Science matters because it works

Why should you support science? Because it works! It’s crazy to me that I even have to say that, but this is where we are as a society. Various forms and degrees of science denial are running rampant throughout our culture, and attacks on science are being disseminated from the highest levels. Indeed, it has gotten to the point that hundreds of thousands of scientists and science enthusiasts like myself feel compelled to take to the streets to march for science and remind everyone of the fundamental fact that science works and is unparalleled in its ability to inform us about reality and improve our world.

Image via the CDC

Just look around you. Everything that you see was brought to you by science. The batteries that power your electronic devices are a result of scientific advances in chemistry, as are the plastics that make up seemingly everything in our modern world. The planes that let you travel the world in mere hours were produced by our understanding of physics. The medicines that have doubled the human life expectancy came from biology, physiology, etc. Diseases that once claimed millions of lives each year are now almost unheard of thanks to advances in immunology, virology, etc. Even on topics where people frequently criticize science, like cancer, there have been great advances. Our ability to fight many cancers is improving, and, at the risk of appealing to anecdotes, I personally have family members who recovered from cancers that were untreatable just a few decades ago. Indeed, everyone reading this probably has friends and family who are only alive because of modern medicine (in fact, I would have died as an infant if it were not for medical technologies that my ancestors couldn’t dream of). Our entire modern world only exists because science works. Medicine, computers, cell phones, satellites, plastic, etc. all exist because science works. That is why it is so incredible to me that the anti-science movement even exists. Science has a proven track record, and we all benefit from it constantly.

Nevertheless, here we are, in a reality where the most powerful man in the world refers to an extremely well-established scientific fact as a “hoax,” a world where countless celebrities go around promoting all manner of unscientific woo, a world where opposing science has become a fashionable status symbol, a world where even a notion as ridiculous as believing that the earth is flat can enjoy a resurgence of popularity. This is crazy, and it has to stop. If we want to move forward as a society, or even just maintain our current position, we have to embrace science, not oppose it. Our views and policies have to match the facts, rather than trying to make the facts match our ideology.

Now, at this point, inevitably lots of people are going to get offended and respond with something to the effect of, “I’m not anti-science, but…I disagree with the way that science is being done, I think that massive corporations are buying off scientists, I have anecdotes that don’t match the science, scientists have been wrong in the past, scientists are close-minded, etc.,” but those aren’t valid responses and by using them you are standing in opposition to science, which makes you, by definition, anti-science. See, here’s the thing, science is a method, and it either works, or it doesn’t. You can’t pick and choose when you want to accept it and when you want to reject it. Either you accept that science is the only reliable method for understanding our universe that we have ever come up with, or you don’t.

This brings me to two important points. First, the people who make, “I am not anti-science but…” arguments are nearly always people with zero experience in science. They are people who are projecting their distorted preconceptions about science onto a method that they know nothing about. When people saying things like, “climate change scientists are just in in for the money” or “scientists are just going along with the dogma of their fields” they are just revealing how little they actually understand about how science operates or why we do research. No one gets funding for blindly going along with something that everyone already knows. You get funding for pushing boundaries and chasing novel ideas. Indeed, every great scientist was great precisely because they discredited the views of their day.

that's not how this works memeSecond, these arguments nearly always (I’m tempted to say always) arise when science conflicts with someone’s personal beliefs. For example, countless conservatives are happy enough to have science make more efficient batteries, predict tomorrow’s weather, cure their illnesses, etc., but the instant that it says that burning fossil fuels is bad, suddenly they turn on science and invent fanciful conspiracies, appeal to a minority of fringe researchers, cite discredited papers, etc. Conversely, droves of people stand behind the science of climate change 100%, but when exactly the same scientific method says that GMOs are safe, suddenly we are back in conspiracy land. That’s not how this works! You don’t get to oppose science just because it shatters your naïve ideology. When thousands of papers conducted by countless scientists from all over the planet arrive at the same conclusion, you don’t get to reject that conclusion just because you don’t like it.

A final group of dissidents take things even further and directly question the validity of science. They claim that decades of research on vaccines is discredited by the simplistic notion that “mothers know best.” They ignore the scientific impossibility of homeopathy in favor of personal anecdotes. They insist that the fact that something has been used for thousands of years is more important than the fact that numerous studies have shown that it’s nothing but a placebo, and they embrace all manner of utter nonsense about energy fields, crystals, resonant frequencies, etc.

All of this is, however, once again, discredited by the obvious fact that science works! We had anecdotes, appeals to antiquity/popularity/nature, maternal instincts, etc. for thousands of years, and they got us nowhere! Science is the thing that allowed us to tell which of those anecdotes were based on causal relationships and which ones were based on spurious correlations, and science is the thing that allowed us to know which natural remedies actually worked (e.g. aspirin) and which ones were hogwash. Further, science is the thing that let us improve on nature and synthesize purer and more concentrated forms of natural chemicals, as well as making medicines that aren’t even found in nature. Again, the evidence for this is everywhere! If you have diabetes and take insulin, for example, you get that insulin not from nature, but rather from a GMO that was produced by science. Similarly, if you need surgery, I’ll bet anything that you are going to want to be knocked out using the best anesthetic that science has to offer, rather than munching on some herbs. Again, science is a method, not a collection of information, and the method clearly works.

The history of tobacco actually illustrates this well. It was used medicinally for centuries by Native Americans, it was supported by countless anecdotes, it was 100% natural, mothers thought it was best for their children, etc. Today, however, we know that not only does it fail to cure illnesses, but it is extremely carcinogenic. Why do we know that? Because of science! Because careful and systematic studies revealed that all of those anecdotes, maternal instincts, etc. were wrong. Now, someone is surely about to write a comment about the time that scientists were paid off by Big Tobacco to support smoking or the doctors who thought smoking was safe, but those are distortions of history. Sure, there was a transition period when evidence was still being accumulated and scientists and doctors were not convinced (nothing in science changes overnight), but that didn’t last, because science prevailed. Similarly, yes, there were a minority of scientists that were paid off, and tobacco companies certainly put tons of money and effort into creating the illusion that there was no scientific evidence that smoking was dangerous, but that was entirely a smoke screen created by the companies, and, once again, their efforts ultimately failed.

Indeed, this is exactly the same thing that is happening today on so many issues. The science on climate change, for example, is extremely clear. It is supported by thousands of studies and is agreed upon by virtually all climatologists. Nevertheless, fossil fuel companies have done a marvelous job of creating the illusion of controversy. They have a handful of scientists that they publicize strongly, and they pour tons of money into promoting the notion that the science isn’t settled. The anti-vaccine movement is the same thing. The science is solid, but they have a handful of “experts” and pump so much money and effort into it that it appears that there is a conflict, even though this is a settled issue among medical experts. Similarly, big organic companies pump untold millions of dollars into opposing GMOs and making it appear that the science isn’t settled, even though nearly 2,000 studies have conclusively shown that GMOs are  safe for humans and no worse (or even better) for the environment than traditional crops. Finally, if you are prone to conspiracy theory musings, then consider this: massive, multi-billion dollar tobacco companies tried as hard as they could to buy of scientists and suppress the truth, but they utterly failed. So how likely do you really think it is that pharmaceutical companies, Monsanto, etc. succeeded at that endeavor?

This post became more of a rant than I had intended, so let me try to rein things back in for a concluding paragraph. My point is simple, fundamental, and obvious: science works. A huge portion of you are probably only alive today because of science, and even if you would have survived, statistically, many of your friends and family members wouldn’t have. Indeed, you benefit immeasurably from science every single day. The advances of the past roughly 150 years are incredible, and they only occurred because of the method known as science. I for one, want those advances to continue, and I certainly don’t want to go backwards, but that means supporting science. It means making it a priority, and it means accepting the results that it produces even when we don’t like them. I usually try not to get political on this blog, but the reality is that if you love the advances that science has produced, then you need to get political. You need to vote based on who supports science, and you need to tell your elected officials that it is not okay to reject science or to cut funding for it, and I’m not just talking about climate change here. If you want life-saving medical breakthroughs to continue, then you need to support funding for agencies like the NIH. If you want to benefit from an enhanced understanding of the universe, then you need to support funding for things like the NSF. If you understand how many technological wonders have come from the space program and want more technological advances, then you need to support funding for NASA. I could go on, but hopefully you get my point. The way that I see it, our society is at something of a crossroads, and either we will fight for science, support it, and move forward because of it, or we will reject it, downplay it, and ignore it, in which case, at best, we will stagnate and halt our progress, and at worst, we will move backwards (e.g., increased disease outbreaks as vaccination rates fall). The choice between those two options seems pretty obvious to me.

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Posted in Global Warming, GMO, Nature of Science, Vaccines/Alternative Medicine | Tagged , , , , , , , , , , | 10 Comments

The vaccine package insert paradox

The anti-vaccine movement presents a beautiful case-study in inconsistent reasoning and logical contradictions. One of the most entertaining and important of these contradictions comes from their treatment of vaccine package inserts. If you have ever spent any time debating anti-vaccers, then you have, no doubt, encountered these inserts. They list adverse events that were reported during vaccine testing, and anti-vaccers are adamant that these inserts provide clear evidence that vaccines are, in fact, dangerous. As I will explain, however, this argument is inconsistent with other core anti-vaccine arguments, and the presence of adverse events in the package inserts actually provides strong evidence against the vast global conspiracy that anti-vaccers envision (and, indeed, that their position requires).

blue stick figure white vaccine package insert paradox anti-vaccerFirst, it is important to clarify exactly what the adverse events on vaccine package inserts actually are, because anti-vaccers constantly get this wrong. They are not side effects that have been confirmed to be caused by vaccines. Rather, they simply include any adverse event that was reported during vaccine testing, regardless of whether or not the vaccine was the cause. For example, if, during testing, a child developed a fever from something completely unrelated to the vaccine, fever would still get listed as an adverse event (remember, saying “A happened before B, therefore A caused B” is a logical fallacy known as post hoc ergo propter hoc). In other words, the package inserts contain a lengthy list of anecdotes, and anecdotes are not evidence of causation. If you actually take a careful look at the lists, you should be able to convince yourself of this pretty easily. For one thing, many of the items on these lists (such as autism) have been carefully studied and repeatedly shown to have no causal relationship with vaccines. Further, the lists contain things like teething, and I doubt that even the most ardent anti-vaccer is willing to blame vaccines for teething (thus we get our first logical contradiction, because they are cherry-picking which adverse events to blame vaccines for). Finally, the package inserts themselves clearly state that the items on these lists have not been shown to be caused by vaccines. So, once again, anti-vaccers are being logical inconsistent because they are only believing the part of the package insert that agrees with their preconceptions. Just to prove that I’m not making this up, here is a quote from the Tripedia DTaP vaccine insert (an insert that anti-vaccers frequently cite; my emphasis).

