15 Scientific Consensus


Scientific consensus is really a misnomer. The term consensus, as defined by Merriam Webster, is “a general agreement: an idea that is shared by all the people in a group.” However, scientific consensus does not include the ideas and opinions of every scientist. Rather, scientific consensus is defined loosely as a position held by most scientists at the time on a certain issue. To reiterate, scientists do not have to be unanimous for scientific consensus to be reached. However, as mentioned previously, consensus is an idea shared by all members of a group. At Haverford, students are taught that if just one person disagrees with a general opinion, consensus cannot be reached. This disparity then between true consensus and scientific consensus becomes problematic when scientific consensus becomes a validation. What this chapter will focus on is how scientific consensus has come to shape many parts of society because it is often labeled as fact and absolute truth. Throughout history, scientific consensus has held many theories to be true that have later proven to be incredibly false. As this chapter will further elucidate, for years scientific consensus has held that theories such as the earth is flat and that earth is the center of the universe. These theories, along with many others, have been shown to be categorically false. However, other theories exist presently that a large portion of human society accepts because they are substantiated by scientific consensus. However, just because scientists generally agree on an issue, people blindly follow consensus without evaluating the research or understanding the issue for themselves . This can lead to misunderstandings of issues or inaccurate beliefs in something. Likewise, not evaluating why scientists believe something can lead to quick assumptions contrary to overwhelming scientific evidence. In turn, policy and society can be shaped by these misconceptions in substantially sweeping ways. This chapter will look specifically into misconceptions regarding global warming, vaccines and the creation of the universe.

Global Warming

At least in America, there seems to be a considerable amount of awareness around global warming. Most people have at least heard of global warming, and many of them know generally what the theory suggests. Briefly, scientific consensus holds that humans have increased the amount of certain gasses in our atmosphere. These aforementioned gasses are commonly referred to as greenhouse gasses. While there are a few gasses responsible for the phenomena of global warming, the gas that is considered to be the largest contributor to global warming is carbon dioxide (CO2). (National Geographic) Other impactful greenhouse gasses include methane and water vapor. These gasses are proficient at trapping heat – a necessary occurrence within our atmosphere. Greenhouse gasses are paramount to maintaining life since without them, a lot of the sun’s heat would escape our atmosphere; heat that is needed for life. However, while these gasses are necessary to some degree, the recent proliferation of these gasses has caused a warming effect felt by the entire planet. This effect is called global warming. At least, this is what scientific consensus tells us. No matter how old you are, if you had never once heard of global warming, you would be extremely skeptical of this theory. Most people who don’t have access to vast databases and advanced research equipment probably would not have noticed any warming. The seasons have come and gone unfailingly for however many years you have lived. However, the reason you most likely haven’t noticed a change in global temperature is because the aggregate change is so relatively small that it is unnoticeable. According to scientists at NASA, since 1880 the earth has increased in temperature by about 8 degrees Celsius or 1.4 degrees Fahrenheit with most of the warming occurring within the last few decades. (NASA.gov) This data is also significant since this increase in Earth’s mean temperature goes largely uncontested.

While Earth’s temperature escalation is shown to be almost indisputable, the public understanding of it is often skewed or inaccurate. Generally the public knows that global warming exists. A Gallup poll indicates that roughly 97% of Americans either have some or a great deal of knowledge about global warming. (Gallup.com) However, an article published by Richard Bord et al. (year) demonstrates that what the public understands about global warming is often inaccurate since their comprehension is based off of a jumble of experimental data and mental models. One such mental model referenced in the article is the “pollution model”. The “pollution model” encapsulates the mentality held by members of the public that pollutants generally are the cause of global warming. Rather than realizing that greenhouse gasses have been shown by scientists to be the primary cause of global warming, people attribute the phenomena to their own misconceptions. As identified in the article, “[the pollution model] leads to significant errors in judgment that could affect policy in important ways. For example, many people think that the installation of scrubbers in industry smokestacks reduces greenhouse gases; the opposite is true.” (Bord, 78) This highlights a large problem with scientific consensus. While pollution is universally harmful to quality of life and well-being, pollution, as a collective is not the cause of global warming, at least not according to scientific consensus on global warming. Science is confusing to many people for any number of reasons. Either from counterfactual sources or from lack of education on the topic, scientific consensus means that people can blindly accept something to be true without evaluating why it is true. In the aforementioned article, Bord and his co-contributors cite a study that shows people attributing global warming falsely to nuclear power. While nuclear power and subsequently nuclear waste has far flung negative effects on the environment, nuclear power in and of itself is not a cause of global warming insofar as scientific consensus on it has shown.

