It is good to be skeptical about everything that you hear and read. In fact, skepticism is one of the defining characteristics of a scientist. Nevertheless, terms like “skeptic” and “open-minded” are often misappropriated by people in the anti-science movement, and many of the most biased people on the planet are under the delusion that they are skeptical. Climate change deniers, for example, often refer to themselves as, “climate change skeptics,” and it is rare to have a conversation with anti-vaccers without them referring to pro-vaccers as “sheeple.” Therefore, I want to briefly examine what it actually means to be a skeptic.

First, I want to clear up a common misconception. Many people seem to be under the impression that being a skeptic means going against the mainstream view. Thus, anti-vaccers consider themselves to be “thinking parents,” while viewing everyone else as “sheeple.” There is, however, nothing in the definition of “skeptic” that requires you to reject a scientific consensus. You are welcome to accept a consensus as long as that consensus formed as a result of strong, scientific evidence.

Having cleared up that misconception, let’s move on to the definition of a skeptic. There are basically two parts to being a skeptic. First, a true skeptic does not accept something or commit to a position unless there is sufficient evidence for that position. In other words, a skeptic questions what he/she is told and doesn’t accept anything until they have carefully studied the issue and examined the available evidence. Importantly, you must use good sources when fact checking. So, for example, reading Natural News does not constitute examining the evidence. Rather, you need to look at the original, peer-reviewed research.

This first requirement of skepticism may sound simple, but it is something that most people struggle with (including people who strongly support science). It is very easy and tempting to quickly latch onto some new study that seems to support your position, but it is crucially important that you avoid this trap. You must always carefully examine the evidence regardless of whether or not it supports your position. This is, in fact, one of the most important things that students of science get taught in graduate school. The peer-review system works well, but it is far from perfect, and sometimes bad research does get published. Therefore, you can never assume that something is true, and you must rigorously and carefully examine everything before accepting or rejecting it.

The second prerequisite for skepticism is being open-minded. This simply means that you are willing to change your position if you are shown evidence to the contrary. The term, “open-minded” has, however, been stolen and perverted by the anti-science movement. On numerous occasions, I have had people tell me that I need “open my mind about alternative medicines.” The reality is that am completely open to the possibility that alternative medicines work, but I’m not going to accept that they work until they have passed rigorous scientific testing. That’s not being close-minded, that’s being skeptical. Similarly, I have had multiple anti-vaccers tell me that my training in the sciences has made me, “close-minded.” When I pressed these people for what they meant , they explained that I was being close-minded by demanding scientific studies and refusing to accept anecdotal evidence. Think about this for a second. According to them, those of us who argue in favor of science are close-minded because we demand scientific evidence for a debate about science. Further, these same people will usually proudly proclaim that nothing will ever change their minds, which is, of course, the very definition of close-minded.

Accepting something without sufficient evidence is not being open-minded, it’s being gullible. It is not, for example, open-minded to use anecdotal evidence to arrive at the conclusion that vaccines cause autism. Rather, someone who is open-minded would reject those anecdotal reports in favor of the large, carefully controlled studies which clearly show that vaccines do not cause autism. It is important to note, however, that nothing in science is ever 100% certain. Thus, being truly open-minded means that you are always willing to consider the possibility that you might be wrong no matter how clear the data currently seem. So, for example, if in the future a large, well designed, carefully controlled study is published showing that vaccines do cause autism, and the results of that study are replicated by other researchers, I promise you that skeptics around the world (myself included) will write and prominently display posts admitting that we were wrong about the relationship between vaccines and autism. That is what it truly means to be open-minded. It means that you are willing o change your view when presented with good evidence. It does not mean that you are willing to blindly accept something despite a lack of evidence.

In summary, a skeptic is simply someone who demands good evidence before accepting something and is willing to change their view when it conflicts with the evidence. These requirements are easy to say, but often hard to follow. Nevertheless, everyone should strive to be a skeptic. You should use good sources, question your assumptions, demand evidence, beware of cognitive biases, and above all else, never hold any position so dearly that you are not willing to challenge it.