Science mistakes – debunking a trope loved by pseudoscience

I know I shouldn’t use the conspiracy theory fallacy when talking about the pseudoscience-pushing science deniers, who provide bread and butter of topics for skeptics. I keep observing the same ridiculous and insanely illogical arguments used in the same manner by all of the deniers, including the oft-repeated “science mistakes” trope. Honestly, I think the pseudoscience pusher meet annually in Sedona, Arizona, ground zero of woo, to discuss which trope they’re pushing this year.

The anti-vaccine zealots, creationists, anthropogenic global warming deniers, and whomever else pretends to use science to actually deny science frequently focus on this theme of “science mistakes.”  And then they produce a list of cherry-picked examples that “prove” that science is wrong (see Note 1). Of course, this indicates more of a misunderstanding of what is science and the history of science than it is a condemnation of science. But your typical science denier is probably not going to let facts get in the way of maintaining faith in their beliefs. So let’s deconstruct and discredit this “science mistakes” trope.

By the way, in my story, I admit that there are many “science mistakes,” so read on. Hopefully, it’s somewhat enlightening.

What is science?

This is where the science deniers get it all wrong. They think that science is some ivory-tower based wizard who stands at the top of a mountain and proclaims loudly, “I have had a vision, and it tells me that vaccines are safe and effective. So sayeth SCIENCE!”

Seriously, get into a discussion with any science denier and eventually, it’s clear they don’t know how science works, after which they will list out all the science mistakes that ever happened. You just want to hit your head against the wall in frustration.

In the real world, science is actually a logical method to answer questions about the natural universe. It is a way to describe and to understand everything around us, whether it is our own health or the stars that shine in the night sky. Science is a process that attempts to remove bias and provide an answer to the question that can stand up to criticism. It is not magical, and it certainly is not incomprehensible. Science is not based rhetoric and debate but on experimentation and open publication.

Even though the vaccine deniers have proclaimed that “vaccines cause autism”, it is not scientific. Let’s go through real science, using the scientific method to examine potential links between vaccines and autism

That hypothesis needs to be tested in unbiased studies, and the results must be available for public review, and, if necessary, critique. And it takes money, time, hard work, and lots of intellectual prowess to design and analyze the results. And lots of people have actually tested the hypothesis that vaccines cause autism, and they have refuted the hypothesis, clearly showing that vaccines do not cause autism.

But more than that, science rarely uses the term “proven”, because the scientific method is not a system to make a definitive answer to any question – scientific knowledge is always provisional. Scientists always leave open the possibility of an alternative hypothesis that can be tested. If the alternate hypothesis can be supported through experimentation, then it can replace the original one. If you have a conversation with anyone who adores pseudoscience, including our favorite anti-vaccine squad, they embrace their conclusions, irrespective of evidence. That is not science.

Yes, there are science mistakes, all the time. In fact, one of the goals of the scientific process is precisely what defines scientific skepticism, a term frequently co-opted by science deniers, which is a process of evaluating a claim based on the quality and quantity of evidence supporting that claim. A real scientist (or scientific skeptic) is looking for errors because it is a part of the process.

However, there are some parts of science that are as close to factual as you can get. The scientific theory of evolution is a fact. The mountains of evidence that support evolution by natural selection and genetic drift are unassailable. That being said, there is a tiny chance (and by tiny, I mean microscopic) that science got it all wrong. There is a Nobel Prize waiting for someone who can provide an alternative explanation for the common descent of all species over time from the moment the first cell arose in the primordial soup 3.5 billion years ago.

But to earn that Nobel Prize, you can’t just say that the theory is wrong, you must show it using the scientific method. And trust me, more real scientists look at the mechanisms for evolution (since evolution is a fact, they’re not denying evolution) for new ideas, since it can provide those scientists with fame and fortune.

