#14 - Ethicist: The general principle—if one ought to do

[Jeff Wren]

Complete Question Explanation

Assumption. The correct answer choice is (D)

The stimulus begins with the argument's conclusion, namely that the principle that "if one ought to do something, then one can do it" is not always true. In other words, the conclusion is expressing the idea that there may be situations in which one ought to do something even though one can not actually do it.

To support this conclusion, the argument then provides a counterexample which is meant to show a situation in which someone ought to do something (in this case, keep a promise) even though that person cannot actually do that thing (due to the unforeseen traffic jam). The problem, though, is that the counterexample doesn't actually establish that one "ought" to keep a promise at all, much less when it is impossible to keep. In order for this counterexample to make sense and effectively support the conclusion, the argument needs to assume that:

1. One ought to keep one's promises as a general matter.
2. Even if it is impossible to keep a promise, that doesn't "get you off the hook," you still should have kept the promise, even though you can't.

These both work as possible prephrases, and the correct answer is a version of number 2.

One element that makes this question tricky and confusing is that, in the real world, we would likely assume that if you cannot do something, then you are no longer obligated to do that thing. For example, if you promise to attend a friend's wedding but you then get in a car accident and are in a coma, then it would be odd to maintain that you still "ought" to keep that promise. However, this is exactly the type of reasoning used in the argument: that impossibility doesn't "get you off the hook" in terms of what you "ought" to do. The LSAT often uses counterintuitive ideas to confuse test takers.

Answer choice (A): This answer is like a Mistaken Reversal of the first assumption listed above. The assumption that the argument does make is if one makes a promise, then one ought to keep it. That does not imply that if you ought to do something, then it must be something that you promised to do (or failing to do something you ought to have done means that you failed to do something that you promised to do, as Answer A states). Keeping a promise is just one type/example of something that you ought to do, but there very well may be other things that you ought to do (e.g. refrain from committing felonies) besides keeping promises.

Answer choice (B): This is essentially an opposite answer. The argument assumes that the traffic jam does not excuse a person from the obligation to keep a promise, which is why that example is provided to show a situation in which the principle does not hold true. In other words, the example is meant to show a situation in which one is still obligated (i.e. ought) to keep the promise, but cannot.

Answer choice (C): This is also essentially an opposite answer. The principle (which the argument rejects) is that "if one ought to do something, then one can do it." This answer gets at the same idea as the principle, but with using idea of "ought not' rather than "ought" to be confusing. However, whether a person "ought" to do something or "ought not" to do something is largely semantics. For example, the argument assumes that one "ought to keep a promise," but we could reword that idea to assume that one "ought not break a promise." Using this example, this answer states that if you "ought not break a promise," then you must be capable of not breaking that promise. Similar to the original principle, this is basically the opposite of what the argument is assuming. The argument is assuming that you "ought not break a promise" even if you are not capable of not breaking the promise. That is the point of the counterexample to show a situation in which someone "ought not break a promise" even though it is impossible for that person to not break that promise.

Answer choice (D): This is the correct answer choice. As discussed above, the argument assumes that one ought to keep a promise even if one cannot actually keep it (due to no fault of their own). This is why the counterexample shows that the principle "if one ought to do something, then one can do it" is not always true because the example is showing a situation in which one ought to keep their promise, even though it that person cannot keep it.

Applying the Assumption Negation Technique for Answer D, we get "The obligation created by a promise is relieved by the fact that the promise cannot be kept." This negated statement weakens the conclusion because now, the fact that one cannot keep a promise does "get you off the hook" and you are no longer obligated to keep the promise. In other words, based on the negation of Answer D, if you cannot do it, you no longer "ought" to do it. What this would mean is that this counterexample does not show a violation of the original principle because it no longer is showing something that one ought to do, even though that person cannot do it.

Answer choice (E): There is no discussion in the argument regarding when one should or should not make a promise, so this answer is irrelevant to the argument. The only issues about promises relevant to the argument are whether one ought to keep them when they are made (yes, assumption 1) and whether the fact that it becomes impossible to keep a promise relieves one of the original obligation of the promise (no, assumption 2).

[lsatstudent]

Hello!

This is one of the LR questions I got wrong on the test. I originally answered A.

My thought process:

The question doesn't seem to have a gap in logic so this must be a defender assumption.
A
B would weaken the argument
C not relevant to this argument
D
E doesn't seem to be necessary for the argument to be true.

I don't fully understand why A is incorrect. Is A a shell game? Why is D correct?

Thank you,

Confused LSAT student

[Nikki Siclunov]

Hi lsatstudent,

Thanks for your question. The author considers the following principle: if you ought to do something, then you can do it. In conditional terms, the principle can be diagrammed as follows:

• Ought to do Can do

The principle is rejected as being inconsistent with a purported counterexample, whereby you can't keep a promise you've made (for reasons beyond your control). The counterargument is not iron-clad, as there is no evidence that you necessarily ought to do the things you promise to do. Are promises necessarily obligations? And if they are, are there any circumstances in which they can be relieved? This line of reasoning brings us to answer choice (D). To test if (D) is an assumption, use the Assumption Negation Technique and examine if the logical opposite of that answer weakens the conclusion of the argument:

• Logical Opposite of (D): The obligation created by a promise is relieved by the fact that the promise cannot be kept.