“Events were included in this list because of the seriousness or frequency of reporting. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequencies or to establish a causal relationship to components of Tripedia vaccine.”

There is, however, a more serious contradiction, and it is the one that I want to focus on. Anti-vaccers insist that “big pharma” knows that vaccines are dangerous and are just covering it up for the sake of money. For that claim to actually work, however, you also need governmental regulatory agencies and pretty much all of the world’s scientists to be willing to cover up evidence of the dangers of vaccines as well. Thus, anti-vaccers are forced to concoct a vast conspiracy in which pharmaceutical companies lie constantly and have bought off the FDA, CDC, independent scientists, etc. Now, if all of that is true, then riddle me this, Batman, why would those lying companies publish a list of adverse events that has to be approved by the corrupt FDA?

Really think about this for a second. In the same breath, anti-vaccers will tell you that Big Pharma is lying to cover up the truth about vaccines and publishing a list that proves that vaccines are dangerous. Those two views are incompatible. If these companies are actually willing to buy off major government organizations and most of the world’s scientists, then why on earth would they undo all of that by publishing a list of harmful things that vaccines cause? (note: even though these lists don’t actually show causation, they are still clearly not in the pharmaceutical companies’ best interests, more on that in a minute)

You might try to worm your way out of this by arguing that Big Pharma doesn’t want to publish these lists, but the FDA forces them to. If that is your response, however, then you are correct that this is what is happening, but you are wrong that it helps your position. You see, if you argue that the FDA is forcing Big Pharma to do this, they you have just undercut the notion that Big Pharma bought off the FDA, and that is a huge problem for you. The FDA demands evidence that things are safe before it will approve them, so the only way that Big Pharma is going to be able to push “TOXIC” vaccines is if they have bought off the FDA, but if they bought off the FDA, then how is the FDA forcing them to publish these lists? Do you think that the FDA is ok with poisoning children just so long as the company prints a list of adverse events on the package insert? That makes no sense.    

A second approach would be to claim that companies are only publishing those lists to avoid lawsuits, but there are two problems with this argument. First, these lists are not standard warning lists, so it’s not actually clear to me that they would do much in a legal setting. Second, and more importantly, the National Vaccine Injury Compensation Program (VICP) was set up precisely so that people could seek compensation for “vaccine injuries” while protecting companies from expensive lawsuits. In other words, companies are already protected from lawsuits by the VICP, so they don’t need a list to do that (note: the VICP is essentially a no fault system that does not require evidence that the vaccine actually caused the injury, so it also doesn’t constitute evidence that vaccines are dangerous; details here).

Finally, you could try to get out of this mess with a shred of dignity by admitting that the lists don’t actually provide evidence that vaccines are dangerous. Although that is certainly the position that you should take, it actually doesn’t help you all that much, because a clear logical contradiction still remains. People respond incorrectly to labels all the time, and companies know this (that is why totally worthless labels like “organic” and “natural” are so common). Thus, even though these lists aren’t actually evidence against vaccines, people will (and clearly do) still view them that way, and pharmaceutical companies aren’t stupid. They know that people will miss-interpret those lists. Thus, publishing those lists is still bad for Big Pharma’s bottom line, which once brings us back to the question of why the companies publish them? I’m actually going to agree with anti-vaccers here, and agree that pharmaceutical companies would be more than happy to cover up anything that might hint that their products are dangerous. I’m under no delusions that pharmaceutical companies are benevolent entities setting out to bring about world peace and eternal youth. They are after money, plain and simple. Their greed is, however, kept in check by regulatory agencies like the FDA. In other words, we have once again arrived at the conclusion that companies publish these lists because the FDA requires them to do so. This is really important because, as I explained above, this is completely inconsistent with the notion that the FDA has been bought off by big companies, and if the FDA hasn’t been bought off by big companies, then you have no reason to think they aren’t actually doing their job and regulating pharmaceutical products.

To summarize all of this, the anti-vaccine movement relies on the notion that companies have bought off regulatory agencies like the FDA, because without that conspiracy, there is no explanation for the fact that agencies like the FDA approve vaccines. However, the FDA forces pharmaceutical companies to publish adverse events in the package inserts, even though doing so is bad for the companies. Herein lies the contradiction. If the FDA has been bought off, then how is it capable for forcing companies to publish these lists? These two things are incompatible with each other, and the fact that the FDA can force companies to publish these lists is clear evidence that the FDA controls the companies, not the other way around. Without a corrupt FDA, however, anti-vaccers’ conspiracy theory comes crashing down.

Posted in Vaccines/Alternative Medicine | Tagged , | 37 Comments

Scientists aren’t stupid, and science deniers are arrogant

Debating those who reject scientific facts has been a hobby of mine for several years now. It’s not a very rewarding hobby, and it comes with high stress levels and periodic fits of rage, so I don’t particularly recommend it. However, it has exposed me to countless pseudoscientific arguments on pretty much every topic you can imagine, and on each of those topics, I have found that not only do people with no formal training in science think that they know more than the entire scientific community, but in almost every case, they think that there is a fundamental and obvious problem that essentially all scientists have either missed or are willfully ignoring. If you think about this for a minute, it’s rather incredible. It’s amazingly arrogant to think that you can, via a few minutes of Googling, find a fundamental and obvious problem that essentially every scientist everywhere in the world missed, despite their years of training and experience. Nevertheless, that is exactly what most anti-scientists think (though they wouldn’t usually put it in those terms). Therefore, my intention is to provide several examples of this type of thinking using arguments from a variety of topics. Hopefully, this will illustrate the absurdity of this type of hubris and demonstrate the key point that I want you all to take home. Namely, if you think that you have found a simple and obvious problem that virtually every scientist on the planet missed, you are almost certainly wrong.

Note: Before I begin, I want to clarify that if you are one of the people who uses these arguments, I do not want you to think that I am attacking or belittling you. As I have previously written about, I used to be one of you. So, if you feel like I am making fun of you, realize that I am also describing my former self. To put that another way, I don’t think that you are stupid, but you are misinformed, and you are behaving irrationally.

This figure from Hansen et al. 2005 shows the effect of both the natural and anthropogenic drivers of climate change. Notice how only anthropogenic sources show a large warming trend. Also, see figure 2 of Meehl et al. 2004.

Let’s begin with climate change arguments. There are many that I could choose from here, but let’s start with the argument that the current warming is just a natural cycle because the climate has changed naturally in the past. If you like to use this argument, then I have several questions for you. Do you honestly think that climatologists never thought of this? Do you really think that the people who spend their lives collecting those data on past climates never even bothered to check and see if the current warming was part of a natural trend? I realize that I probably sound flippant here, but I’m actually asking these questions sincerely. Do you truly think that the entire scientific community is so hopelessly incompetent and stupid that they never even bothered to check the natural drivers of climate change? If you do, then I have news for you: they aren’t. Scientists have looked at past climate changes (Lorius et al. 1990; Tripati et al. 2009; Shakun et al. 2012), and they have very carefully looked at the natural drivers of climate change, and they have consistently found that the current warming does not match natural cycles and can only be explained by including our greenhouse gasses in the analyses (Stott et al. 2001; Meehl, et al. 2004; Allen et al. 2006; Wild et al. 2007; Lockwood and Frohlich 2007, 2008; Lean and Rind 2008; Foster and Rahmstorf 2011; Imbers et al. 2014).

A very similar argument proposes that the sun is the cause of climate change, and I have frequently encountered people who seem to truly think that scientists have never examined that possibility. Again, how stupid do you think scientists are? Do you really think that it never occurred to any of them that the giant nuclear furnace in the sky might be the problem!? News flash, it did. They’ve studied the sun’s output repeatedly and have consistently found that it is not the main driver of our current climate change (Meehl, et al. 2004; Wild et al. 2007; Lockwood and Frohlich 2007, 2008; Lean and Rind 2008; Imbers et al. 2014).

Similarly, climate contrarians love to point to the Antarctic sea ice and say, “the sea ice is increasing, so global warming can’t be happening.” Again, do you really think that scientists aren’t aware of that fact? Do you honestly think that thirty seconds on Google showed you a fact that the entire scientific community is ignorant of? Or, if they are aware of it, then what, are they just too stupid to comprehend it? There’s really only three possibilities here, and they are all nuts. To think that scientists have somehow missed this or are ignoring it, you have to think that all scientists are either stupid, hopelessly ignorant, or involved in some form of insane and enormous conspiracy. The more rational conclusion, however, is clearly that the situation must be more complex than a simple increase in sea ice would lead you to believe, and scientists must have information that you didn’t uncover via your degree from Google University. That is, of course, reality. For one thing, although Antarctic sea ice had increased (see note), ice shelves and glaciers globally are down and we keep setting new record highs for annual average temperature (WGMS 2013; Parkinson 2014; Stroeve et al. 2015). Further, when you look more closely at the situation with the Antarctic sea ice, you’ll find that it is being caused by a complex combination of factors including the levels of ozone in the atmosphere, shifting ocean currents due to ice melting elsewhere, etc. Gillett and Thompson 2002; Zhang 2007). My point is that these simple, obvious arguments almost never work. Reality is more complex than that.

Note: At the time of writing this, Antarctic sea ice was actually unusually low, but that is likely just a fluctuation, and it is too early to draw any solid conclusions. Thus, it may return to being high in the near future. Nevertheless, there is a very consistent global trend of decreasing ice.

we did not evolve from apes but we share a common ancestor with themClimate change deniers are, of course, not alone in their hubris. Creationists are right up there with them. Probably one of the most common examples of this type of flaw from creationists is the classic argument, “if humans evolved from apes, then why are there still apes?” As with the climate change arguments, I have to ask, do you honestly think that scientists are this stupid? Just think about this for a second. If this argument actually worked, then it would mean that basically every biologist for the past century missed an extremely obvious problem. To fully comprehend just how crazy that is, realize that we are talking about people who spent close to a decade receiving intensive training in biology and then spent the rest of their lives actually doing biology. You really think that in all of that they somehow missed the fact that humans and apes are both still around? Do you really believe that despite years studying every detail of fossils, constructing and comparing cladograms, etc. they never stopped to think about the fact that apes are still here? Do you honestly think that they are going to have their entire life’s work brought crashing down by a simple 11 word question? Does that seem rational to you? It shouldn’t. The reality is, of course, that this argument is a strawman fallacy. Evolution tells us that modern apes share a common ancestor with us, rather than us evolving from them. So, it is the creationists who missed something obvious and fundamental, not the scientists (to be fair, some creationist organizations do eschew this argument, but it is, nevertheless, common among the general public).

