jmjm wrote:Hey mlsat
B.1.21. This is a necessary assumption question. In this question, choice A is a sufficient assumption but is it necessary?
One of the necessary assumption could be "the first doctrine precludes any psychological factors in explanations of historical events". Since the question asks for an assumption the argument depends on, isn't then choice A incorrect.
For example, non-economic factors can include both psychological and environmental factors. What A is saying is that for the conclusion to be drawn we must assume that all non-economic factors (psycho and environ) must be precluded by the doctrine. But it doesn't have to be so. Doctrine-1 can appeal to environmental factors along with economic factors and still be mistaken.
So negating A by saying that the first doctrine appeals to economic and environmental factors doesn't break the argument.
What an interesting question!
Technically, you're right - (A)
doesn't absolutely have to be true to protect the logic of the argument. (I'm not sure that I would actually agree that it's truly sufficient, but that's a sideline argument for another day.) The first doctrine (eco-doctrine) does not have to bare ALL non-eco factors for the conclusion to be workable, it just has to preclude "early childhood experiences".
What the answer choice really should have said was something like "The first doctrine precludes at least some noneconomic factors in explanations of historical events."
What answer choice (A)
really seems to be answering is the question of 'what was the author thinking?'. The author seems to be misreading the "must appeal to eco factors" as if it were "must appeal ONLY to eco factors". So, if I were to hazard a guess at what logical error the author was committing, I'd say it was probably that. But it doesn't perfectly fit the technical requirements for a necessary assumption - i.e., one that's required
This sort of imprecision on an LSAT answer choice is rare, so good catch. It's an excellent reminder that sometimes answer choices aren't perfect, even though the LSAT is normally extremely careful in their parameters. The older the test, though, the more likely there will be issues. SuperPrep B isn't old enough to be let off the hook quite so easily, but still.
This brings up an excellent strategy issue though. We talk a lot on these forums (and in LR books, blog posts, etc) about the difference between Necessary and Sufficient Assumptions. But it's worth noting that the vast majority of assumption questions are not testing the distinction between the two
. Many, many assumptions answers are actually both necessary AND sufficient. It's actually not all that common to have a Necessary Assumption question with an incorrect answer that is a Sufficient-but-not-Necessary Assumption. It's almost unheard of to have a Sufficient Assumption question with an incorrect answer choice that is a Necessary-but-not-Sufficient Assumption.
So, what does this mean for us in terms of practical and strategic thinking? Your first goal should always be to evaluate the premises and the conclusion and ask yourself what the GAP is between them. What's the fundamental disconnect that occurs between A and B? You should use this essential idea to eliminate things that aren't in the ball park. Now, if doing that gets you down to two answer choices, both of which are in the right vicinity and seem to address the gap, it's time to really slow down and hone in on the specifics -- including whether you're looking for something that will guarantee the argument will work, or whether you are looking for something that you require
in order for the argument even have a chance.
In this case, only (A)
actually addresses the essential gap between [an event having particular simultaneous causes] and [some doctrine being wrong]. If I were working through this question on test day, I would use that knowledge to eliminate the other four answers quickly. At that point, I'd double check (A)
, and to be 100% honest, in the heat of the exam at that point, I might not even notice that the answer was imperfect. If I did notice it, I'd allow myself just a split second of irritation before reminding myself that the other four answers were DEFINITELY not addressing that fundamental disconnect.
In short, this answer choice is imperfect, and the language really should have been softer/more careful, but the other four answers are still definitively and categorically wrong.
So, as I said above, good catch!