Does (Fallacious) Induction Have Enthymemes?

argument-enthymeme-fallacy

I’ve been trying to figure out what precise kind of fallacy is the line that runs “Hitler wore pants, you wear pants, therefore you’re like Hitler.” It’s not a reductio, which would be closer to “Hitler wore pants, therefore wearing pants is bad.” It kind of looks a lot like a false analogy – hat tip to Zoltan Majdik for pointing that out – but if it is, it’s in a weird form. GT Goodnight suggested it’s a fallacious syllogism that’s been rendered enthymematically, where the problem is that the middle wasn’t distributed correctly. That seems close too, but the statement does bear an awful strong familial resemblance to false analogy, which would put it on the side of induction.

What it actually looks like is a fallacious induction that’s been rendered “enthymematically,” where the specific (informal) fallacy is that it’s a false analogy. So two more questions to hash out in the comments, in addition to figuring out what statement technically is: (1) is there a name for the inductive equivalent of an enthymeme, where steps are suppressed for rhetorical purposes, and (2) is there a taxonomy of specific inductive fallacies that’s more detailed than the usual hasty generalization, unrepresentative sample, false analogy, slothful induction, and fallacy of exclusion?

In a standard false analogy we (tenably) reason that Y is like X because Y shares certain (presumably salient) properties with X. But then we add the (informal) fallacy of insisting that therefore Y has a specific negative property which is actually unique to X:

X has properties {P1…Pn} of which one is Q
Y has at least one property {P1…Pn}
Therefore Y is like X
Therefore Y has property Q

To get back to the Hitler line, that would roughly be:

X (Hitler) has P (wears pants) and Q (is really bad guy)
Y (you) has P (pants)
Therefore Y (you) is like X (Hitler)
Therefore Y (you) has Q (is really bad guy)

But the statement is very importantly not that, which is rhetorically critical. Once you make Q explicit – once you enunciate the stuff about being a really bad guy – the reasoning becomes obviously fallacious. So instead any mention of Q is totally suppressed, both in relation to X and in relation to Y, and we have:

X has P
Y has P
Therefore Y is like X

That’s the form of “Hitler wore pants, you wear pants, therefore you’re like Hitler.” Again this is doubly weird because we’re dealing with an induction that’s fallacious. So even if there was a taxonomy of inductive enthymemes that symmetrically mirrored the standard enthymemes, we wouldn’t get that here because the fallacy is screwing up the symmetry.

In fact just by suppressing Q we already get three different rhetorical versions:

[A] Q’s relation to both X and Y is suppressed (that’s the one we just did, which matches “Hitler wore pants, you wear pants, therefore you’re like Hitler”):

X has P
Y has P
Therefore Y is like X

[B] Q’s relation to X is suppressed, but Y having Q is explicitly stated:

X has P
Y has P
Therefore Y is like X
Therefore Y has Q

[C] Q’s relation to Y is suppressed, but X having Q is explicitly stated:

X has P and Q
Y has P
Therefore Y is like X

There are obviously more elements to suppress which would create more combinations. You can rhetorically skip the statement “therefore Y is like X” and jump directly to “therefore Y has Q,” for instance.

But the questions are: (1) is “Hitler wore pants, you wear pants, therefore you’re like Hitler” bad induction or bad deduction, (2) what kind of bad induction or deduction is it, (3) does anyone have a detailed taxonomy of fallacious inductions?

References:
* zoltanmajdik [Twitter]
* goodnight [Twitter]
* Fallacy of the undistributed middle [Wikipedia]
* Inductive Fallacies [One Good Move]

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* Classical Rhetoric
* Argumentation
* Rhetoric and Philosophy

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