionary reduction in size of a species confined to an island or other domain with limited resources).

    A heated and rather public controversy ensued [Krause2009]. The initial salvo was from biologists Maciej Hennenberg and Alan Thorne, who dismissed the notion of a separate species, saying that the small skull instead represented merely a case of microcephaly, a malady that causes dwarfism in afflicted humans. In response, Brown and Morwood acerbically described Henneberg and Thorne's article as "an extremely poorly informed, and ill designed, piece of 'research'." The microcephaly explanation was then boosted by a paper published by Indonesian researcher Teuku Jacob in the prestigious National Academy of Science, after a detailed comparison of the hobbit bones with the skeletal features of regional humans. What's more, Robert Martin of the Field Museum of Natural History in Chicago published a paper drawing into question the initial claim that the Hobbits had descended from Homo erectus. But then Dean Falk, a leading expert on hominid brain evolution at Florida State University, found that although the Flores find was most similar to that of Homo erectus and was least similar, among the various candidates, to microcephalic humans.

    Subsequently additional hobbit skeletons were found, casting more doubt on the microcephaly alternative explanation. Critics of the new species designation have asserted that there are numerous other pathologies that need to be examined. For example, a 2010 study noted similarities between anatomical features of the Flores specimens and persons afflicted with hypothyroid cretinism (iodine deficiency). Numerous other studies have been done, with researchers aligning on one side of the debate or the other [Oxnard2010; Callaway2009; NS2010; Kaplan2011; Pacchioli2014].

    In November 2015, Japanese researchers found, after a thorough analysis of hobbit teeth, that the specimens had numerous dental traits not typical of any human (or any other known hominin), but relatively close to those of Homo erectus [Choi2015]. This was followed in April 2016 by a team led by Canadian paleoanthropologist Matthew Tocheri, who found, by carefully dating ash in the cave and the hobbit fossils themselves, that the hobbits lived from 66,000 to 87,000 years ago, not 18,000 as originally claimed, which rules out the possibility that these are human (since humans did not arrive on the island until 50,000 years ago) [Gramling2016]. In June 2016, Australian researchers announced the discovery of additional Homo floresiensis fossils, some as old as 700,000 years [Zimmer2016a]. Finally, in April 2017, in the most comprehensive study to date, researchers concluded that the hobbits were a distinct hominin lineage, most likely not likely descended from Homo erectus as earlier believed, but descended from a lineage that left Africa roughly 1.75 million years ago [SD2017a].

    In short, while some researchers are still unconvinced, the tide is turning strongly to the original hypothesis that the hobbits are a separate hominin species.

  2. The death of the dinosaurs

    We have all heard how a large asteroid impact caused the end of the dinosaurs approximately 66 million years ago. Actually, the picture is not so simple. One group of scientists, led by Luis Alvarez (the recipient of the 1968 Nobel Prize in physics) and his son Walter Alvarez), indeed argues that the dinosaurs were destroyed in the wake of a large asteroid that landed near Chicxuluub, Mexico. Princeton geologist Gerta Keller, however, argues that enormous floods of lava seen in India at that time are evidence for a major period of volcanism, which would have spawned an environmental catastrophe of poisonous volcanic gases, global warming, acid rain and acidifying oceans. This controversy is discussed in a January 2015 New York Times article by Peter Brannen [Brannen2015].
  3. The Ardi and A. sediba fossils

    Another good example of public controversy in the area of human evolution was seen in 2009,when a team of researchers led by famed anthropologist Tim White of U.C. Berkeley published their finding of a rather complete fossil skeleton named Ardipithecus ramidus, or Ardi, which was dated to 4.4 million years ago. This is more than one million years older than Lucy, the famous skeleton of the species Australopithecus afarensis [Wilford2009]. White's team concluded that the skeleton was likely in the path that led to modern humans. However, in May 2010, a team led by Thure Cerling of the University of Utah published a study questioning this conclusion, noting that an analysis of soils and silica in the area surrounding the find indicated a tree-savana or bush-savana environment (and thus not a likely habitat for hominins) [Wilford2010]. White's team testily replied that the Cerling team ignored "the totality of the fossil, geological and geochemical evidence" presented it the original papers, including the abundant presence of fossilized mammals adapted to wooded life. This fact, according to White, established that Ardi lived in "closed habitats," not in open savanna and thus was plausibly a human ancestor [Wilford2010]. In February 2011, Terry Harrison of the Center for the Study of Human origins at New York University and some other researchers again questioned whether Ardi is a human ancestor, saying that this species may have split off from the main branch of ancient apes before the last common ancestor linking humans and chimps. In response, Tim White called the Harrison team's article a "six page illustrated op-ed piece" [Harmon2011].

