What is a Scientific Controversy?

The Merriam-Webster Dictionary defines controversy as “a discussion marked especially by the expression of opposing views.” So, what does it mean for something to be a “scientific” controversy?

So, what is a scientific controversy?

As you saw in the exercise above, controversies can take many forms, but many are not considered to be scientific controversies. For instance, ethical concerns are essential when society creates policy, but ethics do not use scientific evidence and so are not scientific controversies (reminder that science cannot answer all questions nor solve all of our problems).

Also, having unexpected results is very common in science, and the fact that things may turn out different than what you expected does not mean that it is a controversy. Even having a single published article contradicting a widely accepted concept does not result in controversy. However, once the scientific community continues to research the concept and is identifying mounting evidence that counters the accepted conclusion, then the concept may be a scientific controversy.

Also seen in the exercise, some ideas may appear to be controversial in science but really are not. This may happen unintentionally. For instance, balanced reporting is generally considered good journalism, and balance does have its virtues. The public should be able to get information on all sides of an issue, but that doesn’t mean that all sides of the issue deserve equal weight. Science works by carefully examining the evidence supporting different hypotheses and building on those that have the most support. Journalism and policies that falsely grant all viewpoints the same scientific legitimacy effectively undo one of the main aims of science: to weigh the evidence.

Theories, Hypotheses, and Laws

To really understand scientific controversies, it is essential to know the relationship between laws, theories, and hypotheses.

Some introductory science courses treat hypotheses as “things we’re not sure about yet” and only explore established and accepted theories. In fact, hypotheses, theories, and laws are rather like apples, oranges, and kumquats: one cannot grow into another, no matter how much fertilizer and water are offered. Hypotheses, theories, and laws are all scientific explanations that differ in breadth, not in the level of support. Hypotheses are explanations that are limited in scope, applying to a fairly narrow range of phenomena. The term law is sometimes used to refer to an idea about how observable phenomena are related—the term is also used in other ways within science. Theories are deep explanations that apply to a broad range of phenomena and that may integrate many hypotheses and laws.

Theories

Theories are broad explanations for a wide range of phenomena. They are concise (i.e., generally don’t have a long list of exceptions and special rules), coherent, systematic, predictive, and broadly applicable. In fact, theories often integrate and generalize many hypotheses. For example, the theory of natural selection broadly applies to all populations with some form of inheritance, variation, and differential reproductive success—whether that population is composed of alpine butterflies, fruit flies on a tropical island, a new form of life discovered on Mars, or even bits in a computer’s memory. This theory helps us understand a wide range of observations (from the rise of antibiotic-resistant bacteria to the physical match between pollinators and their preferred flowers), makes predictions in new situations (e.g., that treating AIDS patients with a cocktail of medications should slow the evolution of the virus), and has proven itself time and time again in thousands of experiments and observational studies.

Hypotheses

Hypotheses are proposed explanations for a fairly narrow set of phenomena. These reasoned explanations are not guesses—of the wild or educated variety. When scientists formulate new hypotheses, they are usually based on prior experience, scientific background knowledge, preliminary observations, and logic. For example, scientists observed that alpine butterflies exhibit characteristics intermediate between two species that live at lower elevations. Based on these observations and their understanding of speciation, the scientists hypothesized that this species of alpine butterfly evolved as the result of hybridization between the two other species living at lower elevations.

Laws

In everyday language, a law is a rule that must be abided or something that can be relied upon to occur in a particular situation. Scientific laws, on the other hand, are less rigid. They may have exceptions, and, like other scientific knowledge, may be modified or rejected based on new evidence and perspectives. In science, the term law usually refers to a generalization about data and is a compact way of describing what we’d expect to happen in a particular situation.

Some laws are non-mechanistic statements about the relationship between observable phenomena. For example, the ideal gas law describes how the pressure, volume, and temperature of a particular amount of gas are related to one another. It does not describe how gases must behave; we know that gases do not precisely conform to the ideal gas law.