Because science is not based on dogma or faith, it is self-challenging and self-critical, uncovering errors is part of the process that makes good science. And science is unbiased. The proper method of science is not to invent a conclusion, then find evidence that supports it. It actually works by gathering all of the evidence, deciding which is high quality and which is junk, then determining where that evidence leads. If I were a paleontologist, and I found a fossilized cell phone in Precambrian rock (about 500 million years old), I’d be wondering about a lot of things. But it wouldn’t eliminate evolution as a fact, I might hypothesize that someone had figured out time travel (which is a problem for physicists, let them deal with it).

So, let’s review. Science isn’t a proclamation from a mysterious group of wizards. Science isn’t definitive, though, in a lot of areas of knowledge, it is about 99.999999999999% definitive (which does not round down to 0%, as a lot of science deniers will do).

Science is not dogmatic. Science does not accept false dichotomies, that it’s either black or white. And as opposed to science deniers, who think that they have the one truth, real science makes mistakes and uncovers it rather rapidly.


Science is obviously wrong about everything. Including unicorns. Obviously wrong about unicorns.

What’s the scientific method?

I mentioned the scientific method in the previous section, so I guess I need to spend a moment to describe it. Once again, it is not magical, but it is a difficult process, despite what the pseudoscience pushers describe.


  1. Define the question – this could be anything from “does this compound have an effect on this disease?” or “how does this disease progress?”  Or if we want to keep this in the world of vaccines, “what causes autism?”
  2. Observations – this is the subjective part of science. Do we observe trends or anomalies? Does a physician notice that every patient from a town or neighborhood exhibit the same disease? A lot of science arises from observations of the natural world, and yes, some of those observations can be anecdotes or personal observations. For example, one of the most famous stories in the early history of medicine is when Edward Jenner observed that milkmaids rarely were infected with smallpox because they were exposed to cowpox, a less virulent disease. Even though anecdotes can be a part of the scientific method, they are not data, and they are rarely used to develop an answer to a question, especially in medicine.
  3. Hypothesis – using the observations, create a hypothesis that can be tested. We can establish a hypothesis that “vaccines are causally linked to autism spectrum disorders.”
  4. Prediction – this is an important step where the researcher tries to predict the results, not to bias it, but to determine the best way to design the experiment. Most importantly, the prediction cannot be correct simply by coincidence – it must be supported by statistical significance. Furthermore, proper scientific method is less biased if the answer to the prediction is not already known.
  5. Experiment – fundamentally, the scientist then tests the hypothesis with experiments and collects the data. The experiments are not designed to solely validate the hypothesis but may also attempt to refute (or nullify) it. In real science, attempting to nullify one’s own hypothesis is an honorable pursuit. Furthermore, the experiments are designed to remove as many biases as possible. For example, the randomized controlled study is considered the gold standard of medical study, because it removes almost all bias from both the subject of the study (the patient) and the physician (See Note 2).
  6. Analyze – examining the results carefully, usually using acceptable statistical methods. Many pseudoscientists will try to obfuscate results with non-standards or even useless statistical measurements. That’s why reading a study’s abstract isn’t really useful, if you don’t spend time analyzing the analysis.
  8. Publish – in today’s scientific community, scientific data and analysis is subject to the scrutiny of other scientists before it can be published, a process called “peer-review.” This is a critical step that ensures that the results can stand up to criticism of others, a key part of the scientific method – putting the results under the bright lights of further analysis and critique.


Settled science, like the theory of evolution, the safety and effectiveness of vaccines, the safety of GMOs, and man-made climate change require a high quantity of high-quality scientific evidence. It is arrogance to believe that you can personally overrule that science without a similar quality and quantity of evidence.

But nowhere do I write that scientific conclusions are perfect. It is a self-correcting system, and for science to come to a consensus takes years and decades of accumulated high-quality evidence. That’s what the pseudoscience side fails to grasp – science is not an opinion. It is not rhetoric. It’s not a debating point. Either there is evidence to support a conclusion or there is not – it deals in facts.

The case of the Piltdown Man

Science deniers are still using that old story to “prove” that science makes mistakes. Let’s set aside the fact that the overwhelming majority of scientific evidence supporting evolution has not been shown to be fraudulent, the creationists use it as their evidence that all evolution is a lie.

