

Thou Shalt Not Commit Logical Fallacies [poster] - jonah
http://www.yourlogicalfallacyis.com/poster

======
eeeeaaii
I have to say this.

I was getting annoyed at the oversimplified, vague, and/or unclear
explanations on the poster. It's great to have a poster cataloging logical
fallacies, but it's not so great if it doesn't actually explain them very
well.

So I go to the home page of the site, where the first sentence reads:

"A logical fallacy is usually what has happened when someone is wrong about
something."

FACEPALM.

The validity of a logical argument has NOTHING to do with the actual veracity
(rightness or wrongness) of the propositions. This is basic stuff. Logic is
the process of figure out what other things we know based on what we already
know. If what we think we know is wrong, then we can make all the logically
correct arguments we want and we'll still be drawing wrong conclusions.

~~~
bunderbunder
And, on the other side of the coin, I fear it encourages folks to fall victim
to the 'fallacy fallacy': Thinking that the presence of a logical fallacy in
an argument implies that its thesis is incorrect.

On a completely different coin, nobody ever won an argument by treating it as
a game of Spot the Logical Fallacy. All you'll win playing that game is a
reputation for being insufferable.

~~~
repsilat
> the 'fallacy fallacy': Thinking that the presence of a logical fallacy in an
> argument implies that its thesis is incorrect.

It's worse than that. Paying too much attention to rigour and the mathematical
validity of arguments unduly privileges strict logical argumentation over
"traditional" informal argumentation.

Outside of technical areas there are almost no arguments amenable to pure
logical argumentation. Think about it - why would you be arguing over
something that can be mechanically deduced with certainty? In most
circumstances logical syllogisms and the like are used only as "glue" to hold
the _real_ argument together.

We should recognise that arguments using these "fallacies" don't have absolute
persuasive power, but we shouldn't go so far as to say that they can have no
persuasive power at all.

~~~
jiggy2011
I think pointing out a fallacy can sometimes be a good defense against
somebody who is insisting that something is a mechanical certainty when it is
not.

~~~
bunderbunder
Yes. But more often's the case that the fearless fallacy hunter fallaciously
finds fallibility by fantasizing formality or finality.

Thereby committing a fallacy himself in the form of a straw man.

~~~
jiggy2011
I see what you did there , I think I'm going to use that.

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Locke1689
A lot of these are wrong. Examples:

 _Slippery slope -- Asserting that if we allow A to happen, then Z will
consequently happen too, therefore A should not happen._

Slippery slope is not necessarily a fallacy -- it is only a fallacy if the
warrant is extreme. If we were arguing about dropping lit cigarette butts into
the trash and we both agreed that fires were bad and I made the claim that we
shouldn't drop cigarettes in the trash because they often cause fires (and
cited data to that effect) there would be no fallacy in my argument.

 _Appeal to authority -- Using the opinion or position of an authority figure,
or institution of authority, in place of an actual argument._

This one actually infuriates me because it may be the most wrongly used
logical fallacy. First, because most people who use this argument are _not_
making a logical deduction, they're making a statistical argument. To cite
from Wikipedia:

 _The appeal to authority may take several forms. As a statistical syllogism,
it will have the following basic structure:[1] Most of what authority a has to
say on subject matter S is correct. a says p about S. Therefore, p is correct.
The strength of this argument depends upon two factors:[1][2] The authority is
a legitimate expert on the subject. A consensus exists among legitimate
experts on the matter under discussion._

There is nothing wrong with this argument. The example given in the poster is
very bad. As a PL student I have a bit of experience with formal methods and
I'll remind everyone that the only things which can be _proven_ using logic
are those which follow directly from the definitions. In real arguments, these
structures basically never exist. The truth never follows _necessarily_ from
the things people say, it's almost always a statistical argument. The fact
that medical authorities used to think wrong things about the body didn't
necessarily mean that it is or was wrong to believe in the body of scientific
knowledge at the time. It only means that you have to be aware of the error
margin in your statistics.

~~~
olalonde
Have you read the longer descriptions?

<http://www.yourlogicalfallacyis.com/appeal-to-authority>

<http://www.yourlogicalfallacyis.com/slippery-slope>

Your concerns seem to be addressed there.

~~~
Locke1689
First, those links address my points improperly, if at all. Slippery slope
once again assumes that the warrant is extreme but there is no such guarantee
in the construction presented.

Second, even if the extra links on the site were correct I don't see why that
would make the poster itself any less wrong.