Other laws deal with phenomena that are not directly observable. For example, the second law of thermodynamics deals with entropy, which is not directly observable in the same way that volume and pressure are. Still, other laws offer more mechanistic explanations of phenomena. For example, Mendel’s first law offers a model of how genes are distributed to gametes and offspring that help us make predictions about the outcomes of genetic crosses.

The term “law” may be used to describe many different forms of scientific knowledge, and whether or not a particular idea is called a law has much to do with its discipline and the time period in which it was first developed.

Controversies

Fundamental scientific controversy: scientists disagreeing about a central hypothesis or theory. If you imagine scientific knowledge as a web of interconnected ideas, theories and hypotheses are at the center of the web and are connected to many, many other ideas—so, a controversy over one of these principal ideas has the potential to shake up the state of scientific knowledge. For example, physicists are currently in disagreement over the basic validity of string theory, the set of key ideas that have been billed as the next big leap forward in theoretical physics. This is a fundamental scientific controversy.

Secondary scientific controversy: scientists disagreeing about a less central aspect of a scientific idea. For example, evolutionary biologists have different views on the importance of punctuated equilibrium (a pattern of evolutionary change, characterized by rapid evolution interrupted by many years of constancy). This controversy focuses on an important aspect of the mode and rate of evolutionary change, but a change in scientists’ acceptance of punctuated equilibrium would not shake evolutionary biology to its core. Scientists on both sides of the punctuated equilibrium issue accept the same basic tenets of evolutionary theory.

For an overview of the relationship between theories and laws, watch the following video:

Honesty is the Best Policy

In science, honesty really is the best policy—even if that means publicizing a slip-up. Geoffrey Chang, a professor at the Scripps Research Institute, has made a successful career working out the physical structures of proteins used in cell membranes. His work was published in top journals and cited by other scientists many times. Then, in 2006, he found a mistake. Prompted by conflicting results from other researchers, Chang discovered that, for the past five years, he had been analyzing his data with a flawed computer program, leading to incorrect results. So what did he do? Exactly what the culture of science expected of him: he published letters retracting his previous work, offered an apology, and then started the work of reanalyzing his data in order to correct his results.

What happens when someone within the community doesn’t meet those expectations? In science, not playing by the rules amounts to scientific misconduct, or at least scientific misbehavior. Serious misconduct is rare, but nevertheless, because scientists are people and have human frailties, it does happen. Perhaps a chemist is asked to review the paper of a personal friend and chooses to overlook a flaw in the research; thus, failing to fairly scrutinize the work. Perhaps a physicist performs an experiment and chooses only to report results that fit with his or her favorite hypothesis; thus, failing to be fully honest. Perhaps a biologist writes a research article but doesn’t cite a previous study that inspired the work; thus, failing to assign credit fairly. Or perhaps a psychologist studies a group of students’ problem-solving skills but circumvents a few guidelines about how the participants should be recruited; thus, failing to work within the ethical guidelines established by the scientific community. Such behavior works against one of science’s main goals: to build accurate knowledge about how the world works in ways that are ethical and humane.

Now that you have learned about scientific controversies, let’s look at an example that is commonly referred to as a controversy, but it actually is not. We will look at the history of how the connection of vaccination and autism was created and how this led to further investigation and eventually, an article being retracted—an extremely rare event.

Because it undermines science, scientists take misconduct very seriously. In response to misconduct, the scientific community may withhold esteem, job offers, and funding; effectively preventing the offender from participating in science. For example, a scientist found to have plagiarized parts of a grant application to the National Institutes of Health will likely be prevented from participating in federally funded grants for a period of time—a tough punishment for someone whose salary may be partly dependent on such grants. Some types of misconduct are even punishable by law. For example, because he faked data in funding applications and journal articles, medical researcher Eric Poehlman received a $180,000 fine, a year in prison, and a lifetime ban on receiving federal research funds!