    A closely related controversy is the status of a newly discovered species known as Australopithecus sediba (or A. sediba, for short), which was discovered by Lee Berger and his nine-year-old son Matthew in 2008. These fossils, which have been dated as between 1.977 and 1.980 million years ago, are also thought to be the true ancestors of Homo sapiens by some. This is based on findings such as its hands, which are more humanlike than that of Homo habilis, which other scientists believe was the proper ancestor. These controversies are summarized in a nicely written feature article in the April 2012 Scientific American [Wong2012]. This controversy re-erupted in 2014, when researchers at Tel Aviv University argued that the Australopithecus sediba fossils are, in fact, from two different hominin species, but the original discoverers of the fossils are not convinced [Wong2014a].

  4. Dating the oldest rocks

    In March 2014, a disagreement over the age of some of the oldest rock specimens on the planet, unearthed along the northeastern edge of Hudson Bay in Canada, came to the public view with a feature article in Scientific American [Zimmer2014b]. One group, led by Jonathan O'Neil of the University of Ottawa, concluded a series of studies by claiming that selected specimens there are 4.4 billion years old, and thus constitute the oldest rocks on the planet and a unique potential window into life at the earliest epoch in the earth's history. But another team, led by Stephen Mojzsis, and utilizing a somewhat different technique, determined that the specimens are "only" 3.75 billion years old. At some scientific conferences, Mojzsis and his colleagues have presented their results in the same sessions that O'Neil and his team have presented theirs. Neither team is giving ground for the time being, and additional studies are slated to resolve the discrepancy [Zimmer2014b].
  5. Geneticists versus archaeologists

    Another disagreement has been brewing between a group of geneticists researching early humans, and some archaeologists (actually paleoanthropologists) studying the same era, namely from about 200,000 years ago, when many believe the first fully modern humans appeared, to roughly 30,000 years ago, when all remaining "archaic" humans, such as Neanderthals, disappeared. Archaeologists argue, based on available fossil evidence, that all archaic species of humans disappeared in Africa by 200,000, with those remaining living in Europe or elsewhere. But in July 2012, a team of geneticists, led by Joseph Lachance and Sara Tishkoff of the University of Pennsylvania, published a study, based on a full genome sequence of 15 individuals from native tribes in Africa, arguing that some previously undiscovered species coexisted and occasionally interbred with humans in Africa until as recently as 25,000 years ago. Archaeologist Richard Klein of Stanford University derided the geneticists' results as "a further example of the tendency for geneticists to ignore fossil and archaeological evidence, perhaps because they think it can always be molded to fit the genetics after the fact." But the geneticists are holding firm. Co-author Joshua Askey insisted that they are "reasonably confident that what we are seeing in Africa does represent archaic introgression" [Wade2012a].
  6. Arsenic-based life

    In December 2010, a team of NASA-funded researchers led by Felisa Wolfe-Simon, a young astrobiologist, startled the scientific world with an announcement that they had coaxed a species of bacteria originally found on the shores of Mono Lake in California to utilize arsenic as a substitute for phosphorus, one of the six primary elements of all known life on earth. Cultured in an laboratory environment starved of phosphorus but with plenty of arsenic, generation after generation the bacteria colony substituted more arsenic into its biological processes, until experiments showed that arsenic had even been incorporated into the organism's DNA [Overbye2010a]. But the Wolfe-Simon paper quickly generated significant controversy, with some scientists questioning whether the NASA team's conclusions were justified based on their experimental results [Hayden2012]. Rosie Redfield, a zoologist at the University of British Columbia, in a blog posted shortly after the announcement, called the NASA team's analysis "shameful" and concluded, "If this data was presented by a PhD student at their committee meeting, I'd send them back to the bench to do more cleanup and controls." [Redfield2010]. Steven Benner, an astrobiologist at the Foundation for Applied Molecular Evolution in Gainesville, Florida, noted that because these researchers challenged well-established knowledge about biochemistry, their burden of proof was very high. Paraphrasing Carl Sagan, he said, "This is an exceptional claim, and exceptional claims require exceptional proof." [Brown2010]. The current consensus is that the original arsenic finding was in error, although Wolfe-Simon herself has not yet conceded [Kaufman2012].
  7. Human arrival in Western Hemisphere