~~~
olalonde
From the description: "[...] shifts attention to _extreme_ hypotheticals
[...]" (also present in the A1 poster)

In any case, I see this poster as a cheat sheet: not something to learn from,
but a quick reference for someone who has already done their homework and
learned about those logical fallacies.

~~~
Locke1689
The problem is that I can't see how this is correct, even to the trained eye:

 _Argument from authority -- It is important to note with this fallacy that
authorities in given fields may very well have valid arguments, and that one
should not dismiss another's experience and expertise. To form an argument,
however, one must defend it on its merits i.e. know why the person in
authority holds the particular position that they do._

Only vaguely. You don't actually have to know what general relativity is or
how it works to form an argument based on the statistical likelihood of
physicists being correct. You don't really have to know "why" the person in
authority holds their opinion, only that they are both an expert on the topic
they are covering and that there is a general consensus among other experts on
the same topic.

 _It is, of course, entirely possible that the opinion of a person or
institution of authority is wrong; therefore the authority that such a person
or institution holds does not have any intrinsic bearing upon whether their
claims are true or not._

I'm not sure what this is trying to say, but there's certainly justifiable
basis in believing that person's authority has an intrinsic bearing on the
_probability_ that their claim is true.

How is the quoted definition at all useful -- to either logicians or laymen?

~~~
azundo
Perhaps suggest an alternative to be put on the poster? Seems like this is a
project about education and not about proving expertise in logical fallacies.
I would expect that the authors would be welcoming of increased clarity and
correctness in their examples.

~~~
Locke1689
I tend to like this site: <http://www.fallacyfiles.org/introtof.html>

------
jiggy2011
The only thing more annoying than people who regularly commit logical
fallacies are teenagers who argue on the Internet having just read the
wikipedia page on logical fallacies.

For example: "the british medical association has said that smoking increases
risk of cancer" therefor it is best not to smoke.

At which point you will get "Aha! You just committed appeal to authority and a
slippery slope fallacy, you must be wrong!".

I suppose this is partly because in real life arguments we very rarely have
sufficient knowledge in any subject to make concrete formal arguments based on
direct observations, we are usually discussing the likelyhood of different
things being true.

~~~
instakill
Reddit has come to love the reference to the straw man fallacy of late.

------
jeremysalwen
It's incredibly ironic that this poster features Plato, Socrates, and
Aristotle. They all commit ALL of these fallacies with regularity, with the
exception perhaps of the Texas Sharpshooter, because in order to commit that
one, you actually have to appeal to _data_.

“Aristotle maintained that women have fewer teeth than men; although he was
twice married, it never occurred to him to verify this statement by examining
his wives' mouths.” ― Bertrand Russell, The Impact of Science on Society

~~~
morsch
How is that a logical fallacy? That's just a lack of data and an unwillingness
to gather it.

~~~
jeremysalwen
Oh, certainly, that wasn't the point of the quote. I was just pointing out how
supremely stupid these guys were, for everything they gave us. But it probably
falls lightly under burden of proof.

There's a quote which I thought was from a friend of mine, but when I asked
him, he denies ever saying it, so I'm not sure where it's from: "Philosophy is
the history of bad arguments." I just quoted Russel, because he's a bit more
of a respected authority on the subject.

------
Cogito
Though Shall Not Propagate Common Myths: from 'bandwagon' - "The ﬂaw in this
argument is that the popularity of an idea has absolutely no bearing on its
validity. If it did, then the Earth would have made itself ﬂat for most of
history to accommodate people’s popular belief."

While 'most of history' is a long time, the knowledge of a round earth has
been around (and popular) since around 300 BC. It may be true that humans, and
even that written (let alone verbal) histories, have been around for much more
than 2000 years, the commonness of this myth warrants a different example. You
wouldn't want to be seen supporting a position that only exists because many
people think it is true, now would you :D

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ekianjo
It's not perfect but the icons are pretty well done. I imagine they could be
used to "flag" posts, to let people know when they commit fallacies.

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alttag
... would be nice if I could read the poster. "Account has been suspended"
error message.

Sometime after I loaded the landing page but before I could click a link, the
account/site went "poof".

~~~
jonah
Back up, but if it goes down again here's a cached copy:
[http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...](http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_A1.pdf)

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rollypolly
HN could use a cheat-sheet version of this above the comment box. ;)

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jarin
If anyone wants it without having to go to the print shop, it's up on Zazzle:
[http://www.zazzle.com/thou_shalt_not_commit_logical_fallacie...](http://www.zazzle.com/thou_shalt_not_commit_logical_fallacies_poster-228887783776402214)

You can also add it to Zazzle yourself and get it for a little cheaper, just
make sure you put in the right dimensions, i.e. A2 (594x420mm or 23.4 x 16.5
inches) or A1 (841x594mm or 33.1 x 23.4 inches)

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dustyreagan
Great poster, but instead of donation button, you should have a "buy a print"
button.

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pepve
Hmm, I'm guilty of most of these.

So now I think they are heuristics rather than absolute measurements. And we
should use them to teach ourselves something about logic, but not others.

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JoeAltmaier
Great salesmanship tool worksheet!

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SneakyBeak
Site is down.

~~~
jonah
Copy here:
[http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...](http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_A1.pdf)