Clearly, if the impossibility of keeping the promise relieves the obligation created by it, then the counterexample does not really refute the original principle. After all, if you no longer ought to do the thing you promise to do, the principle in question wouldn't even be triggered in the first place: the principle concerns actions you are obliged to do ("if one ought to do something...'), not actions you are off the hook for.

I realize you're considering answer choice (A) as a contender, and I can see why: it attempts to connect the two central elements in this argument. However, it's indeed a Shell Game. In the counterexample given, our friend failed to keep a promise, which is not tantamount to failing to do something she ought to have done. In other words, we haven't established that anyone has failed to do something they ought to have done, because a promise is not necessarily an obligation. If you're still considering answer choice (A), try the Assumption Negation Technique:

• A person can fail to do something they ought to have done without necessarily failing to do something they promised to do.

Given that we haven't established whether the person in question ought to have met the friend at a certain time (they only promised to meet him), the implications of the logical opposite are moot.

Hope this clears it up! Let me know if you have any other questions.

Thanks,

[ChicaRosa]

I also choose A for this one too! Is it wrong because it's a mistaken negation of the principle in the stimulus?

Thanks!

[Adam Tyson]

Not exactly, ChicaRosa. The MR of that principle would be "if you can do it then you ought to do it." Answer A brings up something else - the "promise" concept. There is another assumption in this argument, although it ends up not being the one we are looking for, and that is that you ought to do the things you promise to do. Conditionally, that would be:

P(romise) O(ught to do it)

A good contrapositive would be:

O P

Answer A somewhat misstates that contrapositive by twisting into being about failing to do something, rather than that thing not being something you ought to do. In a sense, it's also a Mistaken Reversal of the original claim above (which, remember, was not in our stimulus, but is another assumption built into the stimulus). The answer is based on the belief that anything you ought to do must necessarily be something you promised to do.

I promise that I was trying to help clear things up, and I know I ought to be doing that, so I hope I didn't fail!

[tayloramalkin]

Does the phrase "does not always hold true" have any impact on the conditional statement? Wouldn't that be the authors conclusion and the example would be its support?

[Adam Tyson]

You got it, Taylor! The claim that the original conditional claim "does not always hold true" is another way of denying the absoluteness of the conditional claim. In other words, the necessary condition really isn't necessary. There can be things you ought to do that you cannot do.

The example is supposed to show that - something that you ought to do (because you promised) that you nevertheless cannot do. That's the premise supporting the conclusion that the conditional claim is not always correct.

The assumption is that you still ought to do what you promised, and that the inability to do it doesn't cancel out the "ought".

Nice work!

[Etsevdos]

You got it, Taylor! The claim that the original conditional claim "does not always hold true" is another way of denying the absoluteness of the conditional claim. In other words, the necessary condition really isn't necessary. There can be things you ought to do that you cannot do.

The example is supposed to show that - something that you ought to do (because you promised) that you nevertheless cannot do. That's the premise supporting the conclusion that the conditional claim is not always correct.

The assumption is that you still ought to do what you promised, and that the inability to do it doesn't cancel out the "ought".

Nice work!

'

I have seen question prompts like this in a couple instances: how would you diagram conclusion:

Out to do something--> you can do it

Arg the says this does not hold true: should we always negate necessary (not sufficient). Therefore, I believe (as you mention above), the authors actual conclusion would be written as : ought to do something-->you cannot necessarily do. The premise is essentially: Promise--> cannot necessarily do it.

Now, answer D: connects gap in jump from ought to do something in conclusion as sufficient to promise--> cannot necessarily do. Negating D: Promise--> you should do, makes the authors argument fall apart.

How would you diagram and negate A though?

[Adam Tyson]

Good analysis, etsevdos, although don't be afraid to be a little less mechanical and a little more holistic in your approach. While conditional diagramming is a useful tool, it is one that is often overused by students who could have gotten there easier and more naturally from a more commonsense approach.

My approach to answer A would be more holistic than diagrammatic. I read it as "if you failed, then you promised" (which leaves out the "oughts" but still captures the essential nature of the claim). My negation would be "failing doesn't mean you promised" or "I can fail at something even if I didn't promise to do it".

Mechanically/diagrammatically, I would probably tackle A this way:

FSOD (Fail at Something you Ought to DO) PD (Promised to Do it)

The negation of a conditional statement is not simply negating the necessary condition - it's showing that the conditional relationship is, in fact, untrue. So from a purely diagrammatic approach, I would simply take the entire diagram above and cross it out. That, to me, would mean "this is not a true claim". I would NOT negate the necessary condition, like this:

FSOD PD

Because that means failing proves that you did NOT promise, and that is not the same as saying that failing does NOT prove that you promised. It's too strong, and is the polar opposite when what we want is the logical opposite.

Be more holistic in your approach, and when dealing with conditionals you can negate them by simply saying that the sufficient condition is not, in fact, sufficient to prove the necessary condition. In other words, the sufficient condition can happen EVEN IF the necessary condition does not. The necessary isn't necessary, the sufficient isn't sufficient, the whole thing just isn't true.

I hope that helps. Keep up the good work!

[meercat44]

I'm having trouble wrapping my head around this one.

Looking at this -

Logical Opposite of (D): The obligation created by a promise is relieved by the fact that the promise cannot be kept.


Wouldn't this then help the Ethicist's argument? Proving that the principle "does not always hold true?"