How To Avoid Being Illogical
Here's a bit of good logic:
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The orange circle on the right contains .. probably we should say includes .. all mammals. That means rabbits and humans and lions and elephants. And many other creatures.
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And here's a bit of bad logic.
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The green circle on the left includes all elephants. The blue oval inside it includes all the Indian elephants. The part of the green circle outside the blue, then, includes all elephants which aren't Indian. Those would be the African elephants.
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In this issue of the Gnews we're going to look at all sorts of ways we can be misled by errors in logic. Many times as we wander along in life we'll hear arguments which seem reasonable at first glance, but which are in fact NOT reasonable.
"Bet those dogs up ahead will give us some ideas. Like, the three in front are talking? In English? It could be that dogs always get together when there's no human near, and have long conversations in the English language. About cats? And chasing cars? And who has the best master?"
I chimed in. "And how to get what you want. And where's the best place to bury bones."
Chloe agreed. "And who knows? Whether they're talking. They stop when any human might listen? So you can't prove that they're not talking? Why can't they be? That's the argument: We don't know, therefore it's true: dogs can speak English.
"The UFO believers make the same mistake," I added. "They see something in the sky. Nobody knows what it is. Therefore it's a traveler from outer space."
"It's, like, a perfectly logical argument. Except!! The first statement is of course, wrong," Chloe pointed out.
"Seems hard to believe that such logic could really be used," I continued." But it happens all the time. The problem is, we don't notice. So the government tells us, 'We’ve got to spend trillions of dollars to support banks, homeowners, and other failing institutions. Otherwise the country will suffer a terrible depression.'"
"The terrible depression is the white dog, and spending trillions is black," Chloe pointed out.
"But there are thousands of other choices," I went on. "Like doing nothing. Or spending billions instead of trillions. Or not supporting the banks... We could go on and on."
By this time we were wandering down a street and happened to notice that at the moment, all the cars we could see were blue.
I continued, "But foolish folks, seeing all blue cars like the ones all around us know, will figure the next car that comes by will also be blue.
Chloe agreed. "As if the car colors aren't random. But why shouldn't they be? Maybe there are 10 different car colors. If we assume any color is equally likely, then there's only one chance in ten the next car will be blue? Shouldn't bet on another blue. It's like a lady's been buying lottery tickets? And keeps losing? But she tells a friend she's going to take a trip to Europe. And her friend goes, 'How you gonna pay for it?' and the lady goes, 'I've been losing for years. I'm due for a win now.'"
"Good thing we're so smart," I bragged. "Never make mistakes like this."
"Hope not," Chloe replied, "but who knows? I've made mistakes. Just like everybody? A while ago I dated this blond guy? I thought he was really cool. And we had some buddies from the Italian part of town? And a couple of them were dealing in drugs? So then one day this blonde guy made it clear he though all Italians were dishonest. Just because of those few? And I gave him up. Just about concluded that all blonde guys are illogical?"
I laughed. "So he jumped to a conclusion about Italians, and you jumped to a conclusion about blonde guys."
"That's called 'Poisoning the Well," I said. "It started when there were terrible plagues in Europe in the 14th century. And it was said that certain people caused the sickness by poisoning all the wells. So you should shun those people. Your classmate told a story about you, and then warned the boy that he shouldn't trust you -- a conclusion that can't be drawn from what you told the blond boy."
"Right," Chloe replied. "But I figured out how to get even? I'd tell everyone that she was a girl never told the truth. So then what could she do? If she said she always was truthful, kids would just figure I was right? That she wasn't telling the truth? That'd poison her well!"
"Right," Chloe said, "and there's this argument? Says nobody has to wear a helmet when he's driving a car? So why a helmet law about, you know, bicycles? So that, like, leads to an argument why car drivers don't need helmets because they have seat belts?"
"And air bags," I agreed. "So you find yourself arguing about cars, when the real problem in bikes. That's a 'Red Herring'.... Wonder why they call a diversion a Red Herring?"
Chloe knew. "A red herring was one that is dried and smoked. Ready to be eaten? And if you dragged one across a fox's path, then the dogs chasing 'em would go off in the wrong direction? Here's another example. There's this chess club? At school? And we're talking about schemes to attract new members. But this one girl goes, 'We hardly have enough chess sets now, for all of us to play. Why do we want new members?' And so chess sets was the red herring. Got us off the subject of new members? And onto arguments about chess sets."
Chloe ignored my warning, and under the ladder she went. "And if tomorrow my dog disappears, it's because I walked under the ladder?"
"Right," I replied. "B follows A therefore B was caused by A. That's what the old Latin saying says. Post Hoc, Ergo Propter Hoc; 'after this, therefore because of this.' Probably they saw that logical error back in Julius Caesar's days. But it's still going on today. I have a friend says his computer broke down at work one week, and he lost his job the next week. Says it wasn't fair to lose a job because of your computer. But of course a dozen people lost their jobs that week at that company, all because business was slowing down. The computer had nothing to do with his problem."
I agreed. "A big building like that, all the classrooms must be big."
"Whoa, now," says Chloe. "That's, like, bad logic? Just because the building's big, you can't conclude all the rooms are big."