Another common creationist argument is the claim that evolution defies the laws of thermodynamics because those laws say that things constantly become more disorganized, whereas evolution says that things become more organized. Here again, do you honestly think the Google has endowed you with a better understanding of thermodynamics than people who spend their entire lives studying it? Do you really think that every scientist in the world is so fundamentally wrong about an extremely basic concept in science? And let’s be clear, here (and in the other arguments) you aren’t just saying that they are wrong, you are saying that they have all missed an extremely obvious, elementary problem that a high school student could see. That’s crazy. Once again, reality is far more rational, because reality tells us that systems are only required to become more disorganized when they are closed (i.e., when they aren’t receiving energy from other sources), but the earth is an open system (i.e., it gets energy from the sun) so things on it can, in fact, become more organized (that’s why trees can grow, you developed from a simple, single-celled zygote, etc.; details here). So, once again, it is the science deniers who are missing something obvious and fundamental, not the scientists.

Finally, this post certainly wouldn’t be complete without at least one example from anti-vaccers. I thought a lot about which argument to use here out of the many that I have to choose from, but I think for the sake of this post, the best example is the argument that vaccines aren’t effective because during many (but not all) outbreaks, most of the people who get the disease are vaccinated against it. As with every example that I have given, at a quick glance, it sounds like a really good argument. It seems like a slam dunk against vaccines, but if you think about that for five seconds, that should bother you. If this is such clear evidence that vaccines don’t work, then why haven’t any scientists or doctors paid attention to it? Why aren’t the people who publish these statistics concerned by them? Again, if you found this with a few minutes on Google, then why isn’t the scientific community aware of it? Or if they are aware of it, why don’t they care? The answer isn’t conspiracies, Big Pharma, or lizard-people. It’s simply that scientists are better at math than anti-vaccers are. It is true that in many ourbreaks (again not all), most infected people were vaccinated, but that is only because most people were vaccinated. When you look at the actual proportions, you consistently find that the disease rates were much higher among the unvaccinated. To give an analogy, most car accidents involve sober drivers, but that doesn’t mean that driving drunk is safer. Rather, it is a simple by-product of the fact that most people drive sober. When you look at the proportions, you find that the rates of car accidents are higher among drunk drivers.

I could continue to give many other examples both from these topics and pretty much every other “debated” topic in modern science, but I think it would be more profitable to spend the remainder of this post dealing with the counter arguments that I expect to receive. All of these are ones that I have dealt with in the past, so I will be brief here and will simply direct you to my other posts for more details.

First, you may be tempted to accuse me of an appeal to authority fallacy. However, there is a huge difference between appealing to authority and deferring to experts. I’m not saying that these things are true because scientists say that they are (that would be fallacious). Rather, I am trying to get you to engage in a simple exercise in plausibility. Ask yourself, does it honestly seem reasonable that untold millions of people with advanced degrees, years of training, years of experience, scores of publications, etc. missed something fundamental and obvious that you were able to find on Google? No, it doesn’t. Again, that doesn’t automatically make the scientists right, but it should make you very, very cautious about saying that they are wrong. It should give you great humility, and you should fact check extremely carefully using really good sources before you conclude that you are right and essentially every scientist in the world is wrong. To put that another way, you don’t need to be an expert to think that experts are right, but you do need to be an expert to think that they are wrong.

the fact that scientists wrong past conspiracy laughet atNext, you might try to say something like, “well, scientists have been wrong in the past” (debunked here) or “they laughed at Galileo, but he turned out to be right” (debunked here). There are numerous problems with this, so see my other posts for details, but I’ll give a Cliff Notes response here. First, scientific concepts have been discredited before, but they have always been discredited by other scientists doing real research. Second, most of the examples of scientists being wrong come from well before modern science even existed. If you limit yourself to the last 150 years or so (i.e. the age of modern science), you will find far fewer examples of a widely accepted concepts being discredited. Third, when those concepts were discredited, it wasn’t by some simple and obvious thing that everyone except for non-scientists were hopelessly ignorant of. It’s always been something complex or non-intuitive or usually both. It’s been something that had to be revealed by careful research, not an 11-word question. It’s never been something like scientists not bothering to check if the sun is driving climate change. To illustrate this, the Newtonian concept of gravity is one of the best examples of something that was widely accepted in the modern scientific era that turned out to be wrong, but that was discredited by the amazingly complex concept of relativity! Further, Newton wasn’t wrong so much as incomplete (as usually is the case).  Another good example is the concept that continents are stationary. This was replaced by plate tectonics, which, again, is neither obvious nor simple. Finally, it is worth mentioning that the days of a lone maverick operating outside of the norms of science are long gone. Modern science is an incredibly collaborative process, and new paradigm-altering conclusions come from teams of scientists with years of research, not someone sitting on their couch watching Youtube videos.

conspiracy theory skeptic science expertAt this point, you might contend that scientists are fully aware of these problems and are just covering them up for the sake of money, but that is insane. Arguing that essentially all of the world’s millions of scientists are involved in some sort of massive conspiracy is downright idiotic. I’ve talked about the math behind this before, but, in short, there is no motive in most cases (a lot of research is done by independent scientists), and just the sheer size of the conspiracy makes it implausible (it would have to involve every government, every health organization, every scientific body, and every university on the planet). Further, this argument is 100% an assumption. The burden of proof is on you to provide actual evidence that the world’s entire scientific community is corrupt, and unless you can do that, this is an ad hoc fallacy.

As a final attempt at a counter-argument, you might appeal to “dogma’ in science, and claim that there are scientists who see the problems but don’t speak out for fear of ridicule from their peers. This is, however, a complete misunderstanding of how science works. No scientist has ever been considered great for going along with the accepted wisdom of their day. Every great scientist was great precisely because they discredit the accept views of their day. To put that another way, for me personally, as a young biologist, nothing could possibly be better for my career than disproving evolution. If I actuaindiana jones fortune and glory kidlly had simple and compelling evidence that it was wrong, I could publish in any journal of my choosing, I would have my pick of universities to work at, and I would almost certainly receive a Nobel Prize. Disproving evolution would result in me going down in history as one of the great minds of the 21st century. So, why haven’t I or any of the thousands of other ambitious young biologists published that evidence? Because it doesn’t exist! This idea that you have to blindly go along with the “dogma” to get anywhere in science is totally backwards. You don’t get grants to confirm things that everyone already knows. Rather, you get grants, fame, and recognition for pushing boundaries, studying new ideas, and discrediting commonly held views. That’s how you achieve fortune and glory in science.

I find it baffling that so many people think that scientists are arrogant simply because scientists claim to know more about science than non-scientists.

My point in all of this is really quite simple. When you approach any scientific topic, you should do so with an appropriate amount of humility as well as an appropriate amount of respect for the fact that thousands of people spent their entire lives studying a topic that you are only learning about through Wikipedia. Anytime that an argument requires you to think that the entire scientific community is hopelessly stupid, ignorant, incompetent, etc. you should be extremely skeptical. Scientists aren’t stupid, and if you think you have found something simple and obvious that all of them have missed, you are almost certainly wrong. It is the epitome of arrogance to think that a few minutes or even hours on Google have endowed you with a better understanding of science than the collective scientific community gained through countless years of training and experience.

Literature Cited

  • Allen et al. 2006. Quantifying anthropogenic influence on recent near-surface temperature change. Surveys in Geophysics 27:491–544.
  • Foster and Rahmstorf 2011. Global temperature evolution 1979–2010. Environmental Research Letters 7:011002.
  • Gillett and Thompson 2002. Simulation of recent Southern Hemisphere climate change. Science 302:273–275.
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The fallacy fallacy: Reject the argument not the conclusion

Two weeks ago, I wrote a post on the importance of understanding logical fallacies, and in that post, I made the following claim, “anytime that an argument contains a fallacy, that argument must be rejected.” Much to my surprise, many people took issue with this and brought up the fallacy fallacy (that’s not a typo). Some of those comments were simply pointing out the existence of the fallacy fallacy (which I actually did in the aforementioned post as well), but many of them were arguing that I was wrong or at least on shaky ground because of the fallacy fallacy. For example, one person said, “of course simply pointing out that someone’s argument is a fallacy is a fallacy in and of itself,” another said that although I was not committing a fallacy fallacy I was, “flirting with encouraging individuals to commit ‘the fallacy fallacy’” (those are exact quotes, not paraphrases). Thus, it appears that this topic may not be very well understood, so I want to spend this post talking about it, because it is an important concept to grasp. My original statement was correct and in no way misleading. Any time that an argument contains a logical fallacy, that argument is flawed and you must reject that argument. However, it is possible to have a flawed argument that still has a true conclusion. So, the fallacy fallacy only occurs when a bad argument leads you to reject the conclusion rather than the argument.

Logical fallacies are indeed disturbing.

As I explained in the previous post, deductive logical arguments should be set up such that if the premises are true, then the conclusion must also be true. In other words, the conclusion must follow necessarily from the premises (an argument with this property is known as a “valid” argument). However, logical fallacies often present an invalid logical structure in which the conclusion does not follow necessarily from the premises (in other cases they may operate by doing things like assuming false premises). Thus, logical fallacies are errors in reasoning and result in arguments that either aren’t valid or aren’t sound (a sound argument is one that is valid and has only true premises). Therefore, anytime that an argument contains a fallacy, the argument itself is flawed. The logical structure does not work, and you simply cannot use that argument in support of the conclusion. This is fundamental and vitally important to understand: you must always reject a flawed argument. If an argument contains a fallacy, then the argument does not work, and you cannot use it. However, that does not necessarily mean that the conclusion is false.

This is where fallacy fallacies come in. If you tell someone that their argument is wrong because it contains a fallacy, then you are adhering to the rules of logic and have not done anything wrong. However, if you tell them that their conclusion is wrong because the argument contains a logical fallacy, then you have committed a fallacy fallacy, because a bad argument tells you absolutely nothing about the conclusion.

Let me illustrate this using an example from the previous post. The following argument is not valid because it contains an affirming the consequent fallacy.

