Question breakdown

Let's diagram the argument. "Only computer scientists understand the architecture of personal computers." Remember that "only" introduces a necessary condition. PR1: UAPC ==> CS not CS ==> not UAPC "Only those who understand the architecture of personal computers appreciate the advances in the technology made in the last decade." PR2: AAT ==> UAPC not UAPC ==> not AAT "It follows that only those who appreciate these advances are computer scientists." C: CS ==> AAT not AAT ==> not CS What can we properly infer from these premises? We can connect PR2 and PR1 like so: AAT ==> UAPC ==> CS to conclude: AAT ==> CS. The argument, however, has used the necessary condition to conclude the sufficient condition (i.e. CS ==> UAPC ==> AAT). Remember, don't just reverse; you must always switch the variable AND negate. "CS" is the necessary condition of the first principle rule. Thus, we cannot infer anything else from it. If you look at the necessary condition of PR1 and its contrapositive, you see that a viable option is to have a computer scientist who does not understand the architecture of personal computers. We know from PR2 that if you do not understand the architecture of personal computers, then you do not appreciate the advances in technology made in the last decade. Therefore, there can be a computer scientist that does not appreciate the advances in technology made in the last decade. So, answer choice (B), "The argument ignored the fact that some computer scientists may not appreciate the advances in technology made in the last decade," correctly identifies the flaw in the argument. Hope that helps! Please let us know if you have any other questions.

I still don't understand why it is B. The flawed reasoning doesn't say all computer scientists appreciate architecture.

@knoxygirl the conclusion says "only those who appreciate these advances are computer scientists." "Only" introduces necessary condition so this would be diagrammed as follows: CS ==> AAT not AAT ==> not CS But as mentioned in the comment above, this is the reverse of what you can actually properly conclude from the premises, i.e. AAT ==> CS. Hope this helps! Please let us know if you have any other questions.

I keep getting confused with diagramming "only" . I understand that it introduces the necessary condition, but aren't we supposed to negate the sufficient condition as well as a part of the two rules when diagraming "only"? for this questions I diagramed the first sentence of this question as: not UAPC==> CS

@kdehoyos you are correct that you negate the sufficient condition as part of the contrapositive, however here you have negated the sufficient condition without also negating the necessary condition and reversing the variables. The correct diagram is: UAPC ==> CS not CS ==> not UAPC It seems here like you possibly combined aspects of the original statement with aspects of its contrapositive. I hope that helps!

How is that a viable option? PR1 contrapositive indicates that if you're NOT a computer scientist (so, not "you are a computer scientist) that doesnt understand the architecture of a personal computer and therefore cannot appreaciate advances in technology.

I found the analogy that Mehram used in the lesson for this chapter of taking the LSAT being necessary for law school helpful for this question LAW SCHOOL - -> LSAT But not everyone who takes the LSAT will go to law school :)

@Maybeillgetlucky, (B) captures the flaw of the argument, which is confusing a sufficient condition for a necessary one. We have App - >UAPC - >CS The conclusion of the argument is CS - >App This is not a logical conclusion. Not all computer scientists have to appreciate the advances that have been made. Rather, the correct conclusion is actually if you appreciate the advances, then you must be a computer scientist CS - >App Thus, it's possible that there are some computer scientists who do not appreciate the advances. Does this make sense? Let us know if you have any other questions!

Great point about the analogy, as well! It looks like you have strong understanding of it :)

I saw the flaw as circular reasoning. The term "only" is used many times and each time I took it to introduce a necessary condition.