Is there a word for the logical fallacy of including a debatable proposition in a list of truisms?

Sometimes a salesman or a politician or whatever will toss out a string of statements that he knows the audience will agree with, so they're all nodding their heads and saying yes, of course. Then he tosses in a highly questionable statement. To make a deliberately oversimplified and silly example:

And as we all know, it's a good thing to love your mother. And I'm sure you all agree that chocolate tastes good. And we all know that all Ruritanians are stupid. And of course no one wants to get cancer ...

The idea is that you get the audience agreeing with you, they think you're "one of them" because you're obviously right or on their side on so many questions, and then you slip something in and you hope they'll just keep nodding yes, or if they question it, they'll think, "Oh, does that go with everything else he just said? I guess so."

It's not necessarily a "non-sequitur". I'm not looking for cases where the speaker presents a logical sequence of steps and one of the steps isn't valid. Rather, I'm thinking of cases where he just throws a bunch of ideas together, with no connection other than an implied, "These ideas all go together" or "These are all things that we all agree on" or "These are all things that are obviously true."

  • Here is a related question that you might find interesting.
    – Kit Z. Fox
    Nov 7, 2011 at 18:28
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    I suspect that skeptics.stackexchange.com would be better suited to this sort of question about logic classification than a philosophy group. Nov 7, 2011 at 18:36
  • See also (for a list of logical fallacies): Logic and Fallacies - Constructing a Logical Argument infidels.org/library/modern/mathew/logic.html Nov 7, 2011 at 19:34
  • @Randolf: Well, logic and rhetoric are normally considered branches of philosophy, that's what I was thinking of when I made that comment. Aristotle wrote a classic discussion of logical fallacies as part of his philosophical writings. But I don't want to get on a tangential argument about classification!
    – Jay
    Nov 8, 2011 at 16:47

2 Answers 2


I think it's a form of false analogy, in that the salesman presumably hopes his audience are dumb enough to think that just because he surrounds his questionable statement with irrelevant but undisputed truisms, the questionable statement somehow becomes "true by association".

  • That's the ticket right there (+1). I was thinking "logical fallacy" but "false analogy" highlights what it really is -- a collection of propositions (and in this case, unrelated propositions). Nov 7, 2011 at 19:29
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    @Jasper Loy: That's why I said it's only "a form of". It's not really anything in terms of faulty reasoning, because neither reason, or explicit claims, are actually involved (as JeffSahol says). About the equivalent of putting coffee beans under the grill when showing round prospective buyers - nothing to do with the main subject, but if you're not careful you can easily be influenced by such trivial manipulation. Nov 7, 2011 at 22:15
  • Hmm, true in a sense, the speaker is saying "X and Y are both examples of things that all scientifically-minded people would agree on", in that sense it's an analogy. It's also a non-sequiter in a sense: If you believe X than you must inevitably also believe Y." But I was hoping for a more specific term. I've heard this technique used a lot, and I just expected someone would have invented a specific word for it by now. Maybe not.
    – Jay
    Nov 8, 2011 at 16:41
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    @FumbleFingers: I'm sure people fall for it, or the salesmen and politicians wouldn't keep doing it. Any time I think about propaganda techniques, I start thinking, Have I fallen for this somewhere along the line? Sure, I'm spotting it THIS time because the speaker was clumsy about it. But maybe the last guy did it well and I didn't realize I was being sucked in. ;'-(
    – Jay
    Nov 8, 2011 at 16:45
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    Speaking for myself, if I hear what sounds like an irrelevancy being introduced into persuasive speech, my bullshit filter automatically kicks in. I think I'm more likely to dismiss a perfectly good product because of such poor sales patter than the other way around. Although I'm not a salesman, I think they do a useful job when they're competent and honest - but I just can't abide the (largely stereotyped) bad ones. Nov 8, 2011 at 17:22

There is no logical fallacy here because logic is not even being attempted. As the OP says, "I'm not looking for cases where the speaker presents a logical sequence of steps and one of the steps isn't valid." It is more a rhetorical device.

  • +1 -- Whenever I've heard speeches like that (usually from politicians), I've never been disappointed in my expectation of a sales pitch to follow for something that is either extremely difficult to sell, or is so ridiculous that it depends on overwhelming the skeptics with thoughts of "you lost me." Nov 7, 2011 at 19:52
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    Hmm, seems to me you could say that about all logical fallacies: "There is no logical fallacy here because the speaker's statement has no logic." That's the point. But if you prefer, call it "propaganda technique" rather than "logical fallacy".
    – Jay
    Nov 8, 2011 at 16:36
  • I like 'propaganda technique' ..but would still say there are techniques that employ logical fallacies, and others that do not employ logic at all
    – JeffSahol
    Nov 10, 2011 at 16:58

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