May 27, 2017 at 5:51 am #3104
Assumptions are taken as “leaps” in arguments but are all assumptions “leaps”?
Are leaps always bad(incorrect)?
I am wondering whether some assumptions can be correct and legitimate. Assumptions are unstated premises but just because they are unstated doesnt mean they are leaps?
The incorrect assumptions are, “taken for granted” but can some correct assumptions also be taken for granted?
Thank you so much in advance. I am struggling with this concept..!
May 27, 2017 at 7:56 am #3105
I wanted to add on to my jumbled questions above.
The LR necessary assumption questions ask:
The argument above depends on which of the following?
**does this mean that the argument above is flawed BECAUSE the assumption is not stated?
Is it possible for the correct answer choice to be a false assumption?
Does LR either ask for assumption flaws either because the correct assumption is unstated OR because the assumption itself is false (“takes for granted)?
Thank you so much. I was working on Chapter 7 flaw drills when I got confused about the whole takes for granted concept!
May 27, 2017 at 5:29 pm #3106LSAT DanParticipant
An assumption can be either true or false, but for LSAT purposes, it doesn’t really matter. “Logical reasoning” is, essentially, the ability to determine whether conclusions follow logically from premises, whether those premises are stated or unstated (assumed). For instance:
To get into law school, one must do well on the LSAT. Therefore, one needs to study in order to get into law school.
The argument takes for granted which of the following:
The answer, of course, going to be something like “It is necessary to study to do well on the LSAT.” It’s totally irrelevant to the question whether that unstated is “correct” as a matter of fact or not. It’s a “leap” in that it’s a necessary component of the argument – if it’s not true, the argument falls apart. But is it correct? It doesn’t really matter. What does matter is your ability to recognize it as a critical step between the stated premises and the conclusion.
I’m not sure exactly what you mean by your last question, but basically, assumption questions care about one of two things, depending on which type of assumption question it is –
1) In a sufficient assumption question, the assumption, IF IT’S TRUE, gets you to the conclusion.
2) In a necessary assumption, the absence assumption, would kill the argument. In other words, IF IT’S FALSE, the argument doesn’t work anymore. This is also true for “general assumption” questions, i.e. “The argument assumes which of the following”
Whether the statement is “actually” true or false doesn’t really matter; you’re always just analyzing them hypothetically. “If (B) is true, would that guarantee the conclusion?” or “If (D) were false, would that kill the argument?”
Note that on a sufficient assumption question, you don’t care at all about what would happen if the argument were false. On a necessary assumption question, you don’t care at all about what would happen if the answer choice were true. Because knowing that something is a sufficient assumption doesn’t tell you anything about whether it’s necessary, and vice versa.
There’s a bit of a fine line between flaw questions and assumption questions, and in reality, it doesn’t matter too much. What about the possibility that you can do well on the LSAT without studying (my earlier example)? If it never occurred to me, technically, I’ve probably committed a flaw. If I considered it and disregarded it, I’m making an assumption. But either way, if it’s on an LSAT question, getting the question right will rest on the same thing, whether it’s a flaw question or an assumption question – recognizing that according to the passage, it’s necessary to study to do well on the LSAT. If you catch that, you’re going to get the question right. Of course, on the actual LSAT, the relationship is going to be hidden a little more than in my example. That’s what the LR section is all about – using complex subject matter to obscure fairly simple logical relationships.
Hope this helps.
May 27, 2017 at 6:15 pm #3107
Dear LSAT Dan,
Thank you so, so much for the great clarification! I will refer to your response from time to time whenever I get confused about assumptions again. One thing I am wondering about is how in the LSAT Trainer, we are told (if I understood correctly) to view all LR arguments as “flawed arguments”, and that our approach should be “why doesn’t the support justify the conclusion?”
Then, in the case of necessary assumption questions, should I also immediately view the arguments as flawed?
In your example, “To get into law school, one must do well on the LSAT. Therefore, one needs to study in order to get into law school.”, should I approach this argument as a flawed one and ask, “why doesn’t the support prove the conclusion?”. Is recognizing whether an argument is flawed not helpful in answering necessary assumption questions?
I am afraid that I may be over-stepping the fine line between assumption and flaw questions by thinking this way. Thank you so much, once again!!
May 28, 2017 at 11:53 am #3108LSAT DanParticipant
I think the distinction here may just be one of semantics. I would call the arguments “potentially” flawed, or alternatively, “incomplete.” However, by those terms, I’m confident that I mean exactly what Mike means when he says “flawed” (confident