Despite scientific evidence that shows causation between human activity and global warming, there are those that disagree with it. That’s not to say these skeptics have a particularly loud voice. A Gallup poll indicates that 58% of the population believes that global warming is caused by natural causes. (Gallup.com) Scientists are even less divided with a Pew Research survey finding that 87% of AAAS scientists agree that human activity is to blame for global warming. (Pew Research Center) So what is the contentious view of those not in agreement? These skeptics believe that the world is warming due to natural causes. Many believe that the Earth goes through these cycles of period warming as CO2 is released into the atmosphere. The warming observed today is just another of those periods, with a similar period of global warming occurring 56 million years ago. Then as it is now, the Earth was able to remove the extra CO2 from the atmosphere and bring the global mean temperature back down. (wunderground.com) So who are the people that are most skeptical about global warming? Reley Dunlap and Aaron McCright contend that Republicans are the most prominent skeptics as a collective of the scientific consensus theory of global warming, “a significant part of the U.S. conservative movement—made up of conservative foundations, think tanks, media, and public intellectuals—mobilized in the 1990s to challenge both climate science and climate policy.” (Dunlap, 27) The takeaway from this polarization on this theory between the two main political parties isn’t so much that it exists, but why it exists. While some people simply attribute this dispersion to party politics, the reason behind Republican skepticism of global warming reveals the societal and political effects of scientific consensus. Republicanism has a strong aversion to “big” government regulation, and rather un-coincidentally, the way to avoid further global warming, as scientists believe it is being caused, is for the government to regulate with policy. The most effective way to mitigate human effects on climate change is to reduce carbon emissions. However, stopping private sector business from emitting large amounts of carbon dioxide is hard and requires effective public policy. Limits on factory emissions and car emissions could effectively reduce human’s impact on the climate. Therefore, what Dunlap and McCright demonstrate in their article is how scientific consensus on this issue of climate change could bring about policies, and has in certain European countries, which will change society and private sector business practices.


Vaccines are fairly commonplace now within society. Most children have had a vaccine at least once in their life, and more and more people seem to be of the belief that all children should receive mandatory vaccines. This is substantiated in a survey conducted by the Pew Research Center. The survey demonstrates that 68% of people believe that children should receive mandatory vaccination. (Pew Research Center) Rather unsurprisingly, scientific consensus is in agreement with the public. The same survey shows that 86% of AAAS (American Association for the Advancement of Science) scientists believe that children should receive mandatory vaccination. (Pew Research Center) Indeed, there appears to be generally a lot of trust in vaccines in our society, and they seem to have more benefits than costs. Major news networks like CNN have articles that begin with absolute statements such as, “Children should get vaccinated against preventable and potentially deadly diseases. Period.” (CNN.com) Forums and blogs display similar sentiments, demonstrating a lot of people’s absolute belief in the safety of vaccines and the benefits that vaccines have. On one such forum, countless parents praised vaccines for being unconditionally safe while citing no empirical evidence to support their assertions. The faith in the scientific consensus regarding the safety of vaccines, while possibly well placed, may be too ardent and should be tempered. As this section will demonstrate, there are very few negative side effects from vaccines. In fact, extreme side effects are incredibly rare. The CDC (Center for Disease Control and Prevention) claims severe problems with most vaccines only occur in no less than 1 in every 100,000 cases, and with many other vaccines no less than 1 in ever million cases. (CDC.gov) So while these statistics may demonstrate the low risk in receiving a vaccine, placing absolute belief in scientific consensus is dangerous.

Vaccines according to the CDC, “are the best defense we have against infectious diseases; however, no vaccine is actually 100% safe or effective.” (CDC.gov) Indeed, there have been a few cases in history where vaccines have caused more harm than good, or at least had the potential to do so. One such incident of this is the Cutter Incident in 1955. This incident involved a number of batches of polio vaccine containing live polio virus. Over 250 cases of polio were attributed to these batches of the vaccines. (Fitzpatrick, 156) In another instance, there was a slightly higher risk of a neurological disorder called Guillain-Barré Syndrome when given a swine flu vaccine in 1976. The increased rate of acquiring this syndrome was low with 1 additional case in every 100,000 people who received the vaccine. However, the Institute of Medicine noticed this heightened risk in a scientific review of the vaccine and immunization was stopped until the issue could be further explored. (CDC.gov) One final instance of a vaccination problem is in 2009-2010. In this case, certain European countries noticed an association between narcolepsy and Pademrix, a H1N1 influenza vaccine. Pandemrix, produced by GlaxoSmithKline, was never licensed in America. Furthermore, a study released by the CDC later found that there might not have been any association between narcolepsy and the vaccine. (sciencemag.org) These three cases outlined above don’t demonstrate an egregious issue with vaccination. Rather, each of these issues shows that there are problems associated with vaccines that shouldn’t be ignored – or at least should be evaluated and considered.

People can also misunderstand scientific consensus in another way. People put faith in something that has shown to be harmful, as noted above. However, people can also very quickly assume something because they don’t fully understand what scientific consensus really means. To elucidate, there was significant media attention in the early 2000s regarding a supposed link between autism and the MMR (measles, mumps and rubella) vaccine. This association between the vaccine and autism was anecdotal or based on invalid research data. Andrew Wakefield published this fraudulent data in a case study. In this case study, Wakefield looks at 12 patients and observes a causal link between the MMR vaccine and autism. However, a number of years down the line this case study was officially debunked, and scientists are in consensus that there isn’t a causal link between the vaccine and autism. (independent.co.uk) As Uri Shwed and Peter S. Bearman “Regarding the idea that MMR vaccinations cause autism, our analysis reveals that this issue has never carried any scientific contestation.” (Shwed, 883) As Shwed and Bearman discuss in their article, most scientists have remained in agreement on the issue of autism and vaccination. There is no scientific evidence to support the claim that autism would be related to vaccine, only correlation. Despite the lack of any empirical evidence, the media and the public still took significant stock in the correlation. An article written by Christopher Clark notes that the media’s attention on the Wakefield report reduced uptake of the vaccine by 30%. (Clarke) Along with this radical change to social policy, there was also more general apprehension regarding vaccines. As Clarke references, people were unsure which vaccines to trust. Clarke throughout his article discusses this cultivation of doubt and how the media was able to take skeptical science vis-à-vis the Wakefield report, and turn it into a seemingly credible piece of research. As Clarke mentions, “In doing so, the media was in effect ‘creating science’ in lieu of a scientific consensus emerging. Furthermore, health officials have argued that because the media balanced the claims of supporters of an autism-vaccine link with those of skeptics (i.e., the majority of the scientific community), they created a discourse that emphasized uncertainty.” (Clarke, 86) People don’t really understand scientific consensus. As soon as a sensational study is released, people willingly accept that study to be true despite overwhelming evidence on the contrary. That’s not to say people should just blindly accept that vaccines are foolproof, since that would also be negligent. Rather, people need to make educated decision and look into the science behind a scientific finding. If people understood what scientific consensus is, they wouldn’t believe a sensational story about autism and vaccines. However, as this chapter has been trying to show, blind faith is not a solution either.