Except for one small thing. The story isn’t quite what the evolution deniers claim it is. For those of you who don’t know, Piltdown Man was a hoax perpetrated by an English amateur archeologist, who had combined a modern human skull with a jaw of an orangutan. It was announced in 1912 and was used as “proof” (there’s that nonscientific word) that man descended from apes.

Right from the beginning, a lot of experts (by that, I mean professional scientists who studied archeology and human evolution) disputed everything about the so-called fossil, but back then, we didn’t have the scientific techniques, like radiocarbon dating, that might have quickly debunked the hoax. By 1954, using modern scientific techniques, it was shown to be a deception. In other words, a non-scientist perpetrated a scam. And real science uncovered it. Moreover, if someone tried a hoax like that today, it would last all of 10 seconds.

Now, if Piltdown Man was the only piece of evidence of human evolution, the creationists would have a point. Except, it isn’t. The amount of evidence for many of the steps of human evolution since the split from other great apes around 7 million years ago is enormously broad and definitive. There are literally thousands of books that accurately describe human evolution. Here’s my personal favorite: Human Origins: What Bones and Genomes Tell Us about Ourselves.

Unless you believe that one hoax is indicative of a culture of fraud and deceit in evolutionary biology, which is probably a belief of all evolution deniers, then this story is what it is–an isolated attempt for fame and fortune that was shot down rather quickly (with intervening wars, economic depressions, and the lack of technology) by real science.

Science said smoking is healthy!

Here are another one of those tropes used by the anti-vaccine crowd mostly. They use it to discredit “science,” attempting to imply that if these so-called scientists thought that tobacco was healthy, then how can we trust them to say the same thing about vaccines. Or GMO’s. Or cancer treatments. Or climate change. Apparently, this myth is shared at the aforementioned meeting of pseudoscience supporters in Sedona, Arizona.

But really, did any real scientist claim that smoking was healthy? Smoking tobacco was prevalent in the native American tribes well before the advent of modern science. There was no Native American CDC, FDA or Board of Physicians to approve the use of tobacco as “safe and effective.”

In fact, those Native Americans and Europeans who picked up the habit believed in all kinds of nonsense about tobacco, including that it cured cancer. This wasn’t “science” pushing these beliefs, but it was the traditions of the world at the time that put inordinate faith in various herbs and how they could cure various maladies. In fact, thinking smoking or tobacco was healthy was advertised by the woo-pushers of the time, who are barely different than the woo-pushers of the modern world (see Note 3).

By the late 1800’s, when real evidence-based medicine was in its infancy, many British journals were publishing articles warning about some of the negative health effects of smoking. An article in The Lancet in 1913 warns “that tobacco smoking can give rise to constitutional effects which diminish the resisting power of the body to disease” (see citation below since this 1913 article lacks an inline citation).

By the 1930’s, real science observed the increase in lung cancer from smoking. The Nazis banned cigarette smoking in the 1930’s because of the known health effects (and that will be the last time I will mention Nazis in any positive sense in anything I ever write again).


Yes, tobacco advertisers used to make ads that showed doctors smoking, or worse, endorsing cigarettes. But that wasn’t the “science” of the time. Big Tobacco (a truly evil lot of characters) said just about anything to get people to smoke, whether it was showing doctors smoking or that smoking made you sexy. But they weren’t using peer-reviewed science, these ads were worse than anecdotes because they were outright lies and mischaracterizations. Science had already concluded that cigarettes were unhealthy a half century before those ads. And don’t forget that most of those “doctors” endorsing cigarettes were, in fact, actors.

Once real epidemiological studies were published in peer-reviewed journals, the attitude about smoking changed almost immediately in the medical and general scientific community. If there ever was a scientific consensus that smoking was safe (and I can’t find real evidence of that ever happening), it eventually self-corrected over a short period of years.

So if you think that “scientists pushed tobacco,” nothing could be further from the truth, unless you want to accept the advertising from Big Tobacco as some sort of truth. And it was real science that found the link (when modern epidemiology really developed as a discipline), and it was real science that became the basis of the worldwide effort against smoking.



