LR Question 23 Explanation, by LSATHacks
QUESTION TEXT: Company president: Almost every really successful product…
QUESTION TYPE: Flawed Parallel Reasoning
CONCLUSION: The Vegetaste Burger will probably be very successful.
REASONING:
- Successful product ➞ Massive ad campaign
- Vegetaste will have a massive ad campaign
ANALYSIS: The president gives us a single conditional statement, then tells us that Vegetaste meets the necessary condition of that statement.
(Technically it’s not a conditional, because it says “almost all”. But drawing it as a conditional simplifies the question).
A necessary condition never proves anything. It’s as if I said that because something has a tail, it’s a cat.
So we need another argument with one conditional statement and the necessary condition as evidence. Then the argument should incorrectly conclude the sufficient condition.
___________
- This is a silly argument. It’s like saying “Barack Obama must be the president of some other country, because most people in America are not president”. But this is a flaw of numbers, not the flaw made in the stimulus.
- We can say that if you work at Coderight, you probably have ten years experience. Donna will probably meet this sufficient condition, but the argument concludes that she will certainly have the experience. So this is a bad argument. But it doesn’t reverse sufficient and necessary.
- This is actually a pretty good argument. If 95% of Acme’s workers are factory workers, and 95% of them oppose the merger, then at least 90.25% of Acme’s workers oppose the merger.
- CORRECT. This mirrors the structure:
President ➞ Ph.D
Robert has a Ph.D. We can’t expect Robert to become president just because he meets the necessary condition. Maybe Robert is a down-on-his-luck hobo with a Ph.D. - This is a pretty good argument. Evidence from the past can let us make probabilistic predictions about the future.
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Hi there,
I have a question about the validity of (C).
The first time I did this question, I thought (C) was a valid argument. But after revisiting it, I’m now considering that (C) might actually be invalid, even though this doesn’t change the fact that it clearly has a different flaw from the one in the stimulus.
Here’s my thought process:
1. Since “almost all” is a vague concept, I first tried replacing it with “most” to see if that helps clarify the argument.
Suppose there are 100 workers in the company. If the premise is: Most workers in this company are factory workers, and most factory workers in the company oppose the merger, I don’t think we can conclude that most workers oppose the merger. This is because we can only be certain that “at least” 51 workers in the company are factory workers, and at least 27 factory workers in the company oppose the merger?
It’s possible that every worker in the company who isn’t a factory worker supports (or doesn’t oppose) the merger. Since we can only be certain that 27 factory workers oppose the merger, we can’t conclude that “most” workers (51 or more) in the company oppose the merger?
2. Next, I consider the term “almost all.” “Almost all” is vague, and it’s difficult to determine what percentage it represents. However, I think the argument would be invalid no matter what percentage threshold we assign to “almost all” (as long as our threshold is consistent).
For example, if we use 91% as the threshold for “almost all,” then we can only be certain that “at least” 91 workers in the company are factory workers, and at least 83 factory workers oppose the merger.
It is possible that every worker in the company who isn’t a factory worker supports (or doesn’t oppose) the merger, so we still can’t conclude that “almost all” (91 or more) of the workers in the company oppose the merger.
3. One might argue that 91% is not the correct threshold for “almost all.” But as reasoned above, regardless of the percentage we assign to “almost all,” the argument will still be invalid as long as we define “almost all” consistently. In fact, the lower the percentage we assign to “almost all,” the greater the gap between “the number of workers we are certain to oppose the merger” and “the number required to conclude that ‘almost all’ of the workers oppose the merger.”
Sorry for the lengthy question! I hope it makes sense.
I’m a little confused.
The conclusion of B and the conclusion of the stimulus both seem to indicate probability. “the burger will “probably” be very successful and Donna will “probably” be hired. What am I missing here?
Also regarding your explanation of E..isn’t making a prediction about the future from past evidence a temporal flaw?
Thanks!
(B)’s argument is slightly tricky. On first read, it might seem like the conclusion is “Donna will probably be hired as a programmer by Coderight”. But if you look more closely, the argument is actually:
(1) Every programmer who works for Coderight has at least ten years experience
(2) Donna will probably be hired as a programmer by Coderight
Therefore, Donna has at least 10 years experience as a programmer.
That’s why the conclusion structure doesn’t match that of the stimulus.
As for (E), saying something will certainly happen because it’s happened in the past is a flaw in reasoning. But, to conclude that something will probably happen since there’s a lot of past evidence of it happening is actually a pretty good argument.
I am still confused by answer choice B.
It’s my understand that it’s saying
If Coderight –> almost all 10 year exp (“almost every” is said in the stimulus)
Donna has 10 years. That is the necessary condition. And it reverses back to being hired at Coderight.
Can you please explain to me why this doesn’t work? And why it’s different than D?
It’s because B switched from probably to certainty. Whereas the stimulus concluded “probably”.
Also, another issue with B is the time issue. The coders might not have had ten years experience *when they were hired*. That time issue isn’t present in the stimulus.
Ah thank you!