It is a mistake to conclude, as some have, that ancient people did not know what moral rights were simply because no ...

Rinku on November 18, 2013

Strengthen with necessary premise

Could you please explain this reasoning behind this answer?

1 Reply

Melody on November 20, 2013

Here we have a Strengthen with Necessary Premise question. Remember that a premise is necessary for a conclusion if the falsity of the premise guarantees or brings about the falsity of the conclusion. First we check to see if the answer choice strengthens the passage, and then, if it does strengthen, we negate the answer choice to see if its negation makes the argument fall apart. If the answer choice does both those things then it is our correct answer.

The conclusion in the argument is: "It is a mistake to conclude, as some have, that ancient people did not know what moral rights were simply because no known ancient language has an expression correctly translatable as "a moral right." Why? Because this would be like saying "that a person who discovers a wild fruit tree and returns repeatedly to harvest from it and study it has no idea what the fruit is until naming it or leaning its name."

(A) is incorrect because it is irrelevant. Answer choice (A) is diagrammed:

KNS ==> KWI
Not KWI ==> not KNS

We know that no known ancient language has an expression correctly translatable as "a moral right." So, "not KNS." The argument claims that it is incorrect to conclude: not KNS ==> not KWI. The statement in answer choice (A) does nothing to the argument. As you can see from the necessary conditions of the principle rule and its contrapositive, KWI and not KNS can occur together. Therefore, this answer choice does not affect the passage.

(B) is incorrect because it is irrelevant. The degree to which people know something has no affect on the passage. We merely want to know whether or not ancient people knew what "a moral right" was, not to what extent they knew.

(C) is incorrect. Even though it somewhat strengthens the argument, it does not pass the second step. It strengthens by showing that the name of something provides no information about the nature of the thing that is identified. Therefore, it helps support the passage by furthering the point that just because ancient people did not have a name for "a moral right," that does not mean that they did not have information about the nature of a moral right. Now, let's negate: "The name or expression that is used to identify something can provide some information about the nature of the thing that is identified." So that means that placing a name to "a moral right" would have given ancient people SOME information about the nature of a moral right, however, it would not necessarily have given ancient people ALL the information about the nature of a moral right. Thus, there is still room for the possibility that ancient people did not have a name for "a moral right," but still knew what it was. So, answer choice (C) has not passed both tests.

(D) is CORRECT. The author uses the example about the wild fruit tree to show why those who thought ancient people didn't know what "a moral right" meant due to their lack of a word for it was ridiculous. Therefore, the wild tree example is just as wrong as the people who believe that ancient people did not know what "a moral right" meant. Thus, answer choice (D) strengthens that by showing that a person, who repeatedly harvests from a wild fruit tree and studies it, HAS SOME IDEA of what the fruit tree is before knowing a name for the fruit. Now let's negate: "A person who repeatedly harvests from a wild fruit tree and studies it has no idea of what the fruit is even before knowing a name for the fruit." This completely breaks his only evidence presented for his conclusion. He gives the wild fruit tree example to show how ridiculous it would be. However, if it were actually true that a person who repeatedly harvests from a wild fruit tree and studies it has no idea of what the fruit is even before knowing a name for the fruit, then the author has no support for his conclusion and therefore, the argument falls apart.

(E) is incorrect. It technically strengthens the argument because if one does not need to know what something is before one can name it, then just because something doesn't have a name doesn't necessarily mean that it is something unknown. However, when we negate it: "one need know what something is before one can name it," it does not make the argument fall apart. The negation means that first one must know what something is, before it CAN be named. This would be diagrammed as follows:

N ==> K
not K ==> not N

However, no name is our necessary condition here so it tells us nothing else. Therefore, there could be a period of time where one knows what something is and has yet to name it, but CAN. As such, this does not make the argument fall apart.

I hope that was helpful! Let us know if you have any other questions.