Fuzzy logic? What's the term for this method of argumentation.

August 29, 2010 11:31 AM

Is there a term for back-arguing a conclusion? I can't even find the proper words to describe the method of argumentation I'm thinking of, but I'll do my best. Someone comes to a conclusion. They then search for a justification to reach that end, working backwards and incorrectly. Here's a real life example:

A) Indie movie theater closes. B) Someone smugly argues that theater closed because there's no market for indie films in the town.

However, the real reason there's no market for indie films in the town is because the indie theaters keep getting closed. So A led to B, not B --> A.

Does this make any sense at all? Is there a term for this kind of false justification?

posted by Brittanie to writing & language (29 answers total)

Working backwards is what I always call it.
posted by Slinga at 11:32 AM on August 29, 2010

This sounds like a variation of affirming the consequent. In this type of logical fallacy, if x produces y, then x is assumed to always precede y, even if y may be caused by other factors. To use your example, if there is no market for indie films (x), then indie theaters will close (y). The smug person in your example is assuming that indie theaters have closed (y) because there is no market for indie films (x). In fact, other factors may have caused the theater to close.
posted by pecanpies at 11:45 AM on August 29, 2010 [3 favorites]

Your example is similar to the the correlation-implies-causation fallacy. I don't think it's quite what you're looking for though.
posted by chrisamiller at 11:45 AM on August 29, 2010

Post hoc ergo propter hoc also seems related.
posted by tss at 11:47 AM on August 29, 2010 [1 favorite]

And, of course, affirming the consequent is jut a form of an if-then fallacy.
posted by pecanpies at 11:48 AM on August 29, 2010

Hindsight bias ("I saw it coming")

Or perhaps good old "Correlation does not imply causation", from Wikipedia:

The cum hoc ergo propter hoc logical fallacy can be expressed as follows:

1. A occurs in correlation with B.
2. Therefore, A causes B.

In this type of logical fallacy, one makes a premature conclusion about causality after observing only a correlation between two or more factors. Generally, if one factor (A) is observed to only be correlated with another factor (B), it is sometimes taken for granted that A is causing B even when no evidence supports this. This is a logical fallacy because there are at least five possibilities:

1. A may be the cause of B.
2. B may be the cause of A.
3. some unknown third factor C may actually be the cause of both A and B.
4. there may be a combination of the above three relationships. For example, B may be the cause of A at the same time as A is the cause of B (contradicting that the only relationship between A and B is that A causes B). This describes a self-reinforcing system.
5. the "relationship" is a coincidence or so complex or indirect that it is more effectively called a coincidence (i.e. two events occurring at the same time that have no direct relationship to each other besides the fact that they are occurring at the same time). A larger sample size helps to reduce the chance of a coincidence, unless there is a systematic error in the experiment.

In other words, there can be no conclusion made regarding the existence or the direction of a cause and effect relationship only from the fact that A and B are correlated. Determining whether there is an actual cause and effect relationship requires further investigation, even when the relationship between A and B is statistically significant, a large effect size is observed, or a large part of the variance is explained.

posted by the young rope-rider at 11:48 AM on August 29, 2010

Errr, just. Old keyboard!
posted by pecanpies at 11:49 AM on August 29, 2010

Specifically, logical non sequitur.

Generally, peruse this.

Enjoy.
posted by coffeefilter at 11:52 AM on August 29, 2010

If they're actually, literally arguing that B --> A, that the cause is dependent upon the consequence, that sounds like a form of teleological argument.

But if it's a disagreement as to whether A is a cause and B is a consequence of A or B is a cause and A is a consequence of B, it doesn't seem to me that there's strictly anything wrong with their method, it's just that they've reached an erroneous conclusion by not taking some facts into account I guess. Scientifically you would say that A and B are correlated (assuming that the data really does support this) and you'd be very circumspect and tentative about saying whether or not one caused the other.
posted by XMLicious at 11:56 AM on August 29, 2010

I would call it Becking the question, but that's just me.
posted by scody at 12:00 PM on August 29, 2010 [5 favorites]

It's not far off begging the question
posted by genesta at 12:02 PM on August 29, 2010

retrospective rationalization
posted by found missing at 12:03 PM on August 29, 2010

Is there a term for this kind of false justification?

I don't think it is, in fact, a false justification. It seems to be a circular cause and consequence.

Indie theaters closing cause there to be no market for indie films in town which has the consequence of indie theaters in town closing.
posted by doomtop at 12:06 PM on August 29, 2010

O.P., can you clarify why you believe your friend is mistaken?

It seems to me highly plausible that an indie cinema would close because it fails to find a large enough market (though of course there may be other causes in play). I don't see why you are so convinced that this lack of demand played no part in the cinema's demise or that it is some kind of prima facie logical error.
posted by dontjumplarry at 12:14 PM on August 29, 2010 [2 favorites]

Also, I think what the smug person's argument is called depends on whether or not the smug person is aware that there is no market for indie films in town because indie film theaters in town keep getting closed.
posted by doomtop at 12:18 PM on August 29, 2010

One could mischievously call it "scholarship", thereby using the same technique. My conclusion would in this case be: some scholars typically use a collection of data, selection of historical information or some other hand-picked documentary material to confirm their pet theories or to tell their pet narratives in their pet way. Pet theory, in this technique, comes first, collecting the support later. Unwelcome material is suppressed.
My manner of arguing myself back toward proving this claim would be to hand-pick some examples of this technique, and to say, "since they call themselves scholars, it is hereby proven that scholarship is bogus".