Serious and damaging cases of scientific misconduct are almost invariably found out. That’s because science is designed to get at how the world really works. Any fraudulent results that paint a false picture of the world will be uncovered as science proceeds and zooms in on the true picture. For example, in the early 1900s, the influential physiologist Emil Abderhalden claimed to have shown that humans produced protective enzymes that could be used in many practical ways—foremost among them, detecting pregnancy. The only problem? Such enzymes don’t actually exist. So, of course, Abderhalden’s fraud was eventually found out by other scientists who could not reproduce his test results and found that his pregnancy test simply didn’t work.

Science’s system of scrutiny, peer review, and checks and balances help accelerate the process of discovering and weeding out occasional cases of fraud. For example, the world was first clued into Woo Suk Hwang’s fraudulent claims regarding stem cells when other scientists scrutinizing his work drew attention to an anomaly: some of his data looked too good to be true. DNA fingerprint graphs purportedly representing DNA from different samples showed peaks that seemed to be exact duplicates of one another—more likely the result of image manipulation than actual DNA fingerprinting analysis. The ensuing investigation revealed that the copycat graph peaks were only the tip of the iceberg. In fact, Hwang’s basic claim—that his lab had cloned human embryos and collected stem cells from them—turned out to be entirely fabricated!

Such flagrant examples of fraud can be disturbing and should lead to the indictment of offenders, but they should not lead to the indictment of science. Science has many safeguards in place to prevent fraud, and when fraud does happen, science has mechanisms for detecting it. Scientific misconduct may temporarily lead science towards incorrect conclusions, but the ongoing processes of science regularly correct such diversions.

Examples

Let’s look at some examples of science topics to determine if and to what extent they are scientific controversies.

Vaccines & Autism

Does vaccination cause autism, and is this a scientific controversy?

As emphasized by the World Health Organization and the Centers for Disease Control and Prevention, there is no evidence supporting that vaccination causes autism.

The idea of this possible link began by Wakefield and his research group when they published a paper in “The Lancet” journal in 1998 titled “Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children” (see the original article, which has since been retracted). In the article, Wakefield et al. (1998) claimed that “In eight children, the onset of behavioural problems had been linked, either by the parents or by the child’s physician, with measles, mumps, and rubella vaccination.”

After years of investigation and additional research studies—all of which found no link between autism and vaccination (Eggertson, 2010)—the General Medical Council held a hearing in 2010. During this hearing, Wakefield “admitted and found proved” that the research was funded by Mr. Barr, who “had the benefit of public funding from the Legal Aid Board in relation to the pursuit of litigation against manufacturers of the MMR vaccine” (p. 4).

Additionally, the children in the study were not randomly selected for the study. Rather, according to the General Medical Council (2018), each child in the study was carefully selected after conversations with the children’s parents and doctors. For instance, the report described procedures for the selection of each child, and Child 3 was referred by the child’s general practitioner for having “behavioural problems of an autistic nature, severe constipation and learning difficulties all associated by his parents with his MMR vaccination” (p. 18). “In reaching its decision, the Panel concluded that [Wakefield’s] description of the referral process as “routine”, when it was not, was irresponsible and misleading and contrary to [Wakefield’s] duty as a senior author” (p. 46).

The General Medical Council (2018) also found other irresponsible measures such as telling assistants to increase the amount of medication without reporting it to the doctor and taking blood samples from children at his son’s birthday party (documented on pages 50-56).

Wakefield and the so-called link between vaccination and autism are both discredited, and Wakefield is no longer a practicing physician. In 2016, Wakefield directed a propaganda movie called “Vaxxed: From Cover-Up to Catastrophe.” The movie was supposed to air at the Tribeca Film Festival but was pulled (Ryzik, 2016). Robert De Niro, one of the founders of the festival, originally supported the movie but later denounced it (Ryzik, 2016). Although, as of August 2020, a video clip of him supporting it is still on the Vaxxed website.

