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Evaluating a source’s reasoning and evidence

Don’t believe everything you read! A source has to give you a reason to trust it before you can accept what it’s trying to tell you. You can’t just accept it on faith when someone tells you there are goblins on the moon. How do they know that, and how can they prove to you that it’s true? (They can’t!) But you need to learn to trust SOME sources, or you won't be able to do everyday tasks without an overwhelming sense of doubt. So let's figure out how to evaluate sources. Created by David Rheinstrom.

Video transcript

- [David] Hello, readers. How do we know what is true, and what isn't? My mama always told me, "Don't believe everything you read. "Just because someone took the time to write something down, "send it off to be typeset and designed "and printed in a book or published on the internet, "doesn't mean they bothered to tell you the truth." You should be skeptical of all informational writing until the writer gives you a reason to trust them. Honestly, you should be skeptical of me until I give you a reason to trust me. Who am I, after all? Just some stranger on the internet. Well, that's a little unfair, actually. You probably knew about Khan Academy well before you watched this video, which means you have a sense that the information we teach is reputable or trustworthy. So, maybe I'm already at an advantage for you trustworthinesswise, because you associate me with an institution you already have good feelings about. When an author writes for informational purposes, they want you to believe that they're telling the truth, but you can't just accept that on faith. No human being is so important that they can't be bothered to explain themselves. Now, let's be clear, that doesn't mean that everyone you disagree with personally owes you an explanation. It just means that you don't have to swallow their arguments hook, line, and sinker. So, how do we move forward? We can't just go around in a nightmarish swirl of misinformation, never knowing whom to trust. That's no good. Society couldn't function. Imagine looking at the weather report and saying, "I don't believe you!" And then, walking outside your home in shorts when the forecast calls for snow. That would be terrible, for you. The key is to ask yourself, "Why should you trust the weather forecast?" Well, forecasters are scientists, specifically meteorologists. Their job is to study weather patterns and make predictions. And that doesn't mean they always get it right, because they're making what amounts to educated guesses about the weather. But their expertise and their access to weather monitoring equipment make them likelier to know what the weather's going to do than the average person would. And this is basically the test you should bring to all informational writing. Good readers look for clues to establish trustworthiness, to establish that the author knows what they're talking about, that they've done the research, that they're an expert worth listening to. Someone who hops on YouTube and says, "Here's why your teachers are lying to you "about the goblins who live in the moon," is someone that warrants some skepticism, a little side-eye. Also, how awesome would it be if there were moon goblins? And why would anyone want that information to be kept secret? Okay, when you look at a text, you have to wrap your head around three big things. One, the main idea or the claim. What is the author trying to say, explain or convince you of? Two, the evidence for that claim? What are the facts, details, or other pieces of information that tell us that that claim is true or accurate? And three, the reasoning. How the evidence prove that the claim is true? Okay, so let's imagine that this conspiracy guy on YouTube is trying to make the case about those goblins. Let's listen in on his argument. - [YouTuber] I firmly believe that there is a colony of goblins living inside the moon and the government is keeping this information from you. How do we know this? Look at the moon! See that little squiggle? You were taught that was just a crater, but it isn't! It's actually the tip of an enormous goblin moon base. How do I know that? The goblins told me so. I have a special phone line from my house to the moon goblins. And through me, they can answer any questions you've got. Our moon door is always open, the goblins tell me. - [David] All right, so, what's the claim? Goblins live inside the moon. What's his proof? What we think is a crater on the moon is actually a goblin moon base. What's his reasoning? What backs that up? He says the goblins told him so. Now, is that evidence? Or is that just something he's telling us? Well, one way we can know he's probably full of baloney is that only he can talk to the moon goblins. Right, he says he's got a special phone line. They can answer questions through him. We can't talk to the goblins. We can't have access to any of their information. He's behaving like the information is freely out there for anyone, but it isn't. You have to go through him. So, can the stuff he's saying be independently verified? That is to say, can anyone other than this person prove that there are moon goblins or that that crater is a moon base? Are there photos or video from those goblins? And if not, why not? This doesn't pass the smell test for me. There's proof, but only I get to see it, is not proof. That's just made up. When it comes to making arguments, you have to show your work. A good writer has to earn the trust of their audience. And a good reader has to make a writer work for that trust. "What does that look like?" I hear you asking. Excellent question. Let's take a look at a piece that does its homework. Okay, let's read. "There are some conspiracy theorists "that claim that NASA's moon landing missions "in the late 60s and 70s never happened, "despite the mountain of evidence to the contrary. "They claim that the photographs were faked, "the mission recordings were scripted, "and the moon rocks were nothing more "than ordinary earth rocks. "Perhaps you are among these conspiracists. "If so, let me prove to you "that the moon landings took place. "Perhaps you are skeptical of the US government, "which was in the middle of the Cold War "with the Soviet Union and a shooting war in Vietnam. "Perhaps you believe that any information from NASA "is therefore suspicious. "Fortunately for you, "there is plenty of third-party evidence "that Americans traveled to and landed on the moon. "An observatory in the UK that previously observed "the Russian launch of the Sputnik probe "used its radio telescope "to observe the 1969 moon landing. "The Bochum Observatory, this one in Germany, "also confirms that mission. "Finally, present-day photos "from many different space agencies around the world "have confirmed the presence of footprints, rover tracks, "and the lunar rovers themselves. "In order for a moon landing to have been faked, "the rocket scientist James Michael Longuski "estimates that more than 400,000 people "who worked on the projects in some capacity "would have had to keep the conspiracy a secret. "In his 2006 book 'The Seven Secrets of How to Think Like a Rocket Scientist,' "Longuski suggests that given how complicated it would be "to fake such a project, "it might actually be easier to just go ahead "and do the moon landing in the first place." So, if you don't believe the US government, this writer is saying, let's look at some other sources. How do we know those sources are real? Well, we have some names to look into to independently verify it. We've got this rocket scientist. We have the name of this German observatory. We could look into and verify these statements. It's not just one guy asserting that there's goblins on the moon. It's someone saying here are some non-NASA sources that can confirm that Americans landed on the moon. Be careful out there. It's a wild world of people who wanna bend your brains and turn you against your neighbors. Use your brain, your heart, and your reading skills to fend them off, as you develop your principles. You've got this, readers. You can learn anything. David out.