Self-study
A person's failure to keep a promise is wrong only if, first, doing so harms the one to whom the promise is made and, second, all of those who discover the failure to keep the promise lose confidence in the person's ability to keep promises.
Objective: Apply the Principle
The stimulus gives us a principle, which we need to correctly apply. To do this, we have to understand what possible valid outcomes the principle can yield. The principle gives us two necessary conditions for promise-breaking to be wrong: (1) breaking the promise must harm the person to whom the promise was made (the "promisee"), and (2) everyone who learns about the broken promise must lose confidence in the promisor's ability to keep promises.
wrongbreak promise → harm promisee
wrongbreak promise → lose confidence in promisoreveryone who learns
Since we're dealing with a sufficient-necessary conditional relationship, there are two ways we can validly apply the principle. The first is to deny one or both necessary conditions to deny the sufficient condition. So if we can say a broken promise didn't harm the promisee and/or didn't cause someone who learned about it to lose confidence in the promisor, we can say that it wasn't wrong to break the promise.
The second way is to affirm the sufficient condition to affirm both necessary conditions. If it was definitely wrong to break a promise, that lets us infer that breaking the promise harmed the promisee and caused everyone who learned about it to lose confidence in the promisor. The correct answer must follow one of these two patterns, because these are the only valid ways to apply the principle.
23.
Which one of the following █████████ ████ ███████ ████████ ██ ███ █████████ ██████
a
Ann kept her ███████ ██ █████ ███████ ███ █████ ███ ████ ████ ████████ ████ █████████ ████████ ███ ████ ███ ████ ███ ██ ████████████ █████ █████ ███████ ███ ███████ ███ ███ ██████
The principle is about when breaking a promise can be wrong. Since (A) is about keeping a promise, it doesn't work as an application.
b
Jonathan took an ████ ██ ███████ ██████████ ███ █████████████ █████████ ████████ ███ ██ ████ ████ ██ █ ███████████ ███ ██████ ███ █████ ████ ██████ ███ ███████████ ████████ ████ ██ ████ █████ ███████ ██ ███ ████████████
(B) says that breaking an oath—which, sure, counts as breaking a promise—is wrong, but doesn't make appropriate inferences that would match our principle. This isn't a proper application, because even though (B) affirms the sufficient condition, it doesn't go anywhere with that.
c
George promised to █████ █████ ███ █████ ██ ████ ████ ████████ ██████ ███ ██████ ██ ████ ███ ███████ ██ █████ ███ ██ █ ███████ █████ ████████ █ ███████ █████████ █████ █████ ████████ ███████ ██ ████ ███ ███████ ███ ██████
(C) commits a classic logical fallacy: affirming a necessary condition. (C) says that because a necessary condition (harming the promisee) was met, the sufficient condition (being wrong) is also met. But that's working backwards—we can only validly affirm the sufficient or deny the necessary.
To make things worse, (C) also omits the second necessary condition of making people lose confidence in the promisor.
d
Because he lost ███ ████ █████ ███ ██████ ██ █████ ███ █████ ██ ████████ ██ ███████ ████████ ██████ ███ ███ ████ ████ █████ ███ ███ ███ ████ ██████████ ██ ███████ ███████ ██ ████ █████████ ███ ███████ ███████ ██ ████ ███ ███████ ██ ██████ ███ ███ ██████
(D) denies both necessary conditions: the broken promise didn't harm Miriam, and she also didn't lose confidence in Carlo. This lets us deny the sufficient condition to say that Carlo's action wasn't wrong—a valid application of the principle.
e
Elizabeth promised to ██████ ███ ████ ███ ████████ ████ ██████ ██████ █ █████ ███ ███ ███ ██████ ██ ██ ██ ███████ ███ ██████ ███████ ████ ███ ███████ █████ ██████ ████ ██████████ ██ ███ ███████ ██ ████ █ ████████ ███ ███████████ ███████ ██ ██████ ███ ████ ██ ██████ ███ ██████
Like (C), (E) proceeds by affirming a necessary condition in an attempt to affirm the sufficient condition. But because this is a logical fallacy, it can't be a valid application.