So, is this a scientific controversy? The Wakefield article caused scientists to investigate the potential for a relationship. But, no additional evidence was found showing a link between vaccination and autism, making the only “evidence collected” based on a retracted article written by a discredited physician. Therefore, the idea of any link between vaccines and autism is not a scientific controversy.

CRISPR

Genome editing technologies enable scientists to make changes to DNA, leading to changes in physical traits like eye color and disease risk. Scientists use different technologies to do this. These technologies act like scissors, cutting the DNA at a specific spot. Then scientists can remove, add, or replace the DNA where it was cut.

The first genome editing technologies were developed in the late 1900s. More recently, a new genome-editing tool called CRISPR, invented in 2009, has made it easier than ever to edit DNA. CRISPR is simpler, faster, cheaper, and more accurate than older genome editing methods. Many scientists who perform genome editing now use CRISPR.

One way that scientists use genome editing is to investigate different diseases that affect humans. They edit the genomes of animals, like mice and zebrafish, because animals have many of the same genes as humans. For example, mice and humans share about 85 percent of their genes! By changing a single gene or multiple genes in a mouse, scientists can observe how these changes affect the mouse’s health and predict how similar changes in human genomes might affect human health.

Scientists also are developing gene therapies—treatments involving genome editing—to prevent and treat diseases in humans. Genome editing tools have the potential to help treat diseases with a genomic basis, like cystic fibrosis and diabetes. There are two different categories of gene therapies: germline therapy and somatic therapy. Germline therapies change DNA in reproductive cells (like sperm and eggs). Changes to the DNA of reproductive cells are passed down from generation to generation. Somatic therapies, on the other hand, target non-reproductive cells, and changes made in these cells affect only the person who receives the gene therapy.

Even though CRISPR improved upon older genome editing technologies, it is not perfect. For example, sometimes genome editing tools cut in the wrong spot. Scientists are not yet sure how these errors might affect patients. Assessing the safety of gene therapies and improving genome editing technologies are critical steps to ensure that this technology is ready for use in patients.

There are also several ethical concerns that can emerge with genome editing, including safety. First and foremost, genome editing must be safe before it is used to treat patients. Some other ethical questions that scientists and society must consider are:

• Is it okay to use gene therapy on an embryo when it is impossible to get permission from the embryo for treatment? Is getting permission from the parents enough?
• What if gene therapies are too expensive and only wealthy people can access and afford them? That could worsen existing health inequalities between the rich and poor.
• Will some people use genome editing for traits not important for health, such as athletic ability or height? Is that okay?
• Should scientists ever be able to edit germline cells? Edits in the germline would be passed down through generations.

Most people agree that scientists should not edit the genomes of germline cells at this time because the scientific communities across the world are approaching germline therapy research with caution since edits to a germline cell would be passed down through generations. Many countries and organizations have strict regulations to prevent germline editing for this reason. The NIH, for example, does not fund research to edit human embryos.

There are many applications of CRISPR, including medical treatments (similar to gene therapy), agriculture (genetically modified organisms), and conservation (adding genetic diversity to species or de-extincting species—described in the next section). Many of these applications have non-CRISPR alternatives that have been around longer. For instance, scientists are researching how CRISPR can be used to treat cancers rather than chemotherapy. Given the novelty of CRISPR, its effectiveness and safety are continually studied and compared to traditional approaches. Depending on the findings of the research, some of these applications may be a scientific controversy and will take time to solve.

De-extinction

One of the more interesting conservation debates to have emerged in recent years involve efforts to reverse extinction. This field, known as de-extinction or resurrection biology aims to revive extinct species, and eventually to reintroduce viable populations to their original locations (Seddon, 2017).

