Psychological research finds that inoculation is an effective way to build public resilience against misinformation. But how do you put that in practice? An important element to building inoculating messages is critical thinking. In 2018, I collaborated with critical thinking philosophers to develop a methodology for deconstructing and analyzing misinformation, as a system way to identify reasoning fallacies. We applied our methodology to misinformation about climate change but this approach is applicable to misinformation in all topics. While I recommend everyone read the full paper, if you only have 3 minutes, I strongly recommend watching our Critical Thinking Cafe video which both introduces our methodology and is good fun!

You can check out the complete, comprehensive methodology in the paper, but for this post, I want to present a simplified version with the most important elements. Basically, in order to assess whether a claim is misinformation containing reasoning fallacies, there are several steps to go through:

Construct an argument structure: break the claim up into its starting assumptions (or premises) and its conclusion. Check logical validity: once you have the argument structure, check whether the conclusion logically follows from the premises. Check if the premises are true: if the argument is logically valid, then check if the premises are true.

Let me illustrate this methodology with an example – the argument that there’s no scientific consensus on human-caused global warming because 31,000 scientists signed the dissenting Global Warming Petition Project. Research by Sander van der Linden found that this is one of the most potent climate myths in reducing acceptance of climate change, perceived consensus, and support for climate action.

First, let’s deconstruct this claim by laying out its premises and conclusion. This claim contains two premises: first, a large proportion of scientists dissent against human-caused global warming, and second, people with a science degree are experts on climate change. The conclusion is that there’s no expert consensus on human-caused global warming.

Second, is this argument logically valid? In other words, if the two premises were true, would it logically follow that the conclusion was true? In this case, yes – if a large proportion of science graduates dissent and science graduates are climate experts, then there would be no expert consensus. Having established logical validity, we now move to the next step.

Third, are the premises valid? The first premise is that 31,000 science graduates amounts to a large proportion of science graduates. But there are over 10 million science graduations in the U.S. and 31,000 is only a fraction of a percentage. This premise commits the denialist technique of Magnified Minority, amplifying the significance of a small dissenting minority.

The second premise is that science graduates are automatically experts in climate change. This premise commits the fallacy of fake experts – people who convey the impression of scientific expertise but don’t possess the relevant expertise. Because the Global Warming Petition Project can be signed by anyone with a science degree, it’s signed by graduates in computer science, veterinary science, mechanical engineering, and other science fields – but very few actual climate scientists. In fact, 99.9% of the signatories have no expertise in climate science. This argument is fake experts in bulk.

In this example, our critical thinking methodology enabled us to identify the two ways that the Global Warming Petition Project misleads the public – through the denialist techniques of Magnified Minority and Fake Experts.

The sharp-eyed among you may have noticed that earlier, I glossed over one part of the critical thinking methodology. What do you do if the argument is logically invalid? This is usually because the argument contains a hidden or unstated assumption. In this case, you need to add the hidden premise that will transform the argument to being logically valid.

Let’s look at another common climate myth, the argument that climate has changed naturally in the past so current climate change must also be natural. If we deconstruct this claim into an argument structure, it contains two premises: first, climate has changed naturally in the past, and second, the climate is currently changing. The conclusion is that current climate change is naturally caused.

Now that we can examine this claim’s argument structure, we see that the conclusion doesn’t follow from the premises. Just because nature caused climate change in the past doesn’t mean that it necessarily has to be the cause of modern climate change now. This argument is logically invalid.

What is the hidden premise that will make this argument logically valid? We need to add a third premise: the assumption that past drivers of climate change must be the same as current drivers of climate change. With the third premise added, this makes the argument logically valid. Now we can check whether the premises are true.

The first premise – climate has changed naturally in the past – is true. The second premise – climate is currently changing – is also true. But the third premise – past drivers are the same as current drivers – commits the single cause fallacy. It assumes that only one factor drives climate change when there can be multiple factors (incidentally, to see video of Peter Ellerton walking through this process, I again direct you to our Critical Thinking Cafe video).

These two examples – analyzing logically invalid arguments or logically valid arguments with false premises – cover much of the misinformation you’re likely to encounter. However, there are other nuances this blog post doesn’t cover, such as inductive misinformation and the fallacy of equivocation – that you can read more about in our full paper.

Lastly, I will point out that critical thinking is not easy – it’s equivalent to learning a new language so you can’t expect to become a master after a single webinar or blog post. Part of learning critical thinking is putting names to the concepts and denial techniques to be found in misinformation. A useful framework for identifying fallacies and denial techniques is the FLICC taxonomy. I’ll cover that in my next blog post.