Reply To: Prep Test #62

July 18, 2016 at 1:54 pm #2264

Question number 8 really illustrates the importance of identifying the conclusion and focusing on it on LR questions. On this question, the conclusion is that it exaggerates the risk to say explorers are unlikely to survive the trip. Which is another way of saying that they’re likely to survive the trip.

The evidence for this is that they’re likely to survive each individual stage (last sentence), which in turn is supported by the information about the backup system.

And that’s the groundwork for (A), the part-to-whole fallacy. Let’s break down the general terms of (A) and see how they match up to the specific terms in the passage: The problem is that the argument infers (concludes) that something (it is safe) is true of a whole (the trip) merely from the fact that it is true of each of the parts (stages).

The evidence is about the stages; they’re safe. But the trip is composed of multiple stages on a long trip. A single stage is not a trip (or as Mike would say, a piece is not a puzzle). It only takes one stage to go wrong to kill everyone. Analogously, let’s say you’re at a blackjack table, and a crazy guy pulls a gun on you. He says, “If the next card off the top of the deck is the 2 of diamonds, I’m going to kill you; otherwise I’ll leave.” For the sake of this analogy, let’s say you believe him. ok, you’d probably be terrified, but some small part of your brain would be telling the rest of you that you should feel pretty safe; a deck of cards has 52 options, so there’s a better than 98% change that you’re going to be fine. That’s a stage – drawing one card.

Now let’s say he says, “I’m going to pull a card off the top of the deck, and we’re going to do it again 20 more times, and if any of the cards is the 2 of diamonds, you’re dead.” Now you’re feeling not quite so safe. If a nonzero amount of danger occurs repeatedly, at some point, the whole operation is in serious jeopardy, even if the individual risks are small.

So what’s wrong with the other answers that tempted you? Let’s start with (B). “Infers” is synonymous with “concludes.” (B) misstates the passage – the passage doesn’t conclude that something (a fatal accident) CANNOT happen; it concludes that it’s an exaggeration to say that it probably will happen. The passage writer is saying it’s *unlikely*, not *impossible*. That may strike you as a subtle distinction, but those sorts of fine distinctions and language parsing are actually some of the only ways in which the LSAT bears any resemblance to law school. And the difference IS clear, if you look for it – (B) is too strong for what the passage actually concludes.

(D) is similar; it’s too strong. The passage writer doesn’t suggest that the backup system is CERTAIN TO (“will”) work; instead, the assertion is that the system makes a fatal catastrophe “quite unlikely.”

But if you identify and focus on the conclusion, you should be looking for an answer choice like (A). What is the conclusion about? The trip – it’s safe. What is the evidence about? The stages – they’re safe. As always (on flaw questions), there’s a mismatch between the premises and the conclusion. In this case, it’s the part to whole fallacy – taking evidence about the part, and drawing a conclusion about the whole.

#16 illustrates something that more commonly shows up on flaw questions, but you should always been looking for it, because it’s extremely common in the LR section. The premises give us a correlation, but the conclusion asserts cause and effect. Notice that saying that snoring “can damage the throat” is clear cause/effect language – the snoring is the cause, and the throat abnormalities are the effect. But the premises don’t tell you that’s the case. Don’t just identify the conclusion; find its contrast with the premises. Correlation does not equal causation.

Anytime a passage on the LSAT gives you a conclusion that A causes B, you should *immediately* think of the two most common alternatives – maybe they got it backward, that is, maybe B caused A. Or maybe A and B are both effects, and something else is the cause. In other words, maybe C caused A and B. So here, we have:

S –> TA (snoring causes throat abnormalities). From my preceding paragraph, you should immediately think “Maybe they got it backward; maybe the throat abnormalities cause people to snore.” (E) says that’s not the case – it does what commonly happens in strengthen questions; it eliminates a possible alternate explanation. And when you eliminate a possible alternate explanation, you strengthen the argument for the actual explanation.

Here’s another way of looking at it. Let’s say you’re a scientist, and you notice this correlation between throat abnormalities and snoring. You think that snoring causes the throat abnormalities (like the passage says), but you’re not sure. You’d say it’s:

60% snoring causes throat abnormalities
30% throat abnormalities cause snoring
10% something else.

You conclude that snoring causes throat abnormalities, but you’re not SURE. Then one of your other scientist friends comes along and says, “Hey, I’ve just proven that the throat abnormalities don’t cause snorting” (answer choice (E)). Now you have to reassess your estimate. That 30% is no longer possible, so it gets distributed between the other possibilities. Now, maybe it’s:

85% snoring causes throat abnormalities
15% something else
0% throat abnormalities cause snorting (if (E) is true)

Your conclusion just got stronger – it went from 60% to 85%. ANYTIME a possible alternate explanation is eliminated, the conclusion in the passage (or the argument in the passage, if you prefer) gets stronger. When the conclusion is “A causes B,” the passage is suggesting two possible alternatives for you to consider: Maybe B causes A, and maybe C causes both A & B. Most of the time, on this type of argument, the right answer will revolve around one of those possibilities.

Hope this helps.

Go Bruins!