  • Premise 1: All men are mortals
  • Premise 2: Socrates is a mortal
  • Conclusion: Therefore, Socrates is a man

This is a bad argument. Because of the affirming the consequent fallacy, the conclusion does not follow necessarily from the premises (i.e., not all mortals are men). Thus, we must reject this argument. We simply cannot use this argument as a reason for thinking that Socrates is a man, but in this case, the conclusion is still true. Indeed, if you think about this, you should realize that it is always possible to construct a bad argument for a true conclusion. For example, I could say,

  • Premise 1: Aliens hate goats
  • Premise 2: Aliens like waffles
  • Conclusion: Therefore, the earth is spheroid

That argument is clearly nonsense. It doesn’t make the slightest bit of sense (it’s a non-sequitur fallacy) and both premises are rather bizarre assumptions, but the conclusion is still true! Nevertheless, although it is possible to have a bad argument and true conclusions, in many cases bad arguments do, in fact, lead to false conclusions (see previous post). In contrast, a sound logical argument guarantees that the conclusion is true. So, I reiterate that flawed arguments (including ones that contain logical fallacies) tell you nothing whatsoever about the conclusion. They provide you with absolutely zero evidence for or against it.

So, what does all of this mean practically for you? How should you deal with this in debates? Well, that really depends on whether or not the burden of proof is on you. Remember, the person making the claim is always responsible for providing evidence for that claim, whereas the other person is under no obligation to refute that claim (at least until actual evidence has been provided). So, let’s imagine first that you are not the one making the claim, and the burden of proof is on your opponent. Further, they claim that X is true because of argument Y (in other words, they are using argument Y to support conclusion X). However, you discover a logical fallacy in argument Y. At that point, you should point out that fallacy and reject argument Y, however, you should not make any claims about conclusion X without first introducing other evidence/arguments (more on that in a minute). In other words, the fact that argument Y is flawed tells you nothing about conclusion X, but because the burden of proof is not on you, you aren’t required to do anything else. They have to provide a new line of evidence/reasoning to demonstrate that conclusion X is true, and you are not obligated to accept X or take it seriously until they present that evidence.

Nevertheless, you may have evidence showing that conclusion X is in fact false, in which case, you are welcome to present that evidence and use it to refute X. In other words, saying “argument Y contains a fallacy, therefore conclusion X is false” is a fallacy fallacy, but there is absolutely nothing wrong with saying, “argument Y has a fallacy and, therefore, does not support conclusion X, however, we can tell that conclusion X is false because of argument/evidence Z.” In other words, you can (and indeed should) point out logical fallacies to demonstrate flaws in your opponents’ reasoning, but if you want to actually say that their conclusions are wrong (rather than simply that their arguments are wrong) then you have to present actual evidence to the contrary.

This brings me to the final scenario: situations where the burden of proof is on you. In these situations, you are making the claim and, therefore, it is your duty to present actual evidence. As such, if your opponent points out a logical fallacy in your argument, you must reject that argument and either present new evidence/reasoning or admit defeat. They are not obligated to disprove your conclusion, and you cannot continue to use the flawed argument. Thus, you are obligated to present a new, sound argument and real evidence in support of the conclusion.

In short, any time that an argument contains a logical fallacy, you must reject that argument. I stand by that initial claim. However, the presence of a fallacy (or other problem with the argument) tells you nothing about the conclusion. Therefore, you must always reject the argument, not the conclusion, otherwise you’re committing a fallacy fallacy. Further, to actually reject the conclusion, you need additional evidence/arguments that show the conclusion to be false.

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The importance of logical fallacies

From the Star Trek TOS episode “I, Mudd”

As anyone who frequents this blog knows, I spend a lot of time talking about logical fallacies. I frequently criticize peoples’ arguments for having them, and I present them as a reason for rejecting particular lines of thought. Nevertheless, many people fail to realize just how important they are, and showing someone that they have committed a fallacy rarely makes them reject their argument. Indeed, I once had someone say, “just because my argument technically contains a fallacy doesn’t mean that the underlying logic is wrong.” In reality, however, that is exactly what it means. Logical fallacies are, by definition, flawed lines of reasoning, and anytime that an argument contains a fallacy, that argument must be rejected. Therefore, understanding logical fallacies is critical for analyzing arguments and holding rational views, and in this post, I want to try to explain why fallacies are so important, how to detect them, and why their presence destroys an argument.

The structure of an argument

All arguments can be broken down into premises and conclusions. The premises are the facts that you are presenting, the conclusion is the thing that you are arguing for, and the goal is to set up the argument such that the conclusion must follow necessarily from the premises. In other words, for an argument to be a good argument, it must be set up such that if the premises are true, then the conclusion must also be true (this is what we call a “valid argument”). Additionally, the premises must, of course, actually be true (when both conditions are met, the argument is said to be “sound”). For now, I want to focus on the requirement that the conclusion must follow necessarily from the premises, but we will come back to the true premise requirement later.

 Note: I am talking specifically about deductive arguments here and throughout this post. There are other types (such as inductive and probabilistic) in which the premises show that the conclusion is most likely true, rather than that it must be true.

 To illustrate how this works, let me use the following example (this is set up in what is known as a syllogism).

  • Premise 1: Bill is larger than Bob
  • Premise 2: Bob is larger than Tom
  • Conclusion: Therefore, Bill is larger than Tom

This is a logically valid argument. In other words, as long as those premises are true, then the conclusion must also be true. There are no other options. If Bill is larger than Bob, and Bob is larger than Tom, then it must be true that Bill is larger than Tom (this example is also an illustration of something known as the law of transitive properties). Importantly, you should note that the underlying logical structure is what matters here. As long as that structure works (which it does), we can replace those premises with any other true premises, and the resulting conclusion will be true (as long as we haven’t changed the underlying structure). In other words, we can reduce this argument to the following logical structure:

  • Premise 1: A is larger than B
  • Premise 2: B is larger than C
  • Conclusion: Therefore, A is larger than C

Now, we can replace A, B, and C with any true facts, and the argument will work. For example,

  • Premise 1: Jupiter is larger than earth
  • Premise 2: The earth is larger than the moon
  • Conclusion: Therefore, Jupiter is larger than the moon


  • Premise 1: A train is larger than an ant
  • Premise 2: An ant is larger than a bacterium
  • Conclusion: Therefore, a train is larger than a bacterium

I could keep going, but hopefully you get the point. It doesn’t matter what premises I use, or how disparate the items in them are. As long as the premises are true and I retain the same logical structure, then the conclusion must be true. Further, if you can find a single example in which this structure and true premises results in a demonstrably false conclusion, then you have shown that the argument’s structure must be flawed. In other words, for a deductive argument, the logical structure must work 100% of the time, or else the logical structure is flawed.

It may seem like I am off topic here, but understanding this is really important, because, as I will explain below, many logical fallacies operate by breaking an argument’s logical structure. In other words, they change the argument so that the conclusion does not follow necessarily from the premises.

Non-sequitur fallacies

Now that you understand the importance of a logical structure, let’s look at a large family of fallacies collectively known as non-sequitur fallacies. These occur anytime that an argument’s structure is such that the conclusion does not follow necessarily from the premises, but there are many specific subcategories and types of fallacies within that overarching umbrella term.

To begin, let’s look at what is probably the most common example in all of philosophy. Consider the following deductive argument:

  • Premise 1: All men are mortals
  • Premise 2: Socrates is a man
  • Conclusion: Therefore, Socrates is a mortal

We can reduce this argument to the following structure:

  • Premise 1: All X are Y
  • Premise 2: Z is X
  • Conclusion: Therefore, Z is Y

That may seem confusing, but if you think about it for a second, you should be able to convince yourself that it will work 100% of the time. If all X are Y, and Z is X, then Z must also be Y.

Now, consider the following extremely similar argument:

  • Premise 1: All men are mortals
  • Premise 2: Socrates is a mortal
  • Conclusion: Therefore, Socrates is a man

An example of an affirming the consequent fallacy

Now we have a problem. This argument does not work. The conclusion does not follow necessarily from the premises, and the reason for that is a logical fallacy known as affirming the consequent. This fallacy alters the logical structure in a way that prevents the premises from leading necessarily to the conclusion. We can write it as follows:

  • Premise 1: All X are Y
  • Premise 2: Z is Y
  • Conclusion: Therefore, Z is X

Again, if you think about that for a minute, you should see the problem. The fact that all X are Y does not mean that all Y are X. Thus, it is possible for Z to be Y, but not X. We can easily illustrate this with an example.

  • Premise 1: All men are mortals
  • Premise 2: My pet iguana is a mortal
  • Conclusion: Therefore, my pet iguana is a man

Obviously, that doesn’t work. It is clearly a bad argument. It has an invalid logical structure in which the conclusion does not follow necessarily from the premises, and, as a result, it produces an incorrect conclusion. Remember, if a deductive logical structure is valid, then it must produce true conclusions 100% the time (when supplied with true premises). Therefore, the fact that my example has an incorrect conclusion proves that this structure is invalid.

Now, what does this have to do with affirming the consequent fallacies? Well that name, “affirming the consequent” is simply the term that we use to describe this logical structure. In other words, by demonstrating that this logical structure is invalid, I have shown that an argument that contains this structure (i.e., that contains an affirming the consequent fallacy) is invalid. This is why it is so important to understand logical fallacies and take them seriously when they are pointed out to you: they result in arguments with invalid logical structures. In other words, they create arguments in which the truth of the premises does not guarantee the truth of the conclusion.

To further illustrate this, let’s move on from affirming the consequent fallacies and talk about a different fallacy: post hoc ergo propter hoc (or just “post hoc” for short). This is one of the most common fallacies that I encounter in debates about scientific topics, and it takes the following logical structure.

  • Premise 1: Q happened before U
  • Conclusion: Therefore, Q caused U

The problem with that should be pretty obvious: the fact that one thing happened before another doesn’t mean that one caused the other. In other words, the conclusion does not follow necessarily from the premise. We can easily illustrate this with simple examples.

  • Premise 1: I performed a sacrifice, then it rained
  • Conclusion: Therefore, my sacrifice caused the rain


  • Premise 1: I read a book, then had a heart attack
  • Conclusion: Therefore, reading the book caused the heart attack

Do you see how that works (or, rather, doesn’t work)? The fact that one thing happened before another does not lead to the conclusion that there is a causal relationship. The logical structure is invalid, and any arguments containing this structure (i.e. containing a post hoc fallacy) must be rejected. On a side note, this is a fundamental reason why anecdotes are worthless as evidence of causation. The fact the you got better after taking something doesn’t mean that it worked, and the fact that you had an adverse event after taking something doesn’t mean that the treatment caused the event. Both of those arguments contain this structure (i.e., they are post hoc fallacies), and, as such, they are not valid, and the conclusion does not follow necessarily from the premise.

