The Skeptics' Guide to the Universe: How to Know What's Really Real in a World Increasingly Full of Fake

by Steven Novella

If you have your smartphone handy, search for “selective attention test” on YouTube before reading on if you want to avoid spoilers.

Another follow-up study by Trafton Drew asked radiologists to read a CT scan of the lungs. He placed an obvious picture of a gorilla in a dark part of the scan. It is clearly visible, and yet 82 percent of trained radiologists missed the gorilla. Radiologists, while experts at reading such scans, are still humans. They’re not looking for a gorilla. They’re looking for tumors and other known pathology,

Another iconic video demonstrating this effect is the color (or “colour” since it’s British) changing card trick by our friend Richard Wiseman, which can be found by searching “colour changing card trick” on YouTube. Watch it and be amazed. You can also just Google “change blindness” and be rewarded with all sorts of fun.

Pareidolia refers to the process of perceiving an image in random noise, such as seeing a face in the craters and maria of the moon.

Expectation plays a huge role in this process. That’s why, once your friend says, “Hey, don’t you see the dragon in that cloud? There’s its head,” the image pops into existence. Your brain found the pattern, and its construction of that image snaps into place. Or, if someone tells you that if you play “Stairway to Heaven” backward you can hear Robert Plant say, “Here’s to my sweet Satan,” then you’ll hear the supposed devil worship.

Even on Earth there are impressive examples of pareidolia, of which the app Google Earth has made an easy pastime. My favorite is Medicine Hat, Canada, which shows a profile of a woman apparently wearing earbuds (the wire of the earbuds is an access road).

Hyperactive agency detection is the tendency to interpret events as if they were the deliberate intent of a conscious agent rather than the product of natural forces or unguided chaotic events.

The ideomotor effect is an involuntary subconscious subtle muscle movement driven by expectation, which creates the illusion that the movement is due to an external force.

The Dunning-Kruger effect describes the inability to evaluate one’s own competency, leading to a general tendency to overestimate one’s abilities.

Here comes the critical part: Now realize that you are as ignorant as the average person is in every other area of knowledge in which you are not expert. The Dunning-Kruger effect is not just about dumb people not realizing how dumb they are. It is about basic human psychology and cognitive biases. Dunning-Kruger applies to everyone.

But a good rule of thumb is to err on the side of humility. If you assume that you know relatively less than you think you do and that there is more knowledge than you are aware of, you will usually be correct.

Motivated reasoning is the biased process we use to defend a position, ideology, or belief that we hold with emotional investment.

A logical fallacy is an invalid connection between a premise and a conclusion, where the conclusion does not necessarily flow from the premise(s) but is argued as if it does.

I’ve said it before, but just because an argument isn’t sound doesn’t mean the conclusion must be false. I might argue that global warming is real because the sky is blue. That’s a non sequitur, making the argument unsound. But it may still happen to be true that global warming is a real phenomenon. When an argument isn’t sound, it simply means the argument does not support the conclusion. The conclusion may be true or false. The fallacy fallacy comes from concluding that a claim must be wrong because one argument proposed for it is not valid.

Confirmation bias is perhaps the most powerful and pervasive cognitive bias (which is why it gets its own chapter), and it’s important to understand it thoroughly. Confirmation bias is the one bias to rule all biases, the mayor of Biastown, captain of the USS Bias, the Sith Lord of the bias side of the Force (okay, you get the idea). Confirmation bias is a tendency to notice, accept, and remember information that appears to support an existing belief and to ignore, distort, explain away, or forget information that seems to contradict an existing belief. This process works undetected in the background of our minds to create the powerful illusion that the facts support our beliefs.

If it’s natural, it has to be good for you. Well, bird shit and gravel are natural, but I won’t eat them! —James “The Amazing” Randi

It is an interesting thought experiment to ask, What if we lived in a universe in which there were supernatural phenomena? We again are faced with the problem of how to define “supernatural,” as you could always argue that if the supernatural existed it would be part of nature and therefore “natural.” That’s why we have to define the supernatural by how it behaves, not by what it is.

Postmodernism, as it applies to science, is the philosophical position that science is nothing more than a cultural narrative and therefore has no special or privileged relationship with the truth.

Postmodernism, in practice, is the ultimate sour grapes of science deniers—“Well, all science is socially constructed anyway.” Add in a little talk about fascism and oppression and you can make it all seem socially conscious.

One of the originators of postmodernist philosophy is Thomas Kuhn, who wrote The Structure of Scientific Revolutions in 1962. It was in that book that Kuhn introduced the word “paradigm” to the world.