The myths about DDT

What about DDT? For a little background, DDT is a powerful insecticide, invented by Swiss chemist Paul Hermann Müller, who was awarded the Nobel Prize in Physiology or Medicine in 1948 “for his discovery of the high efficiency of DDT as a contact poison against several arthropods.” OK, I’m going to concede that a real scientist invented DDT.

But, there is much more to the story. The chemical was used extensively during World War II by the Allies, in both the Pacific and Europe, to control the insect vectors of typhus, dengue fever, and malaria, nearly eliminating the disease in Europe. DDT was spectacularly successful in eradicating these diseases in Australia, the South Pacific, South America and other areas of the world after WWII. At the time, the goal of defeating those diseases far exceeded any risk known at that time.

However, if you think those mythical science wizards were standing in their Dark Tower waving their wands of power suppressing all other knowledge of DDT, you would be wrong. Early data about the harmful effects of DDT was known by scientists (I guess not the ones standing in the tower), and by 1950, the US Department of Agriculture, which had jurisdiction over insecticide use at the time, were beginning to establish regulations to limit DDT’s use.

By the early 1960’s, upon publication of Rachel Carson’s book, Silent Spring, which described some scientific, but mostly anecdotal evidence that DDT had harmful and long-lasting effects on the environment, the tide turned against DDT and it was mostly banned or strictly controlled by the late 1960’s.

Today, DDT is still used because it is still an effective means of controlling certain insect vectors, especially in areas where governments cannot afford more expensive insecticides or the latest medical treatments, especially for malaria. It is through the scientific method that real scientists determined the potential environmental dangers of DDT, but also on how to use it safely where alternatives are costly.

No matter what we think of DDT now, it was responsible for saving millions of lives. Science isn’t black and white – it is clear that DDT saved lives according to scientific research, and it is clear that DDT has a significant environmental impact, again, according to scientific research. Those are competing interests on a mega-scale. In a balanced and nuanced discussion about DDT, there are two sides of the story: one side is saving lives, and on the other, an environmental disaster.

But science has discovered new technologies for mosquito control, like the innovative Frankensquito, where we might get both environmental safety and protecting humans. But more than that, real science is looking for a better solution, whether it’s safer insecticides or vaccines to protect individuals against malaria and dengue fever.

Of course, some may argue any damage to the environment is unacceptable but is there not a similar cost-benefit calculation to save lives from malaria, dengue fever or other insect vector diseases? What if you’re in a country where malaria is endemic and can be destroyed cheaply and effectively with DDT, but the application is managed in a way to limit the environmental damage? Is that not an acceptable tradeoff?

So, sure, science gave us DDT, but it saved millions of lives before science itself discovered that it might have some negative effect on the environment. Scientific principles change as it accumulates evidence, and that’s a good thing. Being dogmatic is not science, and that’s what makes it powerful

Scientists said thalidomide was safe!

Well, they never did, but this is a prime example of the poisoning of the well fallacy, which abounds throughout the antivaccination cults. There are numerous tired, hackneyed myths about the drug thalidomide, which, in the 1950’s was marketed by a German pharmaceutical company for the treatment of morning sickness in pregnant women (as one of its many indications).

At that time, medications were not as strictly controlled as they are today for use during pregnancy, and thalidomide was given out rather freely to pregnant women to some parts of the world. Unfortunately, nearly 10,000 children (half of them born in the former Federal Republic of Germany, also known as West Germany, but none in East Germany, because the communists did not approve it for use) were born with birth defects as a direct result of using the medication.

Here’s an important point. Despite significant pressure from politicians and Big Pharma, the FDA, as a result of the actions of a top scientist there, Dr. Frances Oldham Kelsey, blocked approval of thalidomide in the USA, because it did not have the testing that proved it was not dangerous to the fetus.

So you can invent whatever myth you want, but science had issues with thalidomide, and Dr. Kelsey was smart enough and strong enough to make sure that Americans didn’t get the drug. Because many other countries follow the lead of the US FDA on drug regulations, many other countries blocked its importation.