There are lots of other examples of this overarching type of fallacy, such as denying the antecedent, correlation fallacies, guilt by association, arguments from ignorance, etc., but they all have the same problem. Namely, they are invalid because they set up a logical structure in which the conclusion does not follow necessarily from the premises.

The fallacies of untrue premises

Another major “group” of fallacies work by either implicitly or explicitly making an untrue premise. The problem here should be obvious: if an argument relies on an untrue claim, then the argument must be rejected (i.e., it is not sound). As before, an easy way to test for this problem is to see if you can find any examples in which the argument doesn’t work.

Note: these groupings of fallacies are not officially recognized. They are just groupings that I personally find to be useful when thinking about fallacies and how/why they work (or don’t work, as the case may be).

Let me explain what I mean by using one of the most common variants of these fallacies: the appeal to nature fallacy. This fallacy occurs whenever someone asserts that something is good/useful/healthy because it is natural or that something is bad/useless/unhealthy because it is unnatural. When can set this argument up the following way.

  • Premise 1: X is natural
  • Conclusion: Therefore, X is good

That obviously doesn’t work, however, because there are plenty of true things that we can substitute for premise 1 that clearly result in false conclusions. For example:

  • Premise 1: The plague is natural
  • Conclusions: Therefore, the plague is good

Now, you could stop right there, and call this another variant of the non-sequitur fallacy, and you wouldn’t be wrong. This structure, as I have presented it, clearly is invalid because the conclusion does not follow from the premise. However, I think that there is a more useful way to think about this fallacy and others like it. Namely, this fallacy has an assumed premise that is false. It assumes that everything natural is good. Thus, there is really an implicit second premise.

  • Premise 1: X is natural
  • Premise 2: Everything natural is good
  • Conclusion: Therefore, X is good

That second premise is, however, clearly false, and as a result, the argument fails (i.e., it’s not sound). Importantly, that premise (or some variant thereof, including the inverse “everything unnatural is bad”) is present in all appeal to nature fallacies. Thus, anytime that this fallacy is present, the argument must be rejected, because it inherently assumes an untrue premise.

no matter what crackpot notion you believeThere are many other, “appeal to” fallacies, and they all have the same basic structure and problem. For example, appeal to authority fallacies occur when you say that something is true because of the person who says that it is true. When you do that, however, you are inherently invoking the premise that the person in question is infallible, which is clearly false. Other examples include appeals to popularity (which assume that everything popular is good/right), appeals to antiquity (which assume that anything old is good/right), appeals to tradition (which assume that anything traditional is good/right), etc. (note: the one exception to this structure is the appeal to emotion fallacy, which simply makes an argument based on emotions, rather than facts or logic).

Note: You could also apply my “implicit untrue premise” explanation to some of the non-sequitur fallacies that I described earlier. For example, you could say that post hoc ergo propter hoc fallacies include the assumed premise that if Q happens before U, then Q caused U. There is nothing wrong with that way of conceptualizing those fallacies, and you are welcome to use it, I just personally find that explanation to be more complicated when the premise isn’t as simple as “everything natural is good.” You can, however, think of these fallacies either way. You can think of them as having an implicit and untrue premise or as having an invalid structure. I don’t care which you use, just so that you understand the concepts.

Another common fallacy is much less subtle and directly states untrue premises. I am, of course, referring to the straw man fallacy. This occurs whenever you attack a weakened or misrepresented version of your opponent’s argument, then claim to have defeated their actual view.  In other words, you say, “My opponent believes X, and X is wrong for reasons Y” when, in reality, X is a distortion or misrepresentation of what your opponent believes. Thus, your first premise is false (there are also subsets of this fallacy such as reductio ad absurdum).

Fallacies of the false dilemma are yet another example of fallacies that operate via untrue premises. These take the form of “Either X or Y is true, X is false, therefore Y is true.” This sounds great, until you realize that premise one is false, and there was actually a third option (Z) that wasn’t stated.

Detecting logical fallacies

Finally, I want to briefly talk about some tools for detecting whether a logical fallacy has been committed. Obviously, your best bet is to study the different types of fallacies and learn how each of them works. I have compiled a list of common fallacies to help with that, as have many other sites (e.g. Internet Encyclopedia of Philosophy [this is probably the most comprehensive one], Skeptical Raptor, Your Logical Fallacy Is, and many others) . Let’s assume, however, that you don’t have time for that, you can’t be bothered, or maybe you have studied them, but still struggle with particular arguments (don’t worry, that happens to all of us). Fortunately, there are some simple things that you can do.

First, I strongly recommend that you practice breaking an argument down into a syllogism like I have done throughout this post (start with the actual facts in the argument). Often, when you do that the problems will jump right out at you. If nothing immediately jumps out at you however, then try replacing the facts with letters (again, like I have done throughout). Then, look carefully at that structure and see if it is valid. See if the conclusion has to follow from those premises, and see if there are any implicit premises that need to be added. If, at that point, it is clear that either the conclusion does not follow necessarily from the premises or that there is an implicit and untrue premise, then you are done. The argument is flawed and you should reject it. If neither of those are obvious, then move onto the next tool.

The second tool is simply to try to find examples where the logical structure of the argument fails. Use the syllogism that you constructed before, but this time, make actual premises that are true but unrelated to the topic of debate (like I did by using a sacrifice to show that post hoc fallacies were invalid). If you can find any examples (hypothetical or actual) where the premises are true, but the conclusion is clearly false, then you have just demonstrated that the logical structure is invalid (assuming that you were careful and did not alter the structure, otherwise you’ve committed a straw man fallacy). This is a very useful tactic that you should get in the habit of using (I explained it in more detail here).

Although those two tools are useful, unfortunately, they aren’t all-encompassing. There are many other types of fallacies that I have not covered here because they are more specialized and difficult to generalize. Many of these are actually errors in debate tactics more than errors in reasoning. For example, a red herring fallacy occurs when, in a debate, you ignore your opponent’s argument/question and go off on an irrelevant side tangent in order to dodge a problem that they pointed out (politicians are masters of this). This type of fallacy is much harder to detect via a simple key like what I have presented, because there is no way to really construct a syllogism. It’s not a proper argument. Rather, it is a means of avoiding an argument. Similarly, for both straw man fallacies and false dilemma fallacies, you need to have enough knowledge on the topic at hand to tell that a false premise has been presented. That is the only way to detect them. So, although the tools that I have presented are useful and work in many situations, there really is no substitute for actually studying fallacies and becoming familiar with them.


Obviously, this post has been far from exhaustive, and there are many other fallacies (and even types of fallacies) that I didn’t address. However, this should give you a basic understanding of why fallacies are a problem, as well as some tools for detecting them. Anytime that a fallacy is present, the argument must be rejected, because you cannot be confident that the conclusion is actually supported by that argument. Thus, you should be mindful of logical fallacies and strive to avoid them in your arguments and views. Further, if someone points out that you have committed a fallacy, take that accusation seriously and look closely at their claim to see if it is correct. No one is immune to these flaws in reasoning, but there is no excuse for ignoring them once they have been pointed out to you.

 Note: It is worth emphasizing that when an argument contains a logical fallacy you must reject the argument not the conclusion (rejecting the conclusion rather than the argument is actually a fallacy known as the fallacy fallacy [that’s not a typo]). It is entirely possible to have an invalid argument, but a true conclusion. In other words, your conclusion may be true, but you cannot use that particular argument to support it, and it must be supported by other lines of evidence/reasoning.

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Vaccine injuries and confirmation biases

Humans are remarkably bad at accurately discerning patterns. All of us (skeptics included) are prone to confirmation biases and logical flaws in reasoning. We don’t like to be wrong, and, as a result, we tend to cling to things that appear to support our preconceived notions, while blindly ignoring things that discredit our views. Even worse, we tend to seek out others who share our views, and we enter echo chambers where we only hear from people who agree with us. This can happen for any of our views, whether they are views on science, politics, religion, etc. and it sets up a dangerous cycle, wherein we first settle on a position, then only accept information that agrees with that position, while simultaneously allowing that information to reinforce our original position. It’s a circle of ignorance that constantly bolsters our view, even if that view is totally incorrect. Again, this can happen to anyone on any topic, but in this post, I want to briefly use anti-vaccers and “vaccine injuries” as an instructive example in how this plays out.

Image via Things Anti-vaccers Say. Also, note that this whole line of reasoning is absurd. DNA doesn’t work the way that they are proposing.

If you ask people who oppose vaccines why they do so, you will likely receive a litany of “vaccine injuries” that they have personally seen or heard reported by others. Some of the more well-known of these include things like autism and SIDs, but the list generally doesn’t stop there. Depending on which anti-vaccer you ask, you may also hear that vaccines cause asthma, allergies, depression, violence, lupus, fibromyalgia, behavioral ticks, shaken baby syndrome, and just about every other issue that you can think off. Indeed, anti-vaccers seem content to view almost everything as a vaccine injury (even homosexuality [again, depending on who you ask]). The Facebook page Things Anti-vaccers Say does a good job of documenting these assertions, and I will include several of their screenshots throughout this post as both examples and discussion points.

It’s important to pause here to note several things. First, to be clear, vaccines do have side effects (as do all real medical interventions), but those side effects are either extremely mild or extremely rare, and the known benefits far outweigh the risks. Further, most of the things that anti-vaccers blame vaccines for simply are not caused by vaccines. For example, the association between vaccines and autism has been well-studied, and those studies have consistently found that vaccines do not cause autism (details and sources here). Similarly, not only do vaccines not cause SIDs, but they may actually reduce the rate of SIDs (details and sources here [see #64]). This raises the obvious question of why anti-vaccers see vaccine injuries everywhere that they look?

See this post for sources and more details.

Part of the answer is simply a reliance on shoddy sources. Anti-vaccers frequently get their information from notoriously counterfactual websites like Natural News, Green Med Info, Info Wars, and a host of others. Further, they readily accept anecdotes as evidence, which is where the topic of “vaccine injuries” really comes into play. What I see happening over and over again is that one parent tells a tale of how their child received a vaccine then developed autism, started coughing, died from SIDs or shaken baby syndrome, etc., and everyone in the anti-vaccine community makes an astronomical and logically invalid leap to the conclusion that the vaccine was responsible. In reality, however, anecdotes cannot establish causation, and the fact that one event followed another does not mean that the first event caused the second one. Indeed, that line of reasoning is a logical fallacy known as post hoc ergo propter hoc. Things do sometimes just happen to occur together. For example, in a previous post, I looked that the rate of autism and the rate of vaccination and showed that, mathematically, we would expect there to be thousands of cases each year where the first signs of autism were noticed shortly after a vaccination just by chance! This is a major reason why anecdotes aren’t valid evidence: coincidences do happen. Further, using anecdotes for things like vaccines and autism is particularly absurd because of the overwhelming scientific evidence that vaccines do not cause autism. You don’t get to reject a scientific study based on an anecdote. That isn’t how science works.

