Skip to content
Home » Scientific facts vs personal opinion about vaccines, evolution, climate change

Scientific facts vs personal opinion about vaccines, evolution, climate change

When I write, I usually stick to scientific facts that are supported by evidence published in peer-reviewed biomedical journals. Because I can be rather blunt about a scientific topic, for example, stating that evolution is a fact, it may sound like I’m saying “my opinion is that evolution is a fact.” No, it’s a scientific fact, not a personal opinion.

When it comes to opinions vs scientific facts, there is a difference, a huge difference. An opinion is a preference for or judgment of something, generally supported by weak evidence. Or sometimes no evidence. A scientific fact only exists because there is a vast amount of supporting evidence.

My favorite color is blue or green, depending on the day. I think that mint and mushrooms taste horrible, and I can’t imagine what they’d taste like together. Doctor Who is boring. Soccer is even more boring to the point of inducing depression. These are all my opinions, meaning that evidence, especially the scientific kind, probably could not be found to support any of them (see Note 1).

Opinions may be unique to me alone or massively shared across the general population but they all have one thing in common – they cannot be verified by evidence, except that I believe them.

As Jef Rouner wrote in the Houston Press,

There’s nothing wrong with an opinion on those things. The problem comes from people whose opinions are actually misconceptions. If you think vaccines cause autism you are expressing something factually wrong, not an opinion. The fact that you may still believe that vaccines cause autism does not move your misconception into the realm of valid opinion. Nor does the fact that many others share this opinion give it any more validity.

On the other side are scientific facts, which only exist because of evidence – unbiased evidence, along with well-designed experiments that give us that evidence. Let’s take a look at opinions vs scientific facts, just in case you think they are equivalent.

Photo by CDC on Unsplash

Scientific facts

When I write about scientific facts, I spend hours searching and actually reading sources (there’s something novel because I have an opinion that most people don’t read beyond headlines). I see where the evidence leads me. Of course, I’m not going to spend a lifetime reading every article about evolution, because there must be literally millions of articles published about it.

The scientific consensus on evolution is well established, and who am I to provide any evidence contradicting it? I’m not an arrogant narcissist who thinks my own rhetoric contradicts said facts about evolution.

There are many other areas of science that are factual:

  • Human-caused climate change. A fact.
  • Safety and effectiveness of vaccines. A fact.
  • The earth is over 4.5 billion years old. A fact.
  • Safety of GMO foods. A fact.
  • MSG doesn’t do anything to humans. A fact.
  • Gravity causes large objects to move toward each other. A fact.

I could go on and on and on. There are probably thousands of scientific facts regarding common daily observations of the natural world.

But what makes a scientific fact?  A fact, in science, means a conclusion that is supported by data, or evidence. It does not state absolute certainty; however, the data or evidence are confirmed to such a level that it would be ridiculous to withhold support for such a fact. And, to make this clear, only new high-quality and quantity of evidence can change this fact.

One important point, because they sometimes get confused – a scientific theory is a well-substantiated explanation of scientific facts. In other words, the theory explains how facts became facts.

For example, the facts of evolution come from observational evidence of current processes, from similarities in organisms that indicate descent from a common ancestor to transitions in the fossil record (yes there are millions of transitional fossils, despite what creationists babble on about). Theories of evolution provide a provisional explanation for these facts.

Here’s one more thing about scientific facts. You do not get to stand by the sidelines and pontificate about the validity of these facts. You do not get to say “that’s wrong.”

Well, we do have free speech in the USA, so go for it, say climate change is wrong. Or a conspiracy. Or a lie. Or that it’s snowing, so it’s wrong. Or whatever you want. But without the evidence of equivalent quality AND quantity derived from climate change science, you’d be wrong. I keep saying that if someone wants to change the consensus on a scientific fact, bring evidence – but it better be something beyond opinion and rhetoric.

scientific facts
Photo by Dmitry Vechorko on Unsplash

Opinions vs scientific facts

So what are opinions vs scientific facts – how can we tell?

There’s nothing wrong with an opinion about something when that opinion cannot be objectively and scientifically supported. In fact, in the scientific method, an opinion could be like a hypothesis, and through experimentation, one could conceivably turn an opinion into fact. But don’t conflate them.

Soccer is boring to me, but that’s subjective. Maybe it’s boring to me because of the low scores, the fake injuries, or it is foreign (literally and culturally). But, I’m smart enough to know that objectively, someone could say that baseball is boring (see Note 2). Or ice hockey (see Note 3). Or any other sport. Everyone has an opinion about all sports, and all of those opinions are equally correct and equally wrong.

The problem with opinions arises when people conflate those opinions, which are based on anything but evidence, with facts. If you have the opinion that vaccines cause autism, you are expressing something that is factually wrong – it is not an opinion. You are scientifically and objectively wrong, based on mountains of evidence.

Even if you believe that your opinion is right, it does not make it so. It’s still wrong. And just because you can troll the internet to find others who share that misconception, again does not move it into the realm of fact. It merely means you’ve found like-minded people who are also wrong. Your wrong opinion is still wrong, and it has no validity. None.

In an episode of John Oliver’s Last Week Tonight, he referenced a Gallup poll showing one in four Americans believe climate change isn’t real:

Who gives a shit? You don’t need people’s opinion on a fact. You might as well have a poll asking: “Which number is bigger, 15 or 5?” or “Do owls exist?” or “Are there hats?”

If 25% of Americans believe climate change isn’t real, who cares? They are wrong, period, end of the story.

If 10% of Americans think that vaccines cause autism, who cares? The real evidence says that they are wrong, but worse yet, like the climate change deniers, they attempt to influence these discussions with opinions that are simply wrong. How much time do we spend discussing vaccines and autism, or the fact of climate change, with deniers, when we need to vaccinate children and do something about stopping the environmental disaster of climate change?

One more thing. Science doesn’t have opinions. It’s a method to provide evidence that supports or refutes a hypothesis. It’s data, and data only. So science doesn’t have an opinion about climate change, it has overwhelming evidence that man causes it. Science does not have an opinion about vaccines, it has overwhelming evidence that they are safe and effective.

Oh, one more thing after that. Because it has no opinions, there are no debates (in a general sense, sometimes there’s debate about data and conclusions from data). Once there’s a scientific consensus, the debate is over. Don’t conflate political debate with scientific debate.

Vaccines, evolution, climate change, the safety of GMOs, and a whole host of other “controversial” topics are settled science. If you want to change that science, then get up off the couch in your mom’s basement, get a college degree in science, then get a Ph.D. in a science related to the settled science that you want to change, spend 2-3 years in post-doctoral studies, join a world-class science lab, publish 5-10 articles in established, respected science journals, and after all of that you can change the settled science, we can talk. Plus you might win a Nobel Prize.

But sniping from the sidelines with your weak, unsupported personal opinions means nothing to those of us who did the hard work.


  1. Except for soccer. I know there’s evidence somewhere that supports my beliefs about the dullness of soccer.
  2. That’s a wrong opinion.
  3. Also a wrong opinion.
Michael Simpson

Don’t miss each new article!

We don’t spam! Read our privacy policy for more info.

Liked it? Take a second to support Michael Simpson on Patreon!
Become a patron at Patreon!