Even though Dr. Kelsey knew that there wasn’t any evidence that the drug was safe for pregnancy, it caused a sea change in both the independence of the FDA from congressional interference, but also in the amount, complexity and quality of research that must be done before a drug can be approved by the FDA.

Dr. Kelsey spent over 45 years at the FDA (only retiring in 2005, and passing away in 2015) pushing scientific analysis of medications, which lead to the greater safety of medications. She was one of the heroes of modern medicine for standing up for better drug testing. And saving a lot of American babies from birth defects.

Despite the tragedies from the 1960s, thalidomide is not laying on the waste heap of failed drugs. It is part of the standard treatment for leprosy, a horrible disease in many parts of the world.

And because of our understanding of how thalidomide did harm the developing fetus, scientists began to examine its power in treating other diseases. For example, thalidomide is part of the chemotherapy regimen that is used to treat multiple myeloma, a type of cancer of plasma cells. Modern treatments, which include thalidomide, has increased survivability from 3-4 years by almost double to 5-7 years or more. So if you’re going to invent a vacuous strawman argument, trying to poison the well about pharmaceutical companies and the FDA, you might want to avoid using thalidomide as your example.

Science mistakes – sure it isn’t perfect

Science is not perfect, and no scientist would make that claim. There are many examples regarding science mistakes, but the great thing about science is that it is self-correcting as evidence is gathered.

People think that “science” is a magical word with some magical properties, but it is, at its basic level, a logical method to find evidence to answer a question. But until such time science is performed by unfeeling robots, it is a human activity, wracked with errors of human intellect, bias, and random mistakes. As science accumulates evidence over time, the theories and principles established by the evidence become closer and closer to a scientific fact.

Science has always been open to criticism and analysis, in fact, part of developing those theories and principles is to provide evidence in the most transparent manner possible, and then stand in front of your peers for hostile and critical questions. No real scientist could get away with a claim that “smoking is healthy” today because there would be a hundred scientists jumping on it, and showing the contrary evidence.

We have high-quality open source journals that publish information quickly (still heavily peer-reviewed), so that claims that don’t make scientific sense get smashed out of existence quickly. As opposed the misinformation pushed by pseudoscientists, scientific evidence is based on the quality and quantity of evidence. That’s why we know that evolution is a fact, anthropogenic global warming is a fact, HIV causes AIDS is a fact, and vaccines being safe and effective are a fact.

The four examples used here, Piltdown man, thalidomide, smoking, and DDT, are really ancient news, given how fast science moves today.

Sometimes, when we invent criticisms of science, we forget about all the great successes of science, which vastly outweigh the mistakes. For example, vaccines have nearly eliminated most infectious diseases (sorry vaccine deniers, but you just have no scientific standing to say anything else; even evolution deniers accept vaccines).

We have computers and phones that allow you to read my article 5 seconds after I publish it. We’ve explored Mars and landed on the moon. We understand the beginnings of the universe. I’m incapable of reading maps, but thanks to GPS systems I never get lost, thank you science. I can’t even list the billions of things that make your life better, just because of science.

So cherry picking a few errors of science (if I were an anti-science person, I would have focused on some real winners, like canals on Mars, or using an ultra-high speed drill to open calcified atherosclerotic lesions) just to confirm your cognitive biases about science. It does not provide support for your pseudoscience belief. It just makes you look foolish. Moreover, for every “mistake” you can find about science, I can easily show you that it was real science that uncovered that mistake.

Emily Willingham, in an article in Forbes, wrote the following about science:



Only in an imaginary world would anyone think that science is perfect. But in this real world, science makes our lives better in innumerable ways. My life has been devoted to science, and I have made more mistakes doing it than you can ever believe, but in the end, what I have done in the pursuit of scientific knowledge has helped my fellow man in direct, quantifiable ways.

I think that’s what science does best, it helps mankind, both directly and indirectly. And finding a few errors along the way? That’s just part of the process. And all of you should be thankful that the process self-corrects, or you wouldn’t have that computer that allows you to read my words. Or detect cancer. Or guide a spacecraft 100 million km (give or take a couple of km) from the Earth to Mars.