One possible method, called “breeding back”, aims to produce individuals genetically similar to an extinct species by selective breeding of extant species that carry the genetic material of their extinct relatives. This is the main method currently being used to revive the aurochs (Bos primigenius), the ancestor of today’s domestic cattle (Stokstad, 2015). Other “breeding back” projects place less emphasis on genetics and more on morphology, by selectively breeding individuals with certain traits to produce individuals that visually appear similar to the extinct species. Such is the case at The Quagga Project, where selectively breeding of plains zebras (Equus quagga) with quagga-like characteristics (reduced striping and brown hues) are resulting in animals that look increasingly like extinct quaggas (Harley et al., 2009).

The second popular method used for de-extinction is cloning. This involves the transfer of viable genetic material from an extinct species to the eggs (or embryo) of a closely related surrogate mother, who will hopefully give birth to an individual of the extinct species. Cloning has been used in selective breeding of livestock for many years, and plans are also currently underway to use cloning to prevent the extinction of highly threatened species such as the northern white rhinoceros.

Despite the promise that cloning offers for reviving extant and recently extinct species, cloning species that went extinct many years ago has been more challenging. So far, attempts to clone Spain’s Pyrenean ibex (Capra pyrenaica pyrenaica) and Australia’s gastric-brooding frog (Rheobatrachus silus) have produced individuals that lived for only a few minutes (Ogden, 2014).

Despite the progress made, de-extinction is one of the most controversial and polarising debates to emerge among conservation biologists in recent years. Proponents of de-extinction hope that the early work described above paves the way for the resurrection of extinct species once the threats that drove them to extinction have been managed. Many de-extinction biologists have even started establishing banks where the genetic material of threatened species is cryopreserved for future use.

References

Controversy. (n.d.). Merriam-Webster Online Dictionary. Retrieved from https://www.merriam-webster.com/dictionary/controversy

Eggertson L. (2010). Lancet retracts 12-year-old article linking autism to MMR vaccines. CMAJ: Canadian Medical Association journal = journal de l’Association medicale canadienne, 182(4), E199–E200. https://doi.org/10.1503/cmaj.109-3179

General Medical Council. (28 January 2010). Fitness to practice panel hearing. Retrieved from The NHS website for England https://www.nhs.uk/news/2010/01January/Documents/FACTS%20WWSM%20280110%20final%20complete%20corrected.pdf

Harley, E.H., M.H. Knight, C. Lardner, et al. 2009. The Quagga project: Progress over 20 years of selective breeding. South African Journal of Wildlife Research 39: 155–63. https://doi.org/10.3957/056.039.0206

Ogden, L.E. 2014. Extinction is forever… or is it? BioScience 64: 469–75. https://doi.org/10.1093/biosci/biu063

Ryzik, M. (1 April 2016). Anti-vaccine film, pulled from Tribeca Film Festival, draws crowd at showing. The New York Times. https://www.nytimes.com/2016/04/02/nyregion/anti-vaccine-film-pulled-from-tribeca-film-festival-draws-crowd-at-showing.html

Seddon, P.J. 2017. The ecology of de-extinction. Functional Ecology 31: 992–95. https://doi.org/10.1111/1365-2435.12856

Stokstad, E. 2015. Bringing back the aurochs. Science 350: 1144–47. https://doi.org/10.1126/science.350.6265.1144

Wakefield A, Murch S, Anthony A; et al. (1998). Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. The Lancet. 351(9103): 637–41. doi:10.1016/S0140-6736(97)11096-0. PMID 9500320.

Attributions

This chapter is a modified derivative of the following articles:

“Extinction is Forever” by Wilson, J. W., & Primack, R. B., Conservation Biology in Sub-Saharan Africa, 2019, Cambridge, UK, Open Book Publishers, CC BY 3.0.

Understanding Science. 2020. University of California Museum of Paleontology. 11 June 2020 <http://www.understandingscience.org>.

“What is Genome Editing?” by National Human Genome Research Institute, National Institutes of Health, 2019, Policy Issues in Genomics, Public Domain.