    For many years, the prevailing wisdom in the field of Western Hemisphere archaeology was that humans first arrived in the Americas approximately 13,000 years ago (11,000 BCE) across the Bering Strait from Asia. For example, the radiocarbon dating of spear points found near Clovis, New Mexico indicated that a big-game hunting group arrived arrived approximately 13,000 years ago.

    But recent findings have challenged this belief. In 2011 archaeologists announced that humans had reached the "Buttermilk Creek" site in Texas as early as 15,000 years ago [Wilford2011]. In 2012 archaeologists found some human artifacts in the Paisley Caves of Oregon that were independently dated to be as old as 14,500 years ago [Kaufman2012]. And in March 2013, archaeologists analyzing a site in Uruguay found remains, dated to 30,000 ago, indicating that humans were hunting giant sloths there at the time [Thompson2013]. Archaeologist Niede Guidon argues that humans arrived in South America 48,000 years ago, and perhaps even earlier [Romero2014].

    These disputes came to a head in March, 2014, when a team of archaeologists found human drawings and human tools at a site in Brazil that has been dated to 22,000 years ago, fully 10,000 years before Clovis hunters appeared in North America [Romero2014]. Eric Boeda, a French archaeologist leading the excavations there, exulted, "The Clovis paradigm is finally buried." Still, others dispute the findings. Gary Haynes, an archaeologist at the University of Nevada, argued that perhaps the stones found there were not tools made by humans, but instead were chipped and broken by rockfall. Stuart Fiedel argued that monkeys might have made the tools instead of humans. But these dismissals have produced equally strong responses from other researchers. Vanderbilt archaeologist Tom Dillehay chimed back, "Riedel does not know what he is talking about," noting that the tools found at the site are similar to tools found at a site in Chile [Romero2014]. Additional research is planned by several teams to resolve the controversy.

  8. Group selection

    One other example worth mentioning in the evolutionary biology arena is the recent public spat over the theory of altruistic behavior that has been devised to explain the evolution of complex social systems such as those seen in ants, bees and humans. The "inclusive fitness theory," which originated with William Hamilton in 1964, hypothesizes that altruistic behavior, such as a worker bee caring for the offspring of a queen (rather than producing and caring for its own offspring), can arise when the worker is closely related to the queen. In August 2010, the eminent biologist Edward O. Wilson teamed with mathematical biologists Martin Nowak and Corina Tarnita to argue that it was not necessary to invoke Hamilton's theory to explain this behavior, and proposed a "group selection" theory instead. Several leading scientists quickly criticized the Wilson-Nowak-Tarnita paper. These criticisms came to a head in March 2011 with an open letter signed by nearly 150 evolutionary biologists, published in the prestigious journal Nature. In spite of these criticisms, Wilson, Nowak and Tarnita remain unmoved. Nowak, for instance, regards this and other such letters as "the reactions of people who are clinging to an obsolete theory" [Pennisi2011].

    In 2012, this controversy erupted again with the publication of Wilson's book The Social Conqueset of Earth, which promoted group selection in human evolution and culture. In a review, biologist British Richard Dawkins blasted the book as having "a slew of mistakes" [Dawkins2012]. Wilson responded, "If science depended on rhetoric and polls, we would still be burning objects with phlogiston [a mythical fire-like element] and navigating with geocentric maps" [Thorpe2012]. Evolutionary psychologist Steven Pinker weighed in by declaring that "the more carefully you think about group selection the less sense it makes, and the more poorly it fits the facts of human psychology and history" [Pinker2012]. Martin Nowak then defended group selection in a Scientific American article [Nowak2012]. The continuing controversy, with a summary of the arguments on both sides, is summarized in a July 2012 Scientific American commentary [Johnson2012].