TL;DR – science mistakes

  • Science isn’t magical
  • Science is a logical, rational process to discover evidence to support our understanding of the natural universe.
  • Science is harshly self-critical and is self-correcting over time
  • Science isn’t perfect
  • Science didn’t support DDT, smoking, thalidomide, and the Piltdown man. In fact, real science uncovered the evidence that involved those myths.

Let’s remember, the scientific consensus is based on the accumulated evidence derived from the scientific method published in peer-reviewed journals. It doesn’t rely upon one single piece of evidence, cherry-picked from an obscure predatory journal.

Unfortunately, there are many reasonable people who don’t understand science. This probably results from the fact that science is hard and requires a lot of time and effort to do it well. I am a scientist by profession, yet my area of expertise is a tiny sliver of all science. I hated physics in college, and I still hate physics, so I claim no expertise in it. But I know there are experts in the field who have spent the time to appreciate it and understand it, and who have mountains of evidence to support their scientific consensus. That’s why I do not doubt the Big Bang, even if you asked me to explain it, I would flunk.

My friend Dorit Rubinstein Reiss has stated that the issue with science denialism is often not related to ignorance, but more to arrogance. The internet has empowered people to think they are epidemiologists, medical doctors, lawyers, or astrophysicists. As a specialized scientist, I don’t presume that. I’ve got tens of thousands of hours (see Note 4) in research of diabetes, and it makes me laugh (and angry) when I see some amateur try to tell someone how they can treat type 1 diabetes.

When I’m not an expert in an area, I don’t pretend that I am. I rely on experts who do have evidence supporting their position. Dr. Paul Offit is one of the world’s leading experts on vaccines and infectious diseases, who has spent thousands of hours studying and researching vaccines and pediatric diseases. He is by any definition an authority in vaccines. Yet, in a fit of arrogance, people who lack any expertise or evidence to support their beliefs, dismiss Dr. Offit with a wave of the hand and disgusting ad hominem personal attacks.

Although Google can be empowering for knowledge, we need to quit being arrogant that a few hours of biased research is somehow equivalent to getting a bachelor’s degree in a scientific discipline, then getting a Ph.D. studying a tiny sliver of science for 4 or 5 years, then spend another couple of decades in research. But even that doesn’t matter – it’s the quantity and quality of evidence that supports their authoritative statements.

We should respect science, not dismiss it with logical fallacies and poor quality data. I can only hope.


  1. Science doesn’t “prove” anything. It’s a semantic point that needs to be stressed in this article. Proving something implies certainty, and as I described, science is provisional. Further robust evidence could change the outcome or conclusion. Mathematics has proofs because many mathematical theorems rely upon certainty. Science hasn’t proven that vaccines are safe and effective, it’s just not within the bailiwick of science. On the other hand, science can provide overwhelming evidence that supports the conclusion that vaccines are relatively safe and effective.
  2. The anti-vaccine religion often demands unscientific studies as “proof” that vaccines are safe or effective. They want double-blinded clinical trials as that proof. Unfortunately, there are a lot of issues with clinical trials in vaccines, and that is that the study design would put the control group in harm’s way. That is considered unethical, and no institutional review board would agree to support such a study. This is a more complicated issue that can be represented in one paragraph, so stay tuned for a future article. In addition, large case-control and cohort epidemiological studies can be nearly as powerful, if not more so.
  3. This kind of puts a bit of perspective on “traditional herbal remedies” because much of the evidence for their usefulness is based on oral tradition which is a recounting of anecdotes rather than clinical trials.
  4. I focus on “hours” of expertise quite a bit. I am influenced by Malcolm Gladwell’s book, Outliers: A Story of Success, wherein Gladwell stated that to become a world-class authority on any topic requires 10,000 hours of study and experience. I think in science, you may want to double or triple that.

Editor’s note: This article was originally published in August 2014. I wanted to update it with some serious copyediting, some serious link updating, some serious formatting, and some serious spline reticulating.

Key citations:


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The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor