by fmuirhea Tue Feb 05, 2013 7:55 am
This is a principle strengthen question (so, similar to sufficient assumption) where you're looking for an answer choice that virtually guarantees that the conclusion follows from the premises.
P: dried parsley is less tasty and healthful than fresh parsley
C: dried parsley should never be used in cooking
The conclusion is quite strongly stated. Why shouldn't we ever use dried parsley? There are no guidelines given to us in the premises that would tell us when we can and cannot use certain herbs; they only state some facts about dried parsley.
We need an answer choice that shuts down this gap/shift: we move from parsley characteristics to an all-out prohibition on its use. Many principle strengthen questions are simply a matter of stating "if P, then C." (Although there was a much trickier one on this test: 2.16)
The strong term "only" in (B) sets up a conditional statement:
ever used in cooking --> tastiest ingredient
It's actually the contrapositive we're interested in:
~tastiest ingredient --> never used in cooking
Since the premise explicitly tells us that dried parsley is not the tastiest (i.e., it is less tasty than fresh parsley), this allows us to connect premise and conclusion. (An answer choice that claims that only the most healthful ingredients should ever be used would be just as fine, too.)
(A) actually isn't strong enough, since the conclusion says that parsley should never be used. If (A) were the case, it would give us a reason to choose fresh over dried provided both were available, but what if dried parsley were the only option? Could we use it then?
You're right that the prompt never says anything about using the tastiest ingredients all the time - for this question type, your task is to provide that missing piece! Think of principle strengthen and sufficient assumptions as giving you another premise. Once you add it in, does the conclusion follow?
P: dried parsley is less tasty and healthful than fresh parsley
P: ~tastiest --> never used in cooking
C: dried parsley should never be used in cooking