  9. Speed-of-light controversy

    Controversies also are commonplace in the world of physics, where experiments involving state-of-the-art equipment sometimes give contradictory results until additional work clarifies the competing claims. Perhaps the best-known example was the September 2011 announcement that scientists conducting an experiment at the Gran Sasso laboratory in Italy (an experimental facility under the Italian Alps), had measured neutrinos traveling at faster than the speed of light, which would contradict Einstein's special theory of relativity [Overbye2011b]. In the wake of this finding, some physicists proposed theoretical frameworks where such a phenomenon might be plausible, but others were unconvinced and insisted that there must be a flaw in the experimental measurements. Finally, in March 2012, the matter was settled when the original research team announced that they had found a problem with a cable connecting to a GPS receiver that might explain the discrepancy. Shortly thereafter another team of researchers, who share the same underground laboratory, announced their finding that precisely confirmed Einstein's theory. Thus while the earlier announcement caused considerable sensation for a few months, in the end the matter was resolved by more careful experimental methods [Overbye2011b].
  10. Big bang inflation

    While the overall history of the universe since the big bang is hardly in doubt, questions remain regarding a key process of the big bang known as "inflation." While inflation made sense according to the original mathematical formulation of the inflation process developed back in the 1970s and 1980s, it seems significantly less satisfactory today, and even some leading figures in the field now believe that this scenario needs to be rethought. More modern mathematical formulations have many "ad hoc" parameters and assumptions, many of which are increasingly dubious, or which, as with considerations of the "multiverse," must invoke the anthropic principle to explain the early evolution our universe. For example, highly improbable conditions are required for the inflation process to be initiated. Worse, it appears that the most natural course of events is for the inflation process to continue indefinitely, producing an infinite variety of outcomes, so that it is difficult to make any firm observational predictions from the theory.

    These difficulties had led even long-time supporters of inflation to question the theory's viability. Paul Steinhardt of Princeton University is one vocal detractor. In 2012 he declared, "We thought that inflation predicted a smooth, flat universe. Instead, it predicts every possibility an infinite number of times. We're back to square one." Similarly, Sean Carroll, a CalTech cosmologist, explains, "Inflation is still the dominant paradigm, but we've become a lot less convinced that it's obviously true. ... If you pick a universe out of a hat, it's not going to be one that starts with inflation." [Steinhardt2011; Gefter2012; Ijjas2017; Moskowitz2014]. See Big bang and Inflation for more details.

  11. LIGO detection of gravitational waves

    In a historic announcement in February 2016, an international team of researchers who developed and operate the the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment (a pair of large L-shaped devices, one in Livingston, Lousiana and the other in Hanford, Washington) reported detecting the gravitational waves of two black holes colliding, as predicted by Einstein's general theory of relativity. The physicists who conceived and led the development of the project were awarded the 2017 Nobel Prize in physics.

    But recently a group of physicists at the Niels Bohr Institute in Denmark published a paper casting doubt on these discoveries, claiming that they had found unexplained correlations in the noise produced by the detectors [Wolchover2018]. Two independent groups of researchers then embarked on a review of these results. They concluded their analyses by stating that the detections still stand: "We see no justification for lingering doubts about the discovery of gravitational waves," as one group's led by John Moffat of the Perimeter Institute for Theoretical Physics declared. But Andrew Jackson, who led the Copenhagen-based group that questioned the detection, called one of the exonerating reports "absolute rubbish," and also dismissed the findings of the second report. In response, Moffat wrote "The Copenhagen group refuse to accept that they may be wrong. ... In fact, they are wrong." [Wolchover2018]. Meanwhile, the LIGO team has announced new numerous new detections. So although most researchers are convinced that these detections are real, it is clear that the debate will continue for a while.

  12. String theory and the multiverse

    Another major arena of controversy in physics and cosmology centers on string theory and the recently hypothesized "multiverse." Since the 1970s, string theorists been exploring the notion that all physical phenomena are, at the lowest level of reality, tiny vibrating strings and membranes vastly smaller even than a proton. Among the advantages of string theory is that it appears to neatly represent all known physical forces, including gravity. The original dream of string theory was that theorists could eventually derive a single, unique theory, from which all aspects of our current physical laws, including various constants such as the speed of light and the strength of gravitational attraction, could be deduced. Instead, recent research in the field has led to an enormous ensemble of possible universe designs, which by one reckoning number 10500. Some researchers have reacted to these developments by redoubling their efforts to derive a unique theory. Others have resorted to the anthropic principle, saying that the reason that our universe is so remarkably well-suited for intelligent life is merely an anthropic-principle-based selection effect -- if it were not so finely tuned for intelligent life, we wouldn't be here discussing the topic -- see Anthropic and Multiverse.

