Reply To: Prep Test #62

July 19, 2016 at 11:40 pm #2274
LSAT Dan
Participant

Sorry for the delay! This is a sufficient assumption question, so the right answer has to get us to the conclusion. So step 1 is to identify the conclusion, which is “One should never sacrifice one’s health to sacrifice money.” If you weren’t sure that’s the conclusion, you can get there by process of elimination – “For” is a premise indicator, so the other part of the passage is a premise.

So here’s how (A) works to guarantee the conclusion (when combined with the stated premise):

There are two ways to translate (A). Your (preliminary) goal is to get rid of the “only,” to create a straight up if-then statement (this should be your goal when you have to diagram an “unless” statement, also). When translated, (A) says, “If acquiring money would make happiness unobtainable, then you should not do it.” My method of translating “only” statements differs from the way they’re usually taught; you may have translated it to “If you should obtain money, then it will not make happiness unobtainable.” That’s not wrong, logically (notice that it’s the contrapositive of my version, which means it’s logically equivalent), but it’s not the most helpful construction, because it’s the effect on happiness that’s the triggering condition, and usually, that means it will be more helpful if that’s on the left side of the arrow.

But back to the passage, with the addition of (A) (notice that when evaluating any answer choice on a sufficient assumption question, you just go ahead as assume it’s true (as the question stem says). Here’s the passage + (A):

1. If you don’t have health, you can’t have happiness. (Premise from passage)
2. If it means you can’t have happiness, you shouldn’t obtain money. (A)
3. (Conclusion) If it’s going to cost you your health, you shouldn’t obtain money.

Notice that the first two (the premises) lead you to the conclusion, which is what you’re looking for in a sufficient assumption question.

A couple of practical tips that can zero you in on (A) here. Broadly speaking, there are two types of statements – descriptive, and normative. The normative statement is essentially a moral judgment – it says that something is good or bad, or right or wrong, or in this case, that you should or should not do something. This is a very reliable tip (though not surefire) – You can’t go from descriptive premises to a moral conclusion. When you see a moral conclusion, there has to be a parallel moral premise. In other words, when the conclusion tells us that we “should not” sacrifice health to obtain money, there HAS to be a premise that tells us under what conditions you shouldn’t sacrifice health. Notice that NONE of the other answer choices give us that “should” statement, except (C). But (C) doesn’t lead to what we need it to – sacrificing health. It tells us about how health should be “valued,” which doesn’t tie into the argument at all. On general principles here, without diagramming or wrapping your head around the argument, (A) is really the only answer that *could*’be right.

Here’s another shortcut to (A). Again, not surefire, but pretty reliable, especially when he passage is short. On an assumption question, look for a key term in the conclusion (in this case, money). You can’t reach a conclusion about money unless you have a premise about money. Since we don’t have a stated premise about money, there must be an UNstated premise about money. And what’s another word for an unstated premise? An assumption.

The answer choices are the possible assumptions – now we know that we need one that includes money. What is money going to be tied to? The term that appears in a premise, but then disappears – Happiness. It’s mentioned in a premise, but then it goes away. The argument jumps from happiness (in the premise) to money (in the conclusion). The right answer will link those two, as (A) does.

But what about health? That’s the million dollar question. In a conditional logic, 2-premise argument, on an assumption question, you’re going to have two main terms. The one that appears TWICE in the passage generally isn’t going to be part of the right answer. Notice, we have reference to health in both the conclusion and the premise. That pretty much means it’s not part of the right answer, and (B), (C), and (E) can be dismissed immediately! How can I make such a blanket statement? To answer that question, we have to consider the basic structure of a simple connected premises argument, and also the basic structure of an assumption question. First, the argument:

A–>B
B–>C
Therefore A–>C

Example:
All poodles are dogs.
All dogs are mammals,
Therefore, all poodles are mammals.

Notice, each term appears twice in the completed argument. “Dogs” appears in each premise, and “poodles” and “mammals” both appear in the conclusion and in one premise. Hold that thought.

Now, let’s look at the structure of a sufficient assumption question. An assumption is just a missing premise. To make this a sufficient assumption question, we need to remove a premise. That premise then becomes the right answer. Let’s remove the second premise. So the passage now is:

All poodles are dogs. Therefore, all poodles are mammals.

Notice that the term “poodles” appears twice. Also notice, it’s not part of the right answer, which is “All dogs are mammals.” The right answer connects the two terms that only appear once – dogs and mammals. The term that appears twice isn’t part of the right answer. We can disregard it.

What if we removed the first premise, instead? Then the passage would be:

All dogs are mammals. Therefore, all poodles are mammals. Now, the right answer is “All poodles are dogs.” The term that’s not part of the right answer is different – mammals. But it’s still the only one that appears twice in the passage. It’s like magic!

So getting back to Q.17, when we see an assumption question – especially a short, sweet one like this – and it only mentions three terms – health, happiness, and money – the right answer is going to tie together the two terms that only appear once – money and happiness. And it’s going to have a “should” statement, because there’s one in the conclusion, and it didn’t come from the passage, so it must have come from the assumption. Those two things alone – which can be determined at a glance, with no diagramming – guarantee that the only answer that *possibly* be correct is (A).

Hope this helps…drop a reply if you could use clarification on any of it; I know I dropped a lot in here.