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

[Mark]

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
<http://www.tylervigen.com/spurious-correlations>.

- 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 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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