Skepticism vs Pseudoskepticsm

The image below is a fake image. It's reported to be an image of a rainbow that was posted on the David Attenborough Club (apparently maintained by Hasan Jasim) and attributed to Lloyd Ferraro. According to at least one source, Lloyd Ferraro is a pilot who took this image at 30,000 ft while flying a plane. "According to Ferraro, he was flying over the Pacific Ocean when he spotted the rainbow and decided to capture the moment on camera. The resulting photograph has since gone viral, captivating people around the world with its beauty and rarity." However, there is no doubt that the rainbow in this image is photoshopped or (perhaps more likely) AI-generated. 

There are at least three ways we know this is the case. First, we see rainbows when looking in the direction of our shadow. It's not possible to see a rainbow when the sun is in front of you, as is basically the case in this image. Second, the primary red ring of a rainbow forms at a 42° angle, relative to your point of view, and in double rainbows, the  primary red ring of the second rainbow forms at a 52° angle. What this means necessarily is that when you view (or a camera photographs) a rainbow, it will always appear that you are looking directly at it. You will never see a rainbow that looks like you're at an angle to it, as you see in the image above, where the rainbow appears to be "facing" slightly up and to the left.  And third, the bases of cumulous clouds form between 1,000 and 6,500 ft, so you would never look up at a cumulous cloud at 30,000 ft. In other words, if you know a bit about physics, there is sufficient evidence in this photo that requires the conclusion that this is a fake image of a rainbow.

Now not everyone knows precisely how rainbows work and would not immediately know that this image is fake, and this is where skepticism comes in. A skeptic will see this image and not immediately click "share" and promote the idea that this is a real image of a rainbow. Skeptics know that photoshop  (and now AI) is capable of doing some amazing things, and there's a possibility that this image is fake. A few minutes researching the physics of rainbows, however, will let anyone determine that this is not a real image. Skepticism, at minimum, is the practice of using critical thinking, such that we do not simply accept what we're told, but evaluate claims on the basis of evidence and data. Skepticism saves us from the embarrassment of sharing a fake image as if it's real and then finding out afterwards that we were promoting what is objectively false. 

By contrast, the image below shows what a full rainbow would actually look like if photographed with a real camera and not manufactured by photoshop or AI. This photo was taken by Lukas Moesch and was featured by NASA in their Astronomy Picture of the Day.

NASA offered the following explanation for the image. "Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360-degree circle of a rainbow is more commonly visible. Pictured here, a full-circle rainbow was captured over the Lofoten Islands of Norway in September by a drone passing through a rain shower. An observer-dependent phenomenon primarily caused by the internal reflection of sunlight by raindrops, the rainbow has a full diameter of 84 degrees. The Sun is in the exact opposite direction from the rainbow's center. As a bonus, a second rainbow that was more faint and color-reversed was visible outside the first." Now I can offer no absolute proof that Moesch's image isn't also fake. All I can say is that this photograph agrees with known physics about how rainbows work, it has passed scrutiny by a reputable source (NASA), and there's no  reason to think that this image is fake. As a skeptic, there is no rational basis for concluding that this image is a fake image.

Now suppose that someone seeing the first image from Ferraro believes it to be a real image, and then when shown how it violates known principles of physics, concludes that the physics must be wrong because here is an image of a rainbow that proves that rainbows don't always conform to what physicists say. NASA and other scientific organizations must be lying because here is evidence that physics doesn't behave as physicists tell us it behaves. The physicists must be lying, and Moesch's image may well be the fake image, fabricated to support NASA's lie, since Ferraro's image is real (and he hasn't been bought by politicians). If you ask this person for evidence that physics is wrong, that Moesch's image is fake, and that Ferraro's image is real, you don't get any evidence at all - just bare assertions and accusations that NASA (and others) are lying. This is what should be called pseudo-skepticism. Pseudo-skepticism is the practice of accepting what is demonstrably wrong and rejecting sound evidence, all in the name of skepticism. 

In climate science, we see pseudo-skepticism all the time in the contrarian movement. The basic thrust of contrarian pseudo-skepticism is that climate science is wrong about AGW because of claims made by other contrarians about which the contrarian refuses to be skeptical. I've been compiling a list of these pseudo-skeptical claims and offering rebuttals to them.  As one example, one contrarian claim is that AGW cannot be valid because there is no correlation between CO2 and global temperatures. As "evidence" for this lack of correlation, you may see contrarians posting the local temperature from a single proxy in Greenland as if they are global temperatures. You may also see incompetently plotted graphs of CO2 and temperature across the Phanerozoic. But there is a valid way to test whether there is a correlation between CO2 and temperature, and that is to plot and calculate the correlation. If you plot HadCRUT5 with respect to the 1850-1900 mean and CO2 radiative forcings (calculated from CO2 concentrations at 5.35*ln(rCO2)), you come up with an r^2 of 0.872, which is about what you'd expect if CO2 is driving temperature changes with influences from natural variability due to ENSO and other factors.

Now this does not prove that CO2 is driving global warming, since correlation in and of it self is not proof of causation. But at the same time, we can conclusively rule out the pseudo-skeptical claim that CO2 and GMST are not correlated since 1850. And we can still go beyond correlation to causation using multiple lines of evidence, including long-term data for CO2 and GMST and observational evidence of the greenhouse effect. Does this additional evidence prove AGW? No. Proof is useful in math and alcohol, but in science, we're always dealing with probabilities. Any theory (AGW included) can in principle be falsified by an experiment that shows it to be false. But the reality is that the evidence for AGW is overwhelming, there is no compelling evidence that it is wrong, and there is no evidence of any global conspiracy fabricating the overwhelming evidence in the peer-reviewed literature. 

This kind of pseudo-skepticism is not limited to a subset of contrarians in climate science. It's found frequently when there are groups of people with ideological objections to positions that are supported by an overwhelming amount of empirical evidence. We see it among "flat earthers" and among those that think vaccines cause autism as well as among some who are opposed to climate science. I've even seen it in some articles written in opposition to the Big Bang. Whenever our ideologies are unquestionable, we run the risk of selectively accepting what confirms our beliefs and rejecting what contradicts them.

Skeptics accept the best available evidence with calculated uncertainties for what it is and continue to use the scientific method to test and critically evaluate theories and hypotheses, but they are careful to avoid the pseudo-skepticism found so frequently in contrarian talking points about climate. And to be fair, proponents of AGW sometimes fail at skepticism as well, when we do not check up on news stories that are sensationalistic and/or exaggerate the findings of studies, but I'm covering this in another post.