Using extreme examples

Scenario §

A company makes a mini magnet toy for kids. Each package it sells has hundreds of tiny ball magnets.

Alice: It is morally condemnable for the company to report injuries in terms of injuries per magnet (1 in 22 million) instead of 1 injury per 100,000 sets.

Bob: I don’t see anything wrong with it. The same information is provided, no matter the unit.

One strategy Alice can use in this disagreement is an extreme example. One way of making sense of how an extreme example functions:

General case	This particular case
Bob claims an explicit position $\varphi$. Some casual / loose reasoning is all that’s needed to be entitled to this, under normal circumstances.	$\varphi$=“It’s not morally wrong to report in terms of injuries per atom”
Alice suspects he derives $\varphi$ from some bad principle $P$, which is the most natural way of making Bob’s loose justification more precise.	$P$=“As long as it has the same literal informational content, it’s equal from a moral standpoint.”
$P$ is bad because it would also license one to make an absurd claim, $\perp$.	$\perp$=“It’s ok to report in terms of injuries per atom.”
Bob is not entitled to use $P$ (and needs a more explicit reason to be entitled to $\varphi$).	Bob needs to clarify why what the company did isn’t morally wrong.

I see this kind of move very frequently when reading comment sections of all sorts (a guilty pleasure). Often it’s executed poorly.

Inappropriate usage: two pitfalls §

Edginess: Alice uses an emotionally-triggering $\perp$, despite there being plenty of other absurd consequences of $P$ that would suffice.

Alice: So you’d be fine if they said “The chance of a child’s injury is less than 1/1000 of the chance of dying in a school shooting”?

Patronizing: Alice doesn’t acknowledge that $P$ is something she is hypothesizing Bob endorses. Now it seems like she thinks Bob actually believes $\perp$, rather than merely that he’s not entitled to $\varphi$.

Alice: If you think that, then you wouldn’t mind if they reported it in terms of injuries per atom sold!

Bob: Feels completely misunderstood / insulted, becomes hostile

Appropriate usage §

We need a modification to the second scenario above in order avoid that pitfall:

• Ask “Would it be morally condemnable for the company to report injuries per atom sold?” and let Bob draw the distinction himself. However, even this could be perceived as accusing him of believing $\perp$, if Alice and Bob don’t know or trust each other.

• More diplomatic is presuming Bob doesn’t believe $\perp$ by asking “Why is it the case that you’d draw the line between injury per magnet and injury per atom?”