But seriously. The basic principle you describe is indeed what I just wrote: to put one's pet theory in place and then to collect material to prove it right. It is a matter of principle, then, that your 'proof' is based on selectivity. The 'backwards' element, as well as the correlation and cause issues, are all only various principles of choosing one's support material, which just as well could be completely random. So the term you in fact are looking for is, no joke, "bad research".

And indeed: your friend may just as well be right. Your claim that the movie theater story unfolded the other way round is also selective. It disregards the hardest nut for sociologists or economists of modern culture (add favorite other branch) to crack: interactivity, and macro-micro shifts of perspective.
posted by Namlit at 12:26 PM on August 29, 2010 [1 favorite]

As Namlit describes, there's the term "cherry-picking", which refers to the process of selecting data especially supportive of the hypothesis while ignoring data that is unsupportive or contradictory.
posted by XMLicious at 12:49 PM on August 29, 2010

Maybe 'rationalization?' That's where you decide what the answer is out of your ass with no data, then find or make up a bunch of anecdotes that agree with you. It's very effective when you're trying to talk yourself into a conclusion you want to be right.
posted by ctmf at 1:18 PM on August 29, 2010

I would call this "reverse justification", which is a phrase nobody has mentioned before.

I have to agree with nojumplarry, it seems perfectly logical to me that there's no market for indie films in that town, or at least, no market for the experience of seeing them in a cinema. The town might be turning over a million dollars a year in indie films rented from Netflix and watched on DVD.

His or her conclusion would seem to be the Ockham's Razor explanation, i.e. the simplest one which fits the facts. If there are more facts, like the price of running a cinema going up, or the price of obtaining indie films from distributors, then there may be other explanations.
posted by AmbroseChapel at 1:33 PM on August 29, 2010

Confirmation Bias is similar (for the sake of completeness), though this seems closer to affirming the consequent.
posted by gregglind at 1:40 PM on August 29, 2010

I don't even understand why you think your friend's argument is bad, so it's hard for me to come up with a term for the supposed error.

"Indie movies aren't popular in this town" seems like a very plausible explanation for "the indie movie theatre in this town went out of business." In fact, you can spell out the logic:

1. If indie movies are very popular in this town, you won't see a pattern of indie movie theatres always closing in this town. (This is kind of like saying: If iPods are very popular in the United States, you won't see a pattern of lots of stores throughout the United States discontinuing their iPod inventories.)

2. Indie movie theatres keep closing in this town.

3. Therefore, indie movies are not very popular in this town.

That's not an airtight argument: premise 1 is too certain in assuming that indie movies couldn't be popular without indie movie theatres being popular (there are other formats for watching movies). But you can still see the basic logic to the argument.

You seem to think that of course the causation went the other way and only the other way: The movie theatre closed. Consequently, indie movies became less popular. OK, that's a plausible theory on its own.

But why did the movie theatre close?
posted by jejune at 2:53 PM on August 29, 2010

Is it inductive reasoning vs deductive reasoning?
posted by ThatCanadianGirl at 3:09 PM on August 29, 2010

It's hard to tell exactly what sort of fallacy you're looking for, given that in your example your smug friend is right. I think you're equivocating on (A). If (A) says that some particular movie theater closed (let's call it the Rialto), then it's very possible that the lack of a market caused the Rialto to close. But if you and your smug friend are having this conversation right after the Rialto closed, then the closing of the Rialto isn't what caused the lack of a market... after all, it only just shut down. If, on the other hand, (A) says that "many indie theaters have shut down", then it could be the case that (A) caused (B). And that, in turn, could have caused the Rialto to close... the other interpretation of (A).

I can't tell exactly what features of your friend's reasoning you are objecting to. It's not in general epistemically irresponsible to posit a conclusion and then hunt about for evidence or an explanation... that's just hypothesis testing. There's nothing wrong with working "backwards," but it sounds like you're objecting to a particular sort of mistake made when reasoning backwards. Is it relevant that you and your friend are engaging in reasoning about causation?
posted by painquale at 3:13 PM on August 29, 2010

N-thing those who question whether this is really a logical fallacy. Logical fallacies are usually statements along the lines of

"If A implies B, then B implies A"
or
"If A implies B, then A implies C" --

in short, they are assertions about supposed relationships between propositions, rather than propositions themselves.

Your disagreement with the smug person instead takes the form

"A implies B."
"Wrong: B implies A."

I would call this a disagreement about causality; from what you have given us, neither of you can be shown to have made an outright logical error.
posted by foursentences at 3:49 PM on August 29, 2010 [1 favorite]

There are two possible scenarios in which the smug person is not innocently disagreeing with you.

1) The smug person knows that they are making a bad argument (i.e. they know that their reasoning is unsound) but pursues the argument anyway.

2) The smug person is arguing simply to win the argument (and thus putatively prove their conclusion correct) without regard to what is actually the truth of the matter.

In either case the smug person is engaging in sophistry.
posted by oddman at 6:54 PM on August 29, 2010

The Bottom Line addresses this, although it's not precisely a name.
posted by novalis_dt at 6:54 PM on August 29, 2010

The problem here is that you haven't given us an example of what you described.
posted by thesmophoron at 10:11 PM on August 29, 2010

Its just "bad science". Good Science comes from finding data, and drawing a conclusion from that. Bad science is finding data that is only relevant to backing up the hypothesis.
posted by hal_c_on at 7:02 AM on August 30, 2010

I call this post-hoc rationalisation.
posted by Happy Dave at 8:33 AM on September 6, 2010