"Just checkin'," I said. "You're right. That's like saying 'My class is big, so all the kids in my class must be big.' Or 'The management of Company A cheated and lost a lot of money. Therefore all the people who work for that company are dishonest.'"
This Month's Puzzle
This issue's Gnarly Weather contains two fallacies. What are they?
What kind of fallacies are these?
1. The local Superintendent of Schools announces that the school budget has been cut, and he'll have to close the Jameson Elementary School.
2. You tell your mother that you've heard Clem's Uncle is a rogue, and she shouldn't believe anything he says.
3. Yesterday your best friend was seriously hurt in a car crash, and you decide you'll never ride in a car again.
(Continued from the bottom of the left column)
"Yep," Chloe said, "and everybody believes, you know, our soccer team will win the city championship this year."
"But we know that's bad logic," I remarked. "It isn't true just because everybody believes it. And what does 'everybody' mean? Everyone in the city? Of course not. Other schools think their teams will win."
"And even in our own school," Chloe added, "prob'ly there are some kids who don't believe. Who think the team's not all that good?"
"It's like the argument that 'everybody' believes CO2 is causing the earth to warm up. All sorts of scientists disagree with that. Be careful when you hear the words 'everybody believes', or 'everybody agrees'. Ask yourself, Who is Everybody?"
"I suppose most kids do. Maybe 2/3 or 3/4 them?"
"I'd guess 70%?" says Chloe. "But of course there's a place for a logical mistake."
"Right," I agreed. "Somebody might say from this sample that 70% of everybody in the US brings his or her lunch from home. But a sample in front of a school, where almost everyone who passes is a school-kid, is not exactly a fair sample of everybody in the US."
"It'd be like if you went '100% of the people think Congress is doing a wonderful job', "Chloe said. "But then somebody asked you what your sample was? And you said it was all the Senators and Representatives in Congress. Not a random sample."
I laughed. "Not a random sample."
"Baaaad," I agreed. "They're not talking about the songs. They're bringing Britney into the picture to change the subject. The fact that she sings them has nothing to do with whether they're good songs. She's like a figure made of straw, thought up to divert our attention from the songs themselves."
"So when the Governor goes, 'We must raise taxes to pay for improving bad roads in the state'. And someone argues? Going 'Higher taxes will hurt the poor, who hardly have enough money to buy food.' Hurting the poor is the Straw Man? Gets us talking about the poor, instead of the roads.
So I continued, "The average of 210 and 120 is 165. Therefore, that's what everyone should weigh."
"Same thing," Chloe added, "if your local mayor says the city council is a bunch of idiots? But the city council itself says it's perfectly sane. So do we conclude the council is full of half-wits? Being half way between sane and idiotic?"
We both laughed.
I laughed. "So it's evident that high school graduates are causing postage rates to increase!"
"So things are connected some way?" Chloe said. "Doesn't mean one causes the other. Our school football team won 6, lost 6 this year? And the girls' basketball team went undefeated. The football coach said he had a bad year because the whole student body was talking about the girls. So his 6 and 6 was caused by the girls' 13 and zero? No way!"
"That kind of thing happens," I said. "Something really striking happens, that everyone notices, and somehow it makes you forget what's normal. The unusual becomes something very likely to happen."
"Like when there's a really strong earthquake?" Chloe said. "In California? Lots of houses knocked down, and some folks hurt? And in the next year hundreds of people leave the state. Don't want to get caught up in one of those earth-shakers."
The Camel's Nose
"So when the city council wants to add another day to the school year, the kids naturally worry that a week will be added next year, a month the year after, and before long there won't be any vacation."
"It's, you know, like the old slippery slope?" Chloe said. "You get pushed over the edge just a little bit? And zoom, you're all the way to the bottom of the hill? Like, my father says, 'Don't buy that chocolate bar. Next thing you know you'll weigh 200 pounds!'"
"If we can't understand something" I said, "if it's really difficult for us to believe, then it can't possibly be true. Take Professor Einstein's theory that space is warped. One might say, 'That's crazy! If space was warped, my house, which is I hope in space, would be all twisted and bent. I wouldn't be able to open the front door. I simply don't believe it. Space is smooth.'"
Chloe agreed. "And there may be some folks who don't believe the Earth is round? They'd go, 'Don't be silly. If the Earth was round, the folks on the bottom side would fall right off; and those on the sides would have to cling to something to keep from dropping into space. Clearly the Earth is flat -- a sort of oval plate with all the continents sitting on it.' It's, like, hard to argue? Have to explain about Newton and gravity..."
"And another kid heard about that? He's sort of the class bully? And he goes, 'Don't pay any attention to that advice. Bill's father is town councilor, and you know all politicians are dishonest and disreputable.' So instead of talking about the advice, he attacks the advisor? Not logical at all."
"It's very like the ad hominem fallacy discussed elsewhere in this issue under School Days," I said. But the Personal attack is different because it's mean and hateful. For example, if a school Principal disciplines George for shouting in class, Bill might attack by telling his parents that the Principal hates all boys, and never disciplines girls."
Sam'll Answer 
