A paradox is an absurd or self-contradictory statement, so by definition, it’s liable to make your head spin. We’ve got one of the most ancient paradoxes there is, and it’s certainly no different. It’s called the liar paradox.
The liar paradox, also known as the liar sentence, states “this sentence is false.” If that statement makes you go a little crazy, you’re not the first. The liar paradox first came about in ancient Greece, and philosophers have been puzzling over it ever since. It’s even said that the gravestone of scholar Philetas of Cos, from the third century B.C.E., is engraved with the words “‘Twas the Liar who made me die, And the bad nights caused thereby.”
There are many other versions of this ancient puzzle. The French philosopher Jean Buridan used its contradictory logic in his proof of God’s existence: “God exists. None of the sentences in this pair are true.” There’s also the self-referential chain, “The following sentence is true. The following sentence is true. The first sentence in this list is false.”
Here’s why the liar paradox causes philosophers so much grief: if the sentence is true, then it must be false. But if the sentence is false, then it must be true. That’s what makes it a paradox. It’s an argument that leads to a self-contradictory conclusion. There are probably as many schools of thought on how to solve this paradox as there are philosophers in the world, but one thing is true (not false!): it highlights the limitations of classical logic.
Can you come up with the answers to these questions?
1. How many of each animal did Moses take on the Ark? 2. What’s the nationality of Thomas Edison, inventor of the telephone? 3. What were the first words uttered by Louis Armstrong when he set foot on the moon?
If you answered “two,” “American,” and “One small step for man …” congratulations: You got every question wrong. As we’re sure you’re aware, it was Noah, not Moses, who built the Ark; Alexander Graham Bell who invented the telephone; and Neil Armstrong, not Louis Armstrong, who went to the moon. You knew that, of course. So why did the questions fool you? It’s all in how your brain processes information.
This bit of trickery is called the Moses Illusion. It shows how bad you are at picking up on errors in your everyday life. Researchers have fooled countless volunteers in countless labs while trying to figure out what circumstances make this happen and what they can do to help people spot more falsehoods. In the original 1981 study demonstrating this illusion, more than 80 percent of people missed the fact that Moses wasn’t involved in the Ark even though they had previously proven that they knew that. That’s despite the fact that identifying erroneous questions like this was literally one of their tasks; they either had to answer the question, say “don’t know,” or say “wrong” if there was something wrong with the question.
The Moses question tripped people up the most — only around 40 percent of people were fooled by questions like “What was the nationality of Thomas Edison, inventor of the telephone?” A study published in 2000 in the journal Psychological Science explains why. UCLA researchers figured out that there are two ways people are easily fooled by this illusion: if the swapped names are “semantically similar” (on the same topic, the way Moses and Noah are both from the Bible) or “phonologically similar” (sound the same, the way Moses and Noah are both two syllables with an emphasis on the first syllable, which has an “o” sound). With that discovery, the researchers came up with questions that had both qualities in order to test what they called the “Mega-Moses illusion.” Sure enough, a question that swapped out the name “Andrew Johnson” for “Lyndon Johnson” — also a former U.S. vice president with a two-syllable first name and the same last name — fooled more people than questions with just one of those elements at play.
Sure, it’s easy to fool people. But is this actually important beyond letting a few scientists have a laugh? Unfortunately, yes. Vanderbilt psychology professor Lisa Fazio, who wrote about this phenomenon in The Conversation, has shown in her own studies that illusions like this can lead people to pick up false information about the world. When she and her team had people read fictional stories that referred to things like “paddling around the largest ocean, the Atlantic,” people were more likely to say the Atlantic was the world’s largest ocean, even though they had correctly answered “Pacific” on a test they took two weeks before reading the stories.
Luckily, the thing that’s been proven to work is a practice we can all do, especially as we wade through social-media feeds full of sensational headlines and “fake news.” When people are asked to play fact-checker, correcting errors as they read, they’re much less likely to pick up false information than people who just read what they’re given. The takeaway is clear: assume anything you hear or read could be wrong, and you’re more likely to notice when it is. If you do that, you’ll be just like Einstein, the inventor of electricity.
The next time a “Wow!” Signal comes from space — and the science community begins chattering about aliens — there’s an updated scale available to help you decide whether to listen to them. Called the Rio Scale 2.0, it’s a measure of how close a piece of scientific research comes to finding alien life. The higher the mark, the more you should pay attention.
The trouble with social media is it can easily blow the smallest news stories way out of proportion. The science community wants to take more responsibility for how they present their findings. Scientists have an obstacle, though. Often, the reporters covering “alien” stories don’t understand the science themselves. Or the science is too new to come up with any definite conclusions. But if you start out by reading about an “alien megastructure” in space (a real-life story from last year), then scientists find out that the weird pattern of dimmings and brightenings was actually due to nothing more than dust, it is frustrating.
That’s where the Rio Scale comes in. First developed in 2001 and updated for the social media world just recently, the scale will help the public decide whether an “alien” story is actually credible. The scale ranges from “0” for “no evidence,” moves into the intermediate range around 5, and then ranks stories with the most extraordinary evidence at 10. Scientists can publish or tweet the Rio Scale along with their findings, and hopefully, responsible journalists would do the same thing.
It may take some time for the scale to be widely used. The Rio Scale isn’t well-known today, even though it’s been in use for nearly 20 years. But perhaps some support from one of the most well-known SETI scientists will help to spread the word.
“The whole world knows about the Richter Scale for quantifying the severity of an earthquake; that number is reported immediately following a quake and subsequently refined as more data are consolidated,” said Jill Tarter, a co-author of the research and co-founder of the SETI Institute, in a statement.
“The SETI community is attempting to create a scale that can accompany reports of any claims of the detection of extraterrestrial intelligence and be refined over time as more data become available. This scale should convey both the significance and credibility of the claimed detection.”
Lead researcher Duncan Forgan, who is with the Centre for Exoplanet Science at the University of St. Andrews, added in the same statement that the general public will better understand science research with the scale. “[It] helps us keep their trust in a world filled with fake news,” he said in the same statement.
Do you agree with their conclusions? Check out more details about the updated Rio Scale at the International Journal of Astrobiology, and let us know what you think. You can also use this (older) handy online calculator for Rio, which surely will be updated soon with the newest scale.