Proper name for "affirming the common ground" fallacy / rhetorical technique?

Question

I'm trying to find the name for this form—I don't know if it'd rightly be called a "fallacy", or just a "rhetorical technique"—where you affirm or reiterate non-disputed premises of your argument—the common ground between those who hold A and those who hold ¬A—as if it supports whatever your stance is, be that A or ¬A.

So if your argument goes P1; P2; P1^P2→A; A, and most people who hold ¬A hold P1^¬P2, you will nevertheless present P1 as if it's characteristic of your position, despite the fact that it's equally characteristic of most natural persons who hold the opposite position.

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The real-world examples that inspired this question (I've seen this only in political contexts so far, as I expect it would fall apart in any formal setting):

P1: I have the right to make decisions about my body
P2: Abortion is a decision about my body
Conclusion: I have the right to abortion

P1: Children should not be exploited or abused
P2: Gender transition is exploitation or abuse
Conclusion: Children should not be gender transitioned

In the first argument, P2 is disputed by opponents of the conclusion, but P1 is presented as being in pro.

In the second argument, P2 is disputed by opponents of the conclusion, but P1 is presented as being in pro.

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I have heard this tentatively characterized as a "red herring", but that term seems to be both too broad and a slightly awkward fit: in this form, P1 does form a necessary part of the argument for A—it's not irrelevant, as you would get the opposite conclusion by negating it.

“I do not have the right to make decisions about my body”; “Children should be exploited or abused”: either of these would negate their respective conclusions, ceteris paribus. These propositions are not irrelevant to the conclusion, so I feel like it stretches the definition of "red herring". But I can't find the proper terminology for this "special edge case" of that fallacy. Is there established terminology for this, or existing literature on this rhetorical phenomenon?

Answer 1

I don't think this is a fallacy, and while it might be categorized as a rhetorical ploy, it's honestly just part of reasoned argumentation. What's lacking (usually) is followthrough, but that's a separate issue.

For instance, let's look at your first case:

P1: I have the right to make decisions about my body
P2: Abortion is a decision about my body
Conclusion: I have the right to abortion

The first premise is naturally an assertion about a characteristic of a class of objects. I could make the following simple syllogism, and it would be perfectly valid:

P1: All humans have the right to make decisions about their bodies
P2: Kumquat Joe is a human
Conclusion: Kumquat Joe has the right to make decisions about his body

We could debate both P1 and P2 — Are such decisions about bodies natural rights? is someone named Kumquat Joe actually a human? — but if we accept both premises, the conclusion follows logically. There is noting wrong with choosing a generally accepted moral principle as the first premise. In fact, doing so makes the argument stronger, because then you only have to argue about the second premise.

So now, we start chaining syllogisms together. We start with:

P1: All humans have the right to make decisions about their bodies
P2: Each woman is human
Conclusion: Each woman has the right to make decisions about her body

That gives an expanded version of your statement, as follows:

P1: All humans have the right to make decisions about their bodies
P2: Each woman is human
Conclusion 1/P3: Each woman has the right to make decisions about her body
P4: Abortion is a decision about the body
Conclusion 2: Each woman has the right to abortion

What this lays out is an argument meant to convince people. We want each point in the argument to be convincing in its own right, because an opponent can argue against each point to try to disrupt the argument:

• Do all humans have complete rights over their bodies? (e.g., what about suicide or self-harm?)
• Are women actually human in the sense meant? (biblical fundamentalists have argued against that idea)
• Is abortion a decision about a woman's body? (or is it a decision about a fetus' body?)

These are all possible approaches to countering this argument, and in a good intellectual discussion — one with followthrough — people would spend time thinking about and expanding on theses points to make their argument stronger and more convincing. But the standard mass and social media environments have very few openings for followthrough, so instead people find themselves hammering on the bullet points to try to convince people through sheer, mindless repetition. It's a sad feature of the modern world — the degradation of intellectual debate — but it's not fallacious by any means, or wrong in any real sense. It's just, you know... sad.

Answer 2

Short Answer

No. This isn't a fallacy. Yes. There is a common term for this phenomenon in rhetoric. It's called "framing the debate or argument". Framing in a more extended sense has become an important idea both in the social sciences and in linguistics where both socially constructed reality and context in text are statements about how humans manifest normativity in regards to language.

Long Answer

Fallacy, a topic generally dealt with by philosophers of logic, has to do with bad inference. What you present is a technique to persuade, and is rhetorical. Framing is selectively trying to convince others of which position is an accurate characterization, which in the non-literary sense, means simplification or analogy. Let's take your example.

The pro-choice position in the controversy over abortion paints their opponents as anti-choice and violating a woman's body. The pro-life position paints their opponents as anti-life and violating morality. Both sides appeal to the fact that most people are both against being told what to do with their body and yet are also against perpetrating harm to children. So, the pro-choice side affirms the common ground by emphasizing choice, and the pro-life side affirms the common ground by emphasizing morality. Both sides attempt to "frame the debate" by characterizing the scenario in a way that supports their thesis. In this sense, while neither side necessarily engages in specious inference, the argument in an extreme might be considered a false dilemma.

For instance, in the US, religious pro-life advocacy continues to push for a definition of human being that starts at conception. Historically in the Anglo-American tradition of law, quickening, and not conception has been that point. By redefining a zygote as a human being, opponents of abortion can argue for an outright ban. On the other hand, pro-life opponents may take an equally non-traditional point and argue that the viability of the fetus is what makes a life human. In this way, pro-choice lobbyists are trying to extend the legality of abortion past the quickening.

Thus, if one is against the killing of a human being, the definition of what it means to be a human being is where the argument is to be had. Humans are flexible in this way, and consider how under slavery adult members of Homo sapiens can be declared non-human. This sort of splitting of hairs is the stuff argumentation, particularly the legal sort. Interestingly, there's an emerging body of evidence from cognitive science that selecting definitions and political positions is aligned with our biology.