In debates, I often ask people what it would take to convince them that they were wrong, and, much to my amazement, they frequently tell me that nothing will ever make them change their minds. What’s even more astounding is that they often seem proud of this fact as if it somehow shows the strength of their position. The reality is that anytime that someone proclaims this, they have just made it clear that they are not following the laws of logic and are actually basing their views on biases, not evidence. In fact, refusing to consider contrary evidence is the very definition of close-mindedness.

There is an old story that when Galileo was arguing for heliocentrism, he took one of his opponents onto his roof and offered him a telescope so that he could see the evidence for himself; however, this man was so convinced that Galileo was wrong that he refused to even look through the telescope. The story itself is probably just a legend, but it nevertheless nicely illustrates the problem. It is irrational to hold any view so tightly that you aren’t willing to admit the possibility that you might be wrong. To convince yourself of this, I want you think about a view that you are very, very certain is correct. Now, imagine someone who opposes that view stating that they are so convinced that you are wrong that there is nothing that can persuade them otherwise. You would clearly disagree with this person. You would think that they are close-minded for refusing to even consider the evidence for your position. So, if you think that they are foolish for refusing to look at the evidence, you must also apply that reasoning to your own views. In other words, if it is illogical for them to blindly write off all contrary evidence, then it must also be illogical for you blindly write off all contrary evidence.

The core problem here is that anytime that you proclaim that nothing will convince you that you are wrong, you have just established an unfalsifiable view, and falsifiability is one of the cornerstones of science. Falsifiability simply means that it would be possible to disprove a view if it actually is incorrect. Cell theory provides an excellent example of this concept. Cell theory states that all living things are made of cells. This theory is falsifiable because the discovery of a single organism that was not made of cells would discredit it. In other words, if the theory is wrong, then it is possible to discredit it by examining the organism that defies it. Thus, the appropriate response to, “what would it take to convince you that that you were wrong about cell theory?” would be, “an organism that is not made of cells.” To put this another way, cell theory is falsifiable because if it wasn’t true, it would be possible to demonstrate that.

Falsifiability is extremely important because it provides a vital mechanism for determining if something isn’t true. In other words, if something isn’t falsifiable then it is impossible to disprove it no matter how truly absurd it is. Young earth creationists present one of the best illustrations of this problem. For example, during the much publicized Bill Nye vs. Ken Ham debate, both orators were asked what it would take to make them change their minds. Ham gave a long, rambling response which can be summed up as, “nothing.” Meanwhile, Bill Nye gave the response of a true skeptic:

“We would need just one piece of evidence. We would need the fossil that swam from one layer to another. We would need evidence that the universe is not expanding. We would need evidence that the stars appear to be far away but are not. We would need evidence that rock layers could somehow form in just 4,000 years….We would need evidence that somehow you can reset atomic clocks and keep neutrons from becoming protons. Bring on any of those things and you would change me immediately.”

The difference between these two responses is a critical one and it illustrates the reason why creationism is pseudoscience. Creationists like to claim that they are doing valid science, but this is clearly nonsense because they are starting with the conclusion that evolution isn’t true, then trying to make the evidence fit that conclusion. The problem with this should be obvious: no matter how clearly flawed creationism is, they will never accept the evidence that opposes it (i.e., their view is not falsifiable). So, for example, when they are presented with the fact that corals grow much too slowly to have formed in a few thousand years, they generally assert that corals used to have a much, much faster growth rate. Similarly, they claim that radiometric decay isn’t constant (even though there is no evidence to support that position), and they assert that the flood somehow sorted varves at a rate of over 10 per minute. All of these arguments (and many others I didn’t mention) are ad hoc fallacies, and they illustrate the fundamental problem with asserting that nothing will change your mind. Namely, it is always possible to come up with an ad hoc explanation for something that opposes your preconceived view, but just because you can propose an answer doesn’t mean that your proposal is logical. For example, I could propose that aliens caused varves, accelerated radiometric decay, etc., but unless I can provide evidence for that claim, it is an ad hoc fallacy. Even so, until creationists can provide evidence for their claims, their arguments are logically invalid.

This problem is, of course, not limited to creationism. Opponents of GMOs, vaccines, modern medicine, global warming, etc. regularly fall into this trap. They routinely disregard any study that opposes their view, and when asked why they ignore those studies, they generally claim that the authors had an agenda, were paid off, etc. This is not a rational response. The rational response is to actually engage contrary information and truly consider whether or not your view is correct.

An excellent example of this blind rejection of facts happened recently when a large review of studies on homeopathy failed to find any evidence that homeopathy worked. Despite the fact that this paper used an independent contractor in order to avoid biases, the response from homeopaths was swift and predictable: they chalked it up to a conspiracy by pharmaceutical companies and the medical establishment to suppress homeopathy (at least that seems to be the prevailing opinion on the forums and blogs that I visited). This is clearly not a rational response because the burden of proof is on homeopaths to provide evidence that the review is the result of a massive conspiracy. The rational response is to actually consider the evidence presented in the paper rather than simply writing it off as a conspiracy.

At this point, some people object to my criticisms and say that they are not proclaiming that nothing will change their minds because they are biased, but rather because they have already considered the issue and know that they are right. For example, on numerous occasions I have had anti-vaccers tell me that they have done thousands of hours of research and reviewed all of the evidence and it is so convincing that nothing will ever change their minds. There are three problems here. First, it is the epitome of hubris and arrogance to assume that you are infallible, and that is exactly what this claim is doing. You must always acknowledge the possibility that you may have made a mistake. Second, this claim is based on the assumption that you have actually reviewed all of the evidence, but given the enormous volume of papers on vaccines, climate change, etc. this is extremely unlikely. Finally, even if you have truly examined all of the current evidence, you have just excluded the possibility that future studies will discredit the current views.

Science is a gradual process of falsification, and it always allows the possibility that the current evidence is incorrect. So, for example, the current scientific literature very clearly shows that vaccines do not cause autism. This has been documented numerous times, but that does not give me the right to proclaim that nothing will ever convince me that vaccines cause autism. Although it is extremely unlikely that all of the studies showing that vaccines don’t cause autism were flawed, as a scientist and rational person, I must acknowledge that there is that possibility (albeit an extremely, extremely remote one). So if you were to ask me what it would take for me to change my mind about vaccines and autism, I would respond that it would take several high quality, carefully controlled studies with large samples sizes that found a causal link between the two and offered a plausible explanation for why so many previous studies failed to find the link. Again, this is a critical distinction between scientists and anti-scientists. Scientists are interested in understanding the way that things actually are, whereas anti-scientists tend to care only about promoting their personal views even if that means committing ad hoc fallacies, proposing unknown mechanisms, and assuming that the entire scientific community is involved in a massive conspiracy.

My point in all of this is really quite simple: for all of your views, you must stop and ask yourself what it would take to convince you that you were wrong. Regardless of whether you are a pro-vaccer, anti-vaccer, creationist, evolutionist, etc., if your answer is that nothing will convince you that you’re wrong, then you are not adhering to the rules of logic or scientific analysis and you are, by definition, close-minded. If you are truly honest with yourself, you must admit that you are fallible and, therefore, you are probably wrong about at least some of your views. It is almost inconceivable that anyone is actually right 100% of the time. Further, there is no a priori way to know which of your views are correct and which of your views are incorrect. In other words, some of your views are almost certainly wrong, but you don’t know which ones are. Therefore, you must always be willing to admit the possibility that you are wrong, and you must always be willing to truly consider contrary evidence and arguments. You should never hold a position so closely that you aren’t willing to challenge it.