Note: Many anti-vaccers also site things like VAERS, package inserts, and the VICP, but those are also unacceptable sources for establishing causation as I explained here.

The explanation that I have just offered seems good at first, but it really just raises more questions than it answers. Most importantly, why are anti-vaccers willing to accept shoddy evidence? This is where confirmation biases come in, and I’d like to use the screenshot to the right as an example. When most people hear a report like this of a “healthy 100-year-old woman dying in six months” (paraphrasing) the cause of death seems pretty obvious: she was 100 years old! It is well established that the very elderly have weakened immune systems and  a reduced ability to recover from illnesses and injuries, and even someone who is in good health (for a 100-year-old) can succumb very quickly to even a minor aliment. Nevertheless, as you can see in the comments, to some anti-vaccers, this had to be a vaccine injury! She received a vaccine (or so they assume) then died a few months later, so the vaccine had to be the cause! (See what I mean about anecdotes being worthless as evidence of causation?)

I can, of course, give lots of other examples of this, and some are even worse. For example, when faced with evidence that homeopathic teething tablets were potentially causing sickness and even deaths in young children, the anti-vaccer on the left chose to blame vaccines instead. Think about how incredible this is. Here, you have the FDA saying that they have evidence showing that this product is likely dangerous, but instead of listening to the FDA, this anti-vaccer shifted the blame to vaccines despite a complete and total lack of evidence to support that claim! They were so convinced of the evil of vaccines that they were willing to blindly overlook an actual danger and place the blame on vaccines instead.

So, what is going on here? This answer is confirmation biases and, more generally, motivated reasoning. Anti-vaccers believe strongly that vaccines are dangerous, and that belief causes them to see vaccine injuries everywhere. That’s what confirmation biases do: they make you latch onto anything that seems to support your position, even if the evidence is shoddy. Thus, when most of us hear about something like a 100-year-old woman who “suddenly died,” we realize that there are lots of potential causes that are far more plausible than a vaccine, but if you are a committed anti-vaccer, you don’t see those other causes, because they don’t fit your mental narrative. All that you see is the vaccine. Similarly, for the homeopathic anti-vaccer, accepting that a homeopathic product was dangerous didn’t fit their mental narrative, but thinking that vaccines were at fault did fit their mental narrative. So, despite the evidence suggesting that the homeopathic product was dangerous and despite the total lack of evidence to suggest that vaccines were the cause, they blamed the vaccines. That is how powerful confirmation biases and motivated reasoning can be. They can make you think that something dangerous is actually safe and that something safe is actually dangerous.

confirmation biases

Although this image is targeted specifically at anti-vaccers, this circle of ignorance can occur for anyone on any topic. Even if your conclusion is correct, it may bias you and cause you to both accept shoddy sources and use those sources to bolster your position.

Now that we have gone over a few examples, let’s turn to what I think is the most dangerous aspect of confirmation biases: their ability to reinforce a belief. Every time that an anti-vaccer sees a non-existent vaccine injury, it reinforces their belief that vaccines are dangerous, which is obviously a big problem. This goes back to the circle of ignorance that I mentioned earlier. For one reason or another, anti-vaccers decided that vaccines are dangerous. Because of that belief, they see “vaccine injuries” that aren’t really there, and those “vaccine injuries” then make them even more convinced that vaccines are dangerous. It is a never-ending circle that sinks them deeper and deeper into ignorance and conspiracy theories. Further, this situation is made even worse by online groups where anti-vaccers can see the anecdotes of other anti-vaccers. Here again, their confirmation biases cause them to blindly accept these stories as evidence against vaccines, even though it is illogical to do so.

At this point, you may be ready to laugh at anti-vaccers for being stupid, but you shouldn’t be. As I have previously argued, most people who reject science aren’t stupid or crazy, they are just misinformed and have succumbed to their confirmation biases and motivated reasoning. Importantly, this is not a problem that is limited to science-deniers. It is a problem that affects everyone. All of us are prone to confirmation biases, and we all should constantly check our views to make sure that we are following facts and logic rather than following what we want to be true. We need to carefully consider evidence rather than blindly latching onto the things that fit our mental narratives. Perhaps most importantly, we should always consider the possibility that we are wrong. Being willing to be wrong is (in my opinion) the only way to break the circle of ignorance. Unless you are actually willing to be wrong, you will never be able to accept evidence that is contrary to your beliefs, and it is important that you are capable of doing that. To quote an excellent Dr. Who episode, “the circle must be broken.”

Note: Please do not use the VAERS, package inserts, or VICP as evidence unless you have read this post.

Note: You may be wondering how a homeopathic tablet could be dangerous since they are usually just water, so here is the story in a nutshell. This product is supposed to contain very tiny amounts of belladonna, a substance which is quite harmful in higher doses (as is true of many active ingredients in homeopathy). However, the dose makes the poison, so when diluted to extremely low levels (as homeopathic products generally are) this product is harmless (it’s also useless, but that’s beside the point). However, the FDA kept receiving numerous reports of children becoming sick or even dying after taking the tablets, and the symptoms matched the known symptoms of belladonna poisoning. So, the FDA started investigating, and they found that the amount of belladonna in the tablets was inconsistent, which is a huge problem because, as I said, this chemical is toxic at higher doses. So, it is extremely important that it only be present in very low doses. Thus, although this does not conclusive demonstrate that the homeopathic tablets were at fault, the combination of inconsistent doses of a potentially toxic chemical and the fact that children who took it where experiencing the symptoms of receiving a high dose of that chemical certainly makes a good case against the homeopathic product. Again, a more proper study is necessary for a conclusive answer, but the evidence is certainly strong enough that parents should take it seriously, and blindly rejecting that evidence in favor of arbitrarily blaming vaccines is insane. Finally, please note that this is a very different situation from the anecdotes that parents use against vaccines, because those anecdotes are all over the map, don’t match the symptoms of vaccine ingredients at the doses at which they are present, and frequently fly in the face of actual studies. In most cases, there is no plausible mechanism through which the vaccine could be at fault.

Posted in Rules of Logic, Vaccines/Alternative Medicine | Tagged , , , , , , , | 4 Comments

Genetics provide powerful evidence of evolution

Many people are under the false impression that evolution is just a guess or a belief, when in reality, it is one of the most well-supported concepts in all of science. The evidence for it is overwhelming and comes from many different disciplines such as paleontology, comparative anatomy, biogeography, and perhaps most significantly, genetics. Indeed, modern genetic tools have allowed us to repeatedly test evolution’s predictions, and those predictions have consistently come true. Therefore, I am going to explain in simple terms what the genetic evidence is and why it is so compelling. As I will show, the evidence perfectly matches the predictions that the theory of evolution made decades before we could test those predictions. Further, the patterns do not make sense if our modern organisms were specially created, because there is no reason why a creator would have had to make life with these patterns. In other words, if you want to say that God created our modern organisms, then you are left in the awkward position of arguing that out of an infinite range of possibilities available to him, God chose to create life in the one and only way that would be consistent with the predictions of evolution.

Note: Throughout this post I will use the term “creationist” to refer to people who deny evolution. There are many sub-categories within that, and there are also Christians who accept both evolution and the Bible (theistic evolutionists). I am not attacking Christianity or religion here. Rather, I am simply explaining why the evidence overwhelmingly supports evolution and refutes creationism.

 Note: I am going to talk about relationships based on genetic similarities and shared genetic traits throughout this post, but please realize that I am doing this for simplicity. Actual phylogenetic studies employ rigorous statistical analyses to look not just at the proportion of shared DNA, but also at parsimony and various other factors. So I am being simplistic to avoid losing anyone, but the actual science is more complex, and the more that you understand it, the clearer it becomes that evolution is correct.


That basics that everyone agrees on

To start this post, I need to explain the most basic concepts of how we use genetics to assign evolutionary relationships, and the easiest way to do that is with human families. Imagine that you gave me blood samples from yourself and five relatives, all of whom were in your generation. I then extracted and sequenced the DNA from those samples, and I found that there was one person whose genetic code was very similar to yours but more different from the other four samples. Thus, you two share a substantial portion of the variable regions of your DNA. From that, I would conclude that you two share a more recent common ancestor with each other than with your other relatives. In this case, that ancestor would probably be your parents (i.e., you’re probably siblings). This should make good sense. You obviously got your DNA from your parents, as did your sibling. Thus, since you both got your DNA from the same source, we naturally expect your genetic code to be more similar to your sibling’s than to the codes of people who have different parents.

As I look at the data further, I also find another pair of two individuals who are more similar to each other than they are to either you or your sibling, thus suggesting that they share a recent common ancestor that you do not have. However, both of them are more similar to you and your sibling than they are to the final two relatives. This would suggest that you and they share a recent common ancestor that is not shared by the final two relatives (e.g., you’re cousins who share grandparents). Finally, the last two individuals are again closely related to each other, but they are more distant to the rest of you. This would suggest that the six of you have a more distant common ancestor (perhaps you share a great grandparent).

This is an example of a cladogram (aka phylogenetic tree) showing the relationships between you and your five relatives in my example.

This is an example of a cladogram (aka phylogenetic tree) showing the relationships between you and your five relatives in my example.

As you can see, we can use those genetic data to reconstruct your family tree (what we like to call your phylogeny in science), and we can illustrate it using a phylogenetic tree or cladogram like the one on the right. On these diagrams, vertical lines represent common ancestors. Thus, you can see that you and your sibling share a recent ancestor (your parents), and you, your sibling, and your cousins share an ancestor slightly further back (your grandparents), and all six of you share an ancestor even further back (your great grandparents). Again, this should all make good sense when you think about how DNA is passed. All six of you share a certain amount of DNA because you all inherited it from your great grandparents. After that, however, things began to diverge. One of your great grandparents’ children went on to become your grandparent, while another one went on to produce your more distant relatives. Thus, you, your sibling, and your cousins are more alike because you all received DNA from the same source (your grandparent). Then, one of your grandparents’ children went on to become your parents, while another became your aunt/uncle and produced your cousins. Does that make sense?

