jmjm wrote:pt-36, rc:
Q2: Other answer choices (AC) in addition to the credited (c) can be argued to contain attributes that author has dismissed. AC (d) and (d) have both discrimination along educational/economic lines and lack of diversity (age for (b) and career for (d)).
The author never states that discrimination along these lines means that you don't have a community. That's an example of why a specific "community" shouldn't count as one, and it's meant to support the actual criteria offered by the author. The criteria the author uses to define a community shows up when he says, "Actual communities, on the other hand, are "nonintentional"". In short, a group that just happens to be in the same place can be a community; a group that intentionally comes together for a specific reason is not a community.
So in (B) and (D), we have people who happen to be located in the same geographical region. We didn't have a group of students all decide to form a university somewhere - we had a diverse group that ended up located in the same place and then found friends. Same in (D) - we had a group of teachers who ended up at the same school, and then they worked together. They didn't set out to all settle in the same school - they each ended up teaching there from different cities/neighborhoods.
(C), on the other hand, has a bunch of doctors specifically setting out to create a conference where there are just these doctors. They segregated themselves/set admission criteria, so they don't count as a community.
Q4: The credited AC is (e) even though the necessary criterion it states ("only if its members feel a sense of interdependence despite different economic and educational backgrounds") is always true for computer conferences and can't be used to refute the argument. Due to the use of word "despite" the above necessary criterion does not assert anything when "different economic and educational backgrounds" doesn't exist such as in computer conference.
I disagree with your reading of "despite". When it says that, as it does here, it means that having that diversity in backgrounds is in fact necessary, according to the author, for a community to exist, because they have to become interdependent in spite of their differences. If they don't have differences, they can't feel interdependent in spite of those differences, so they can't be a community because they can't have something necessary to a community.
PT-46 Sec-2 (LR-1) Q8:
answer choice (a) also weakens the argument strongly because it says that that schools need computers because "scientific knowledge is changing so rapidly". Therefore it directly weakens that premises of the argument which claim laboratory experiment to be most effective.
I am unsure if the above line of argument has been left in the answer choices by lsat writers deliberately or by accident.
Again, I disagree with your assessment. As a preliminary note, a correct answer on the LSAT will never directly weaken/contradict a premise. It will always go after the gap between the premises and the conclusion.
(A) does not, in fact, weaken the premise that lab experiments are the most effective method for teaching science. While knowledge is changing so rapidly that it is difficult for schools to keep up without computers, that doesn't mean that relying just on computers is more effective than lab experiments, or even that lab experiments are less useful. Maybe you need to have computers around to keep up with the info, but then you need to use that info in lab experiments to use the most effective teaching method. In short, even if (A) is true, it could still be true that laboratory experiments are the most effective method of teaching science, so (A) has no effect on the argument.