[Informatics] Logical fallacies and other bad stuff when evaluating secondary information

Fri Mar 25 20:29:43 AEDT 2016

Thank you Laurie, that cartoon is another nice illustration that "Correlation does not imply Causation”. In other words, a correlation between two variables does not imply that one causes the other. Students need to watch out for this trap, especially how they word any discussion and conclusion.
	http://www.abs.gov.au/websitedbs/a3121120.nsf/home/statistical+language+-+correlation+and+causation
	https://en.wikipedia.org/wiki/Correlation_does_not_imply_causation

Whilst it is an often abused type of evidence, correlation has a place in data analytics and science. The tobacco industry has historically relied on a dismissal of correlational evidence to reject a link between tobacco and lung cancer. When you discover a positive correlation for the first time, you need to go down the rabbit hole of systematically exploring all the different possible causative relationships.

Here is a link to my slideshow that explains this further. Feedback welcome :-)
https://www.evernote.com/l/AB_JOY7brAJDQZb9KGB4U6N1clVw6vuISDE

Regards Roland

> On 22 Mar 2016, at 4:48 PM, Laurie Savage <08327998 at pvgc.vic.edu.au> wrote:
> 
> Of course it's well known that brain cancer causes mobile phone demand. 
> 
> http://xkcd.com/925/ <http://xkcd.com/925/>
> 
> Laurie
> 
> 
>> On 22 Mar 2016, at 4:16 PM, Mark <mark at vceit.com <mailto:mark at vceit.com>> wrote:
>> 
>> Hi fellow fallacious folk 
>> 
>> During your kids' incursion into hypothesis formulation and evaluation of secondary sources, there are some logical fallacies and bad practices you might want to point to. 
>> 
>> - Causation - If A and B are correlated it does not mean A causes B. 
>> Or B might cause A. 
>> Or A might cause B while B also causes A in a feedback loop. 
>> Or both A and B might be caused by unknown factor C.
>> Or similarities between the trends in A and B may be purely coincidental.
>> 
>> - Just because A happens before B does not mean A causes B. This is a particularly dangerous fallacy, e.g. immunization causes autism; a cancer sufferer drank green tea and had complete remission, therefore green tea cure cancer.
>> 
>> - Confusion of cause and effect - "He's unmarried because he's so angry" vs "He's so angry because he's unmarried".
>> 
>> - A series of random events (e.g. coin tosses) that show a pattern are not actually causally linked.
>> 
>> - Cherry picking - selecting only the data that supports a hypothesis.
>> 
>> - Ignoring extraneous variables - Assuming that only one possible cause exists when in fact others are possible.
>> 
>> - Ad hominem - attacking the person on irrelevant personal grounds rather than attacking his or her argument. e.g. "Could you believe a tattooed and pierced freak like him could ever be a serious member of parliament?"
>> 
>> - Using loaded questions - questions that have inbuilt assumptions, e.g. "Considering the growing rates of autism, would you have your child immunized?"
>> 
>> - Using leading questions - that contain information that suggests the desired answer. e.g. "As a responsible parent, would you risk immunizing your child?"
>> 
>> - Double-barrelled questions - which lead to ambiguous results by combining two separate variables, e.g. "Do you agree with child immunization and circumcision? Yes/No."
>> 
>> - Questions that force some people into giving inaccurate answers, e.g. "Do you go to church daily / weekly / occasionally." The options are incomplete.
>> 
>> - Vague, ambiguous or subjective questions - that may be interpreted differently by different people. e.g. "Are men superior to women?" (in what respects?) or "Do you swear often?" (what does "often" mean?)
>> 
>> - Begging the question - assuming the truth of an issue that is in question. e.g. "But he's a gentle, law-abiding man! How could he possibly be guilty of this horrific massacre?"  (It annoys me mightily when people say this when they actually mean "raises the question". e.g. "He said he was a lazy man, which begs [raises] the question of how he achieved so much.")
>> 
>> - Over-generalisation - extrapolating from small number of observations to formulate a rule, e.g. "The Collingwood fans I saw at the pub after the match were rowdy, annoying, drunken idiots. I hope my daughter never has to live in Collingwood."
>> 
>> - Misusing anecdotal evidence - single or personal examples do not over-ride large masses of contrary evidence. e.g. "Feisty Edith is still full of vim and vigour at the ripe old age of 100 and she still smokes a cigar every day! Smoking obviously can't be too dangerous, can it? Ha ha ha. Over to you for tips on how to cook kale and quinoa pizzas, Sandra. Ha ha ha."
>> 
>> - Appeal to emotion - side-stepping logic by using emotionally-charged claims. e.g. "You shouldn't immunize your child. Think of the tragic and devastating life-long effects this can have."
>> 
>> - Appeal to pity or fear - e.g. "An immunized child, stricken with autism, doomed to live a life of pain and suffering and <insert horrors here>. How can you let this happen?"
>> 
>> - Unproven compromises - a weak attempt to play it safe by pleasing everyone a little bit. e.g. "Some people believe that immunizations cause autism. Some believe they don't. Let's just say than that some immunizations cause autism, OK?"
>> 
>> - Burden of proof - avoiding giving substantiating evidence by challenging the opponent to prove otherwise. e.g. "I am sure immunization causes autism. Show me one piece of evidence that I'm wrong."
>> 
>> - Appeal to ignorance - assuming that something must be true (or false) just because it has not 
>> been proven false (or true). e.g. "Ghosts exist. No-one has proven they don't!" (this is similar to  'burden of proof' above)
>> 
>> - Wrongful dismissal - reasoning that because an argument was poorly presented or had spelling mistakes, then it must be wrong. This is common amongst Spelling Stormtroopers on forums, e.g. "You can't even spell 'their' properly. How can we believe you when you say rubbish like 'Jon Snow is going to come back from the dead in season 6?' ROFL. Buy a dictionary, Hodor."
>>   
>> - Appeal to tradition - arguing that an idea must be wrong because "We've never been done it that way" . Or saying that an idea is right because it's commonly practised. "Hundreds of lobotomies are performed every day, Mrs Smith. I really don't know what you're so worried about."
>> 
>> - Sheer ignorance - belief that a hypothesis must be wrong because one is too ignorant to understand it. "How can disease be caused by tiny germ things? Things can't be so small you can't see them? It's ridiculous." 
>> 
>> - Appeal to vanity - e.g. "Any intelligent reader will know that..."
>> 
>> - Reductio ad absurdum - exaggerating an opponent's argument to ridiculous extremes so it can be mocked. e.g. "These anti-immunization people say that the MMR vaccine causes autism. Next they'll be saying that aspirin causes your legs to fall off! How can you trust anything they say?"
>> 
>> - Appeal to novelty - assuming that something is better because it's new. e.g. 
>> "Windows Vista / 4K video / Microsoft Clippy / internet-connected fridges / 
>> voice recognition replacing the keyboard / the hydrogen-filled airship / The Atkins Diet" is new! Buy it now."
>> 
>> Bye
>> 
>> Mark
>> 
>> ---
>> 
>> Thanks to https://yourlogicalfallacyis.com/poster <https://yourlogicalfallacyis.com/poster> for some tasty input.
>> Also http://www.informationisbeautiful.net/visualizations/rhetological-fallacies/
>> 
>> By the way. The immunization/autism example I've used is just an example. 
>> But if you're morally outraged, please read this -  http://www.ncbi.nlm.nih.gov/pubmed/23545349
>> Do not email me about it. I validate and reject invalid input.
>> 
>> -- 
>> 
>> Mark Kelly
>> 
>> mark at vceit.com
>> http://vceit.com
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> 
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