I want to pause here for a moment to make a crucially important point. In my example, we did not need actual DNA from your ancestors. Rather, we were able to infer their existence from the patterns that we saw in the DNA from the current generation. This is a very important strength of genetic analyses: we can use data from the current generation to infer the existence of past ancestors.


Broadening the scope

Everything that I have said thus far is universally accepted. No one disagrees that these genetic tools can determine family relationships like this, and even the most die-hard creationist would have no problem with what I have said. However, the power of these tools doesn’t stop there. We can also use them for an entire species. For example, we can trace the ancestry of all humans back to a common source. Here again, creationists have no problems. They agree that these methods are reliably showing true relationships, and it’s not simply a case of some people happening to have similar DNA. They agree that the similarities are similar by descent and indicate common ancestry (i.e., they accept that these methods can reliably identify ancestors that we do not have DNA samples from). In other words, they agree that these are actually showing real, evolutionary relationships within people (they would argue that the tree goes back to Noah and his family as the common ancestor).

We can, however, go even further than just a species, we can also use it for complex species with many breeds (such as dogs) or even for entire families of animals (in the scientific classification of organisms, family is the third most specific classification, followed by genus and species). We can, for example, show that all species of ducks (family Anatidae) descended from a common ancestor. We can also show that all tree frogs (family Hylidae) share a common ancestor, all pthyons (family Pythonidae) share a common ancestor, all kangaroos (family Macropodidae) share a common ancestor, etc. Again, creationists are OK with this. At the family level, they agree that these methods are showing true relationships. You see, young-earth creationists argue that on Noah’s ark, Noah did not take two of each species, but rather took two of each “kind,” which they arbitrarily define as being roughly equivalent to scientists’ term “family.” Thus, they agree with these data, because they think that all modern ducks descended from a single pair of ducks on the ark, all modern tree frogs descended form a pair of tree frogs on the ark, etc. I have even seen some of them go as far as saying that the genetic evidence within families is evidence of creationism/Noah’s Ark (that is a logical fallacy known as affirming the consequent).

Cladogram of dog breeds. Figure 1a from vonHoldt et al. 2010.

Cladogram of dog breeds. Figure 1a from vonHoldt et al. 2010.

Creationist’s disagree, however, the instant that we start extending beyond the family level. Take marsupials (pouched mammals) for example. Using these genetic techniques, we can tell that many carnivorous marsupials, like Tasmanian devils and quolls are all in a single family (Dasyuridae) and share a common ancestor. Creationists are fine with that, and agree that the methods are showing true relationships. However, we can use exactly the same methods to broaden the scope just a little bit further and show members of Dasyuridae are more closely related to the Myrmecobiidae family than they are to any other living marsupials. Thus, we can tell that Dasyuridae and Myrmecobiidae evolved from a common ancestor, and we group them together into the order Dasyuromorphia (order is one step broader than family). At that point, creationists suddenly disagree. Suddenly they insist that these methods are just showing similarities, not true relationships. They are even more upset when we use exactly the same techniques to show that the order Dasyuromorphia evolved from the same common ancestors as the orders Notoryctemorphia and Peramelemorphia (Gallus et al. 2015). Further, we can keep going with thus until eventually we have a cladogram for all marsupials that shows that all of them share a common ancestor and are more related to each other than they are to other mammals (just like you are more related to your sibling than to your cousins; Cardillo et al. 2004).

A phylogenetic tree of several marsupial families. Figure 7 from Cardillo et al. 2004.

A phylogenetic tree of several marsupial families. Figure 7 from Cardillo et al. 2004.

We don’t have to stop there, however. We can continue to use the same methods to show that all mammals share a common ancestor, all animals share a common ancestor, and ultimately that all life on planet earth evolved from a common ancestor. Creationists, of course, object to this in the strongest possible terms. They insist that these genetic similarities aren’t actually showing real relationships, and they are adamant that the fact that two groups share more DNA with each other than with some other group doesn’t indicate that those two groups evolved from a common ancestor. As you can hopefully now see, however, that argument is logically inconsistent because it is completely and totally arbitrary to say that these methods work within families, but don’t work for taxonomic levels higher than that. That reasoning is logically invalid and completely ignores the evidence. Look at the cladogram above, for example. It shows some of the relationships that I described in marsupials, and I have colored the parts that creationists agree with green and the parts that the disagree with red. As you can see, within each family, they accept quite a few common ancestors. They agree that these methods can reliably show ancestry, yet as soon as we move beyond the family level, they say that the methods don’t actually show common ancestry. They agree, for example, that all members of the genera Dasyurus, Neophascogale, and Phascolosorex descended from a common ancestor, yet that disagree that the families Dasyuridae and Myrmecobiidae descended from a common ancestor. That belief is completely arbitrary and has no scientific basis or logical credibility. To put this another way, look at the clodagram that I showed early for dog breeds (which creaitonists have no problems with), then look at the cladogram below for all life on planet earth, and tell me what the difference is. Explain to me why we should accept that these methods work for dogs but arbitrarily believe that they don’t work for higher taxonomic levels.

Phylogenetic tree of life on planet earth. Via the University of Texas.

Phylogenetic tree of life on planet earth. Via the University of Texas.










Extraordinary predictions

I want to take a minute here to try to impress on you just how extraordinary these genetic results are. Scientific theories are often judged by their predictive power. In other words, good theories are ones that can accurately predict the results of future experiments, and the more extreme the predictions, the better. In this case, the theory of evolution made the astounding prediction that we should see these genetic patterns decades before we actually had the ability to test them.

When Darwin first proposed the theory of evolution, genetics were unknown. No one knew what DNA was or how traits where inherited (see note). In fact, Darwin himself was totally wrong about how inheritance worked (he subscribed to the “blending” hypothesis wherein the traits of two parents blended together). Nevertheless, despite being wrong about the mechanism, it was clear that there had to be some way that the information for traits was passed from parents to offspring, and if evolution was true, then scientists realized that the information should record evolutionary history. In other words, if evolution was true, it should be possible to use that information in exactly the way that I described to show that all life traces back to a single common ancestor.

That was already an extreme prediction, but it didn’t stop there. You see, it wasn’t enough for there to be a pattern. Rather, the pattern had to match overarching morphological patterns. In other words, it had to show that all of the parrot families share a common ancestor, all frogs share a common ancestor, all marsupials share a common ancestor, etc., and that is exactly what we find. Further, this pattern had to match the fossil record, which is where things get even more extraordinary. You see, it may make intuitive sense to you to expect that all frogs would be genetically similar, even if they were specially created (more on that later), but why would genetics show that modern amphibians and modern reptiles share a common ancestor? That’s not something that you would expect under creationism, but it is what evolution predicted, because the fossil record clearly showed that both modern amphibians and reptiles evolved from ancient amphibians. Thus, evolution predicted that modern amphibians and reptiles should share a common ancestor. Similarly, the fossil record showed that amphibians evolved from fish, and that both reptiles and birds evolved from amphibians. Therefore, if those fossilized patterns are correct, we should see the same patterns in DNA, and we do! Think about how amazing that is. Evolution predicted the existence of an extremely precise pattern long before we could test that prediction. If evolution isn’t actually true, then you have to say that the patterns that we see in morphology, the fossil record, and genetics just happen to perfectly match up. That’s insane! Further, let’s be clear that I am only naming a handful of the predictions here. They also extend to all plants, bacteria, archaea, invertebrates, and other chordates. We are talking about thousands of predictions that evolution nailed! That is extremely strong evidence that evolution is correct. To put that another way, what are the odds that evolution would have gotten all of those predictions right if evolution wasn’t actually true?

Crocodiles are more closely related to birds than other reptiles. Image via Green et al. 2014.

Crocodiles are more closely related to birds than other reptiles. Image via Green et al. 2014.

To really drive this home, let’s talk more about birds for a minute, because their story is incredible. As I explained in a previous post, there is a ton of fossil evidence showing that birds evolved from dinosaurs. We have lots of transitional fossils showing that this occurred. Further, the fossil record shows the existence of a large phylogenetic group known as archosaurs, which included both ancient crocodilians and the group of dinosaurs that evolved into birds (more details at the University of California). This tells us that crocodiles and birds should actually be each other’s closest living relatives, and it leads to an absolutely incredible prediction. Genetically, not only should birds fall out as reptiles, but crocodiles should actually be more closely related to birds than they are to other reptiles. That is an amazing prediction that makes no sense under creationism. Why would God give crocodiles a genetic code that shares more in common with birds than other reptiles? As you might have guessed, however, this prediction totally came true! Genetically, birds are actually reptiles, and crocodiles share more DNA with birds than with other reptiles (Green et al. 2014)! Again, this is because birds and crocs share a common ancestor (just as you and your sibling are genetically similar because of a common ancestor). If you stop and think about this for a second, it is mind-blowing. Genetically, crocodiles are more similar to birds than they are to other reptiles. If that doesn’t make you question everything, then I don’t know what will.

Note: Technically, Gregor Mendel (who discovered how genetic inheritance works) was Darwin’s contemporary, but Mendel’s work was largely unknown until well after his death.


Functionally arbitrary similarities

At this point, you might be tempted to think that these genetic patterns are there by necessity. For example, you might think that all frogs have similar genetic codes simply because they all have to have similar codes in order to have the characteristics of a frog. Thus, you might think that these genetic patterns are functionally necessary and would have to exist even if modern organisms were specially created. There are, however, numerous problems with that line of reasoning.

First, that argument would only have the potential to apply to the patterns within fairly narrow taxonomic units, and it would not explain the overarching patterns. In other words, the fossil record tells us that modern amphibians evolved from ancient fish, modern reptiles evolved from ancient amphibians, modern mammals evolved from ancient reptiles, birds and crocodiles both evolved from an ancient archosaur (reptile), etc. As I have already explained, genetics show us exactly the same progression, and there is no reason why that pattern had to exist. An all-powerful being could easily have created birds, reptiles, amphibians, mammals, etc. without making this pattern. Indeed, he could have created life such that each “kind” was unique and did not show any patterns of relatedness to the other “kinds.” To put this another way, why did God make crocodiles more similar to birds than to turtles?

Second, even within more narrow taxonomic groups (defined by morphology in this case), there is still actually no need for the level of genetic similarities that we observe. As I will explain, the genetic code is remarkably redundant and pliable, and you can have two very similar organisms with very different genetic codes and evolutionary histories (conversely, you can also have two very different organisms with comparatively similar genetic codes, think about crocodiles and birds again). I will explain more details about how that works in a moment, but let me give you the big picture first. There is a process known as “convergent evolution” wherein similar habitats and life histories cause two distantly related species to evolve to have similar morphological or physiological traits, but because they evolved independently, their genetics are quite different.

