Logical Reasoning

PT146 · S1 · Q14 Ethicist: The general principle

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Ethicist: The general principle—if one ought to do something then one can do it—does not always hold true.

Conclusion

There are exceptions to the principle that . (i.e. at least sometimes, you ought to do something but can’t do it)

Evidence

Some promises to meet a friend at a certain time, but they can’t (an unforeseen traffic jam thwarted them).

Evaluate

For the author to successfully show a counterexample to the general principle, she must clearly establish a case in which a) you ought to do X b) you can’t do X

In her example, have both things been established? X = meet someone at a certain time

It’s established that our person can’t do X (they can’t meet their friend at the agreed-upon time because of the traffic jam).

Has it been established that our person ought to do X? No. We just know that the friend promised to do X.

Goal

The author is assuming

14.

Which one of the following is an assumption required by the ethicist's argument?

If a person failed to
Too Strong
Too Strong: all failures come from promises This confusingly can look like a contrapositive of what we wanted. We wanted, promised to do X → ought to do X ~ought to do X → ~promised to do X That contrapositive is saying, “If a certain action wasn’t something you ought to have done, then it wasn’t something you promised to have done”. The rule in this answer is saying “If you failed to do something you ought to have done… “ There’s a big difference between “Action X wasn’t something you ought to have done” and “Action X was something you ought to have done, but you failed to do so”. If you think about this answer conversationally, rather than symbolically, it’s easier to hear how this is way too strong an idea. The author’s assumption is a pretty moderate real world principle: if you promised to do X, you should do X. This answer is a crazy extreme real world idea: If you should have done X but failed to do so, you must have promised to do X. Huh? I should have brushed my teeth this morning, but failed to do so. That means that I promised to brush my teeth? I should have filed my taxes on time, but I failed to do so. According to this rule, that proves that I promised to file my taxes on time?
30% picked this
Only an event like an
Too Strong: only traffic jams
Our author isn’t assuming anything about traffic jams being a special, unique type of thing. It was just a random example she plucked out of the thin air. This would look like this … excused from promise —> traffic jam Is that a reasoning move the author made? No. In fact, is the author even thinking this reversed version? if there’s a traffic jam, then you’re excused from the promise No, the opposite. The author is assuming that this is an example of someone who should still be keeping their promise.
5% picked this
If there is something that
Out of Scope
Out of Scope: ought not to do Nothing in this argument deals with things we ought not to do. There are three possibilities: you ought to (call your mom), you ought not to (ignore your mom), or other things (tapping your foot to the song on the radio (we’re not saying you ought to or that you ought not to). The author’s argument is only about that first category of actions, whether or not things you ought to do only consist of things you can do. If we looked at this conditionally, it’s saying ought not to do X → not capable of doing X capable of doing X → ought to do X This is an illegal reversal of the principle that the author is arguing against.
11% picked this
Correct
The obligation created by a
Why this is right
If we negate this answer, it says “the obligation created by a promise is relieved by the fact that the promise cannot be kept”. Does that weaken the argument? Yes! Remember the author was assuming, “If you promised to meet your friend, then you ought to keep that promise.” Negating this answer is saying, “No, you don’t need to keep that promise. Your obligation to keep that promise was relieved by the fact that the promise cannot be kept. We moral judges wouldn’t be looking at you in the traffic jam, thinking, ‘How dare he. He should be keeping his promise’.” Answers on Necessary Assumption that have the word “not” are ripe for the Negation Test. When we remove the word “not”, does it turn into an Objection? If so, pick it! If you prefer thinking about the positive version of this answer, remember that our author thinks that “If you promised to meet your friend at a certain time, then you ought to do so.” This answer is just reinforcing that: “Don’t think that you’re off the hook just because of the traffic jam. The obligation created by your promise doesn’t disappear just because you can’t keep the promise anymore.”
Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.
53% picked this
If an event like an
Out of Scope
Out of Scope: should not have made promise The author is never discussing a situation in which someone shouldn’t have made a promise. We’re talking about a situation in which someone should keep a promise, but can’t. The first half of this conditional could work, but the second half would have to be tweaked: traffic jam interferes person still ought with person → to keep promise keeping promise
2% picked this

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