The Universe

While the other sections in this chapter have focused on how there is more to an issue than just the general consensus of scientists, this section will demonstrate how scientific consensus can evolve over time. That is to say, while consensus may say one thing at one moment in time, it can change radically as science becomes more advanced and technology becomes more sophisticated. To encapsulate the aforementioned trend, this section will look at scientific consensus about Earth, our solar system and the universe. One such debate that demonstrates the change in scientific consensus is the geocentric and heliocentric debate. A geocentric view of the universe is that the Earth is the center with every other planet and star orbiting the Earth. A heliocentric view holds that the Sun is the center of our solar system and that the Earth orbits around it. Initially, scientific consensus held for years the geocentric view of the universe. Not until Nicolaus Copernicus around the year 1532 did this theory change. Copernicus discovered that, due to the retrograde motion of planets, the Sun must be the center of the solar system. Theories about the solar system have changed since his time and have grown more detailed and accurate. However, what Copernicus demonstrates about scientific consensus is that it can shift radically as scientists observe new traits about the universe. If he, or any other scientist were to simply accept the contemporary belief at the time and not challenge a consensus, then new scientific discoveries would never be made. Furthermore, it shows just how easily the public can accept scientific consensus as fact. Just because science has shown something to be true now doesn’t mean it has to be true forever. There are complications in scientific consensus and people have to realize this by doing their own analysis. Acceptance of anything without understanding the science behind it is dangerous, and can lead to false conclusions.

Furthermore, another example of how scientific consensus can change is the theory of the big bang. This theory, like the theory about the solar system and Earth’s place within the universe, has had an evolving history as well. For instance, just within the last century, Albert Einstein proposed his version of the static universe in 1917. A number of years later in 1929, Edwin Hubble announced his finding that the entire universe was expanding. Hubble noticed distinctive redshift in far away galaxies leading physicists to the eventual theory of the big bang. George Gamow popularized the theory, which holds that the entire universe expanding from a very massive, and high temperature state, in the 1940s (Bynum). However, despite this being the countervailing theory and the one most scientists agree upon, there are many contradicting theories about the creation of the Universe. An article written by Graeme Rhook and Mark Zangari demonstrates their issue with the scientific consensus on the theory stating, “we suggest that the big bang program, rather than being a highly corroborated and satisfactory account of the large scale universe, has a probability of ultimate success that does not justify I its current dominance of contemporary cosmology” (Rhook, 228) Rhook and Zangari believe that the big bang doesn’t account for many anomalies with research findings. In particular, they cite discrepancies in findings of redshift, saying that the predominant theory hasn’t accounted for all the observations that have been made. Rhook and Zangari find other complications with this theory, but what is more important to this section is how their opinion contrasts with someone who buys the big bang model. William Bynum puts forward a defense for the theory in his book A Little History of Science arguing that, “There is still a lot of disagreement about details, and even about some of the fundamental principles, but that is not unusual in science. The Big Bang model can make sense of much that can now be measured, including the red shifts of distant starts, background cosmic radiation and the fundamental atomic forces.” (Bynum, 250) While this chapter won’t debate the pros and cons of each individual notion about the creation of the universe, what is important to nice is that there is divergence in this area. Both Rhook et al. and Bynum have their own theories on the creation of the universe, and they’re not the only ones that share their respective opinions. As Bynum even notes in the above quotation, there is disagreement in science, and that isn’t unusual. Therefore, while both theories have their merits, it’s dangerous to accept any one theory just because most scientists share that opinion. Scientific consensus changes, and theories about the creation of the universe are constantly changing. This is why one should further explore the science behind scientific consensus, and understand the counterarguments for a given position.


Scientific consensus is often all the public knows about a certain issue. For instance, the public generally knows that GMOs (Genetically Modified Organisms) are safe and that cellphones don’t give you cancer. Along those same lines, a lot of people are aware of carcinogens. People realize that smoking and having an x-ray taken raise your chances of getting cancer. However, the problem isn’t that people know the scientific consensus on an issue; the problem arises when people accept scientific consensus as being absolute and gospel. Accepting scientific consensus can have drastic changes on public policy and society as a whole. The acceptance that human activity is the cause of global warming has had societal impacts, and could lead to drastic political impacts too. However, while it might be beneficial for the Earth to have new policies in place to limit carbon emissions, or mandatory vaccinations to guarantee universal health, not all scientific consensuses has stood the test of time. Theories about the universe have changed significantly, even just within the last few decades. Therefore, while scientific consensus may seem like fact in the moment, evidence could prove it to be categorically false in the future. Therefore, people should educate themselves in science and understand why a belief in something exists. Individual evaluation in the science behind scientific consensus will help make this world a better place. People can’t be moved to hysteria when a bogus study is released, since they understand why they believe in something. Hopefully in time, people will realize that scientific consensus is not infallible and people will educate themselves on topics they don’t understand.


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