A sugar glider (left) and flying squirrel (right). Despite appearing similar, they are actually very distantly related, and each species evolved to be similar via convergent evolution.

A sugar glider (left) and flying squirrel (right). Despite appearing similar, they are actually very distantly related, and each species evolved to be similar via convergent evolution.

Sugar gliders (Petaurus breviceps) and northern flying squirrels (Glaucomys sabrinus) provide a really nice example of convergent evolution. As you can see in the image, they look extremely similar, and they both possess remarkable adaptations such as a large flap of skin that they can use to glide, a large bushy tail to steer with, large forward-set eyes for good night vision, etc. If you didn’t know any better, you would probably think that they are close relatives, but you’d be very wrong. You see, sugar gliders are marsupials, whereas flying squirrels are placental mammals. So genetically, flying squirrels are far closer to you and me than to a sugar glider, and sugar gliders are far more related to kangaroos than to flying squirrels. Nevertheless, despite having very different genetic codes, they have very similar morphology (with regards to the adaptations for gliding) because they both adapted to similar habitats/life styles. There are tons of other examples like this that I could give, but hopefully you see my point: there are often multiple ways to achieve the same basic outcome, and you don’t need to have similar genetics to be morphologically similar.

Note: Lest anyone try to say that this example actually discredits evolution because it shows that morphology and genetics don’t always match up, there are other traits that distinguished them long before genetics (e.g., the pouch), so this was not a case of morphology and genetics disagreeing. Nevertheless, my point stands that both species evolved many of the same traits in different ways, and different genetic codes can achieve the same outcome.

 So why is it that the genetic code is so malleable? Why can organisms with different genes evolve the same basic structures? To answer that, you need to understand how DNA works. It consists of four base pairs (represented as A, T, C, and G), and those bases are arranged in groups of three, with each group coding for an amino acid. The arrangement of those amino acids then determines what proteins are formed. Thus, a string of DNA codes for a series of amino acids which in turn forms a protein. That code is, however, highly redundant, and several different groups of bases can form the same amino acid (and therefore same protein). For example, the amino acid proline can be formed by the codes CCT, CCC, CCA, or CCG. They all form the same amino acid, and therefore, the same subsequent proteins. Indeed, most amino acids can be formed by at least two different sets of bases. Therefore, because proteins are formed from strings of numerous amino acids, you can have tons of organism all producing the same protein, but doing so via different genetic codes (there is also redundancy in the proteins themselves in that you can swap some amino acids and still get the same basic protein, this does have an effect on the function of the protein, but not a significant enough one to really make creationists’ argument persuasive).

Additionally, large portions of the genomes of most organisms are what are referred to as “junk DNA” (Rands et al. 2014ENCODE Project Consortium). Exactly what these are and what they do is still the subject of much debate, but it does appear that they are not actively coding nearly as much as regular DNA (if at all), and mutations in those regions are unlikely to have large impacts on organisms. Indeed, when you combine the presence of junk DNA and the redundancy in the genetic code, it turns out that for many species, most mutations are actually “neutral” and have no effect on the organism (Eyre-Walker et al. 2007).

The consequence of all of this is really important. It means that there can be a lot of variation in genetic codes without it affecting functional traits (or in some cases, with it only have minor affects). In other words, an omnipotent, all powerful being could easily have designed two organisms that were nearly identical in morphology and physiology, but had extremely different genetic codes. To put that another way, as it turns out, it is not at all necessary for two species that look and behave like frogs to have similar DNA. To be clear, there certainly are conserved sections of DNA, and some sections of the genetic code are similar for functional reasons, but there is no reason why the similarities should consistently extend across the entire genome. Because of the redundancies in the genetic code, you could easily have two “frogs” with radically different genetics. Indeed, it would be entirely possible for an all-powerful all-knowing God to make four identical “frogs” one of which had protein sequences that matched those of birds, one of which had protein sequences that matched those of fish, one of which had protein sequences that matched those of reptiles, and one of which had protein sequences that matched those of mammals! Lest you think that I am pulling your leg, think about birds and crocodiles again.


“God did it”
I want to conclude this post by talking about the most common response that I get to all of this. More often than not, when I present this evidence to a creationist, I get the following reply, “well, those patterns are just the way that God created everything, and the common patterns exist because of a common creator, not because of a common ancestor.” There are, however, numerous problems with this response, so let me lay them out for you.

First, as I explained at length earlier, this response is logically inconsistent. If you agree that genetics show true relationships at the family level (as all creationists seem to), then you cannot arbitrarily say that they don’t work at higher levels. That is not valid reasoning.

Second, this response is what is known as an ad hoc fallacy. It is a logically invalid cop-out that is not falsifiable (thereby violating a key requirement for science) and would never be accepted by anyone who wasn’t already convinced that creationism is true. You might as well propose that Barney the dinosaur is actually a real magical dinosaur who created these patterns just to screw with us. Just like the “God did it” response, I technically can’t disprove that claim, but it is clearly not a rational argument.

Third, this response has serious logical problems because of the nature of the genetic code. There are several parts to this, but first I want to address the one that I haven’t talked about yet, and it is easiest to do that by way of example. Like most modern scientists, I have been forced to learn some computer coding, which I use to write codes for organizing and sorting data, running statistical models, simulating data, and even making fictional examples for this blog. I am, however, a pretty horrible programmer. My codes always work in the end, but they tend to be clunky, inelegant, and redundant. Further, frequently when I need to code something, I simply take an existing code and modify it. That saves me time, but it generally produces codes with irrelevant lines that are left-overs from the codes’ original functions, as well as unnecessarily complicated processes that would have been far simpler if I had started from scratch. In contrast, someone who knew what they were doing and built each code from scratch, would be able to make codes that do exactly what mine do, but theirs would be very elegant and free of redundancies and irrelevant lines of code.

It may seem like I am off topic here, but computer codes are actually remarkably analogous to genetic codes. Zeros and ones tell computers what to do in much the same way that As, Ts, Cs, and Gs tell organisms what to do. Now, ask yourself this question, if all life was created by an omnipotent, omniscient God, would you expect elegant, well-written codes that were free of redundancies, or would you expect clunky, bulky codes, that were hodgepodged together from existing codes and are full of redundancies and lines that no longer do anything? I would certainly expect the former, but what we find is the latter. The more that we examine organisms’ genetic codes, the clearer it becomes that they were made by randomly modifying existing codes, rather than writing new codes from scratch. That is why we end up with large non-functional (or barely function) regions and codes that carry over from one group to the next. To put it simply, if God specially created modern organisms, then he is a terrible programmer.

This brings me to my final point, which is probably the most important one. As I have tried to make clear throughout this post, the genetic patterns that we see among organism are exactly what evolution predicted at every level. The relationships and patterns within groups are exactly what evolution predicted, and the overarching patterns of relationships among groups are exactly what evolution predicted. We are talking about thousands of predictions that evolution consistently got right. Further, as explained earlier, these patterns don’t have to exist for us to have organisms that look and function like our modern organisms. An all-powerful, all-knowing being could easily have created modern organisms such that there was no pattern at all. He could have scrambled protein sequences such that, for example, some bird proteins matched frogs, others matched fish, others matched reptiles, others matched trees, etc. Alternatively, he could have made extremely inconsistent patterns. He could have made some birds appear to be related to reptiles, others to fish, others to amphibians, etc. He even could have made a consistent pattern, but one that didn’t match evolution’s predictions. For example, he could have given all birds protein sequences that most closely match fishes. Any of those patterns would have been absolutely devastating for evolution. Anything other than exactly the pattern that we see would have falsified our understanding of life on this planet.

My point here is simple, if you want to say that God created all life on planet earth, then what you have to say is this: God (who according to the Bible is a God of truth, not deception) had a nearly infinite number of options for how to create life, yet out of all of those options, he chose the one and only pattern that would confirm the theory of evolution. To put that another way, life looks like it evolved. You absolutely cannot say that the evidence doesn’t support evolution, because evolution’s predictions have consistently come true. You can choose to ignore the evidence, but you cannot deny that it perfectly matches evolution’s predictions. So, you are left with saying that life on planet earth looks exactly the way it would if it evolved, but it didn’t actually evolve, God just created it in the one and only way that would make it look like evolved.

In closing, I would like to ask you a simple question. If you are going to write off these genetic patterns as “just similarities,” if you are going to ignore this overwhelming evidence and these astounding predictions, then what would convince you that evolution was true? If the fact that it accurately predicted the genetic patterns of all living things isn’t enough for you, then what would be? What would it take to convince you that you were wrong?

Note: Some creationists try to contest arguments like this by pointing to cases where scientists have disagreed about how two groups of animals are related, there are, however numerous problems with that counterargument. First, in the modern genetic era, those debates usually only occur for pretty narrow taxonomic boundaries, while the overarching patterns remain undisputed. Second, those debates arise from one of two things: unclear morphology or unclear genetics. To put that another way, often what happens is that scientists are working with incomplete fossils and it is difficult to use them to determine how things are related. Thus, disagreements arise not because evolution was wrong but simply because scientists are working with incomplete data sets that have been preserved for millions of years (convergent evolution can also sometimes confound things even for living organisms). Other times, this arises from using a limited number of genetic markers. Sometimes, genetic patterns are hard to decipher, particular if you are only using a tiny portion of the genome, and these tools aren’t perfect, but as more and more studies are done using more and more markers, the picture becomes increasingly clear, and it overwhelming matches what we expect to see from evolution.

Related posts


  • Cardillo et al. 2004. A species-level phylogenetic supertree of marsupials Journal of Zoology 264:11–31.
  • ENCODE Project Consortium. 2012. An integrated encyclopedia of DNA elements in the human genome. Nature 48957–74.
  • Eyre-Walker et al. 2007. The distribution of fitness effects of new mutations. Nature Reviews Genetics 8:610–618.
  • Gallus et al. 2015. Disentangling the relationship of the Australian marsupial orders using retrotransposon and evolutionary network analysis. Genome Biology and Evoltuion 4:985-992.
  • Green et al. 2014. Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs. Science 346.
  • Rands et al. 2014. 8.2% of the human genome is constrained: variation in rates of turnover across functional element classes in the human lineage. PLoS Genetics 10:e1004525.
  • vonHoldt et al. 2010. Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication. Nature 464:898-902.


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