There are two main criticisms of the Kuhnian postmodernist position. The first is that it is a false dichotomy. You can’t separate scientific progress cleanly into normal incremental change within a paradigm and dramatic paradigm shifts. Rather, scientific change occurs along a continuum. Some discoveries are bigger and more disruptive than others, but you can’t lump them into two categories. The second and more devastating criticism of the postmodernist position is that this interpretation of the history of science confuses the context of discovery with the context of later justification. It actually doesn’t matter how scientists come up with their ideas. They can get them from science fiction, popular culture, or a drug trip. It simply doesn’t matter. What does matter is how those ideas are tested—later justification.

The principle of Occam’s razor, attributed to William of Ockham (1287–1347), states that when two or more hypotheses are consistent with the available data, then the hypothesis that introduces the fewest new assumptions should be preferred. In the original Latin, “Non sunt multiplicanda entia sine necessitate,” which translates to “Entities must not be multiplied without necessity.”

Pseudoscience refers to claims and procedures that superficially resemble science but lack the true essence of the scientific method. In practice there is a continuum from rank pseudoscience at one end to rigorous science at the other, with no sharp demarcation line in between.

Science is hard, and getting harder. We’ve picked most of the low-hanging fruit, answered all the big and easy questions, and we are now engaged in complex research to address more and more sophisticated and subtle scientific questions.

People tend to use themselves for calibration—anyone more skeptical than you is a denier, and anyone less skeptical than you is a true believer.

Doubt is key to skepticism and science. The absence of doubt is gullibility. This feature, most of all, is what makes denialism pseudoskepticism. The problem with the denialist approach is that doubt is not used as a tool of honest questioning but rather for undermining a belief one doesn’t like.

Of course, there is always doubt in science. Science is never 100 percent certain about anything, because science is not about certainty. It’s not even really about proving things, but rather disproving them. Science is also not directly about truth, but rather about building testable models that predict how the universe behaves.

Here is the question: What is the predictive value of a positive mammogram in a forty-year-old woman, or what are the odds that she actually has breast cancer because her mammogram was positive? With a 90 percent specificity you might be tempted to say 90 percent, but that would be wrong. The real answer is 7.5 percent. This is because 99 out of 100 forty-year-old women do not have breast cancer, so with a 10 percent false-positive rate there will be about 10 women out of 100 who test positive but don’t have breast cancer. Only about 0.8 of the 1 in 100 women who have breast cancer will test positive. So, out of 100 women, 9.9 will test positive but be negative, and 0.8 will test positive and be positive. So if you are a forty-year-old woman and test positive, chances are much greater it’s a false positive (0.8 true positive / 10.7 total positive x 100 = 7.5%).

There are many who think there is currently a replication problem in science. In a 2016 study published in Nature, 52 percent of scientists surveyed reported this belief based on their own inability to replicate the work of others.

Most people are opportunistic conspiracy theorists. We tend to accept conspiracies ad hoc when it suits our beliefs. This is most obvious when it comes to political ideology.

Here are some common conspiracy theories with the percentage of believers, according to Public Policy Polling: • 20 percent of voters believe there is a link between childhood vaccines and autism, 46 percent do not. • 7 percent of voters think the moon landing was faked. • 13 percent of voters think Barack Obama is the Antichrist, including 20 percent of Republicans. • Voters are split 44 percent to 45 percent on whether President Bush intentionally misled us about weapons of mass destruction in Iraq. 72 percent of Democrats think Bush lied about WMDs, Independents agree 48–45 percent, but just 13 percent of Republicans think so. • 29 percent of voters believe aliens exist and are visiting the Earth. • 14 percent of voters say the CIA was instrumental in creating the crack cocaine epidemic in America’s inner cities in the 1980s. • 9 percent of voters think the government adds fluoride to our water supply for sinister reasons (not just dental health). • 4 percent of voters say they believe “lizard people” control our societies by gaining political power. • 51 percent of voters say a conspiracy was at work in the JFK assassination, whereas just 25 percent say Oswald acted alone.

The Hawthorne or observer effect refers to the fact that simply observing something may alter its behavior, thereby creating an artifact that leads to an incorrect conclusion.

Intelligent design holds that certain features of the universe and of living things were caused by an intelligent agent who, for reasons we do not care to get into, chose to make the world look exactly as if it were the product of random variation and natural selection.

Blondlot reported that N-rays were produced by many types of matter, both living and inert (everything except green wood and some treated metals), and that their strength increased with the “psychic activity” of the source. His experimental setup included a hot wire inside an iron tube to generate the N-rays, which were then refracted through a 60-degree angle prism of aluminum, and in turn were detected by a calcium sulfide thread that would glow slightly. The subtle glow could only be perceived in the dark by those with sharp vision.

“Do X and you will be happy.” I know that journalists often don’t write their own headlines and that there is a circle in skeptical hell dedicated to headline writers where they are tormented by the twin demons Hype and Sensationalism.

This is not a f***ing self-help book.

To close out, we’d like to leave you with one final thought: Don’t trust us. This might sound strange after reading the book, but the point is, you shouldn’t really trust anyone when it comes to empirical knowledge.