    But string theory and the multiverse have their detractors, even among researchers intimately familiar with research in the field. Mathematician Peter Woit writes that "any further progress toward understanding the most fundamental constituents of the universe will require physicists to abandon the now ossified ideology of supersymmetry and superstring theory that has dominated the last two decades" [Woit2006, pg. 264]. In a similar vein, physicist Lee Smolin writes, in sharp criticism of the string theory-multiverse community [Smolin2006, pg. 352]:

    We physicists need to confront the crisis facing us. A scientific theory that makes no predictions and therefore is not subject to experiment can never fail, but such a theory can never succeed either, as long as science stands for knowledge gained from rational argument borne out by evidence. There needs to be an honest evaluation of the wisdom of sticking to a research program that has failed after decades to find grounding in either experimental results or precise mathematical formulation. String theorists need to face the possibility that they will turn out to have been wrong and others right.
  13. Measurements of the Hubble constant

    One other interesting controversy is the measured value of the "Hubble constant" (denoted H0), namely a parameter associated with the rate of expansion of the universe. Since 2015, two different projects, employing two different approaches, have found different values. One project (the Planck project) relies on studies of the cosmic microwave background (CMB), namely the residual radiation from about 380,000 years after the big bang, when the universe cooled to the point that electrons and nuclei could combine to form atoms. The Planck project, which relies on data from the European Space Agency's Planck satellite, measures H0 as 67.4 in the standard units (kilometers per second per megaparsec), with an error margin of 1%, or about 0.6.

    The other project, the Equation of State of Dark Energy (SHoES) project, relies on supernova measurements and the "cosmic distance ladder," namely a tiered system of reckoning of astronomical distances which starts with straightforward parallax measurements of nearby stars in the Milky Way, which are then used to calibrate distances measured by Cepheid pulsating stars in the Milky Way and neighboring galaxies, which are then used to calibrate measurements based on Type IA supernovas (see Distance for additional details). The SHoES project, which has recently refined their techniques, has concluded that H0 is 74.03, plus or minus 1.42. Needless to say, the two measurements are in disagreement by a greater difference than can easily be dismissed by standard experimental error. Adam Riess of Johns Hopkins University, who is a co-leader of the SHoES project, nonetheless sees the disagreement in a positive light [Ananthaswamy2019]:

    At some point, you have to start saying the universe has another wrinkle in it, in the cosmological model -- in the composition of the universe or in some feature of dark matter or dark energy -- [that] could also potentially explain this. ... You have to give that some serious consideration.


In summary, it is most certainly not true that there is any "controversy" regarding the basic outlines of old-earth geology, biological evolution or the history of the universe since the big bang, including the overall time frames (millions and billions of years) involved. These theories have survived decades of fierce scrutiny and debate among professional scientists, and the latest evidence continues to strongly support them. However, secondary and tertiary details of exactly how these processes transpired continue to be investigated, as part of the ongoing process of scientific research in these fields.

In general, there is no evidence whatsoever that there is any sort of "conspiracy" or "group-think" among scientists in the areas of geology, evolution, physics or cosmology. To the contrary, when one peers beneath the smooth public veneer of the world of scientific research, one finds, more often than not, heated debates and disagreements, particularly at the forefront of research where genuine issues remain unresolved. In fact, in a real sense, virtually every scientific paper ever published (and hundreds of thousands are published each year) represents one voice in a debate, either supporting or debunking some other hypothesis or study. Indeed, it is utterly absurd to think that a "conspiracy" or "group-think" could persist more than momentarily in a worldwide community of hundreds of thousands of professional scientists, representing many different nations, cultures and religious traditions, who competitively critique each other's work in scientific journals and conferences, and who evaluate each other's research proposals in highly competitive bids for government funding.

Thus, while the system of scientific publication and peer review is not foolproof, and there have been lapses, nonetheless it works very well in rooting out sloppy reasoning, weak experimental support, as well as any attempts to impose an "orthodoxy" in the field. Scientific progress is real.

For additional discussion, see Conspiracy, Peer review and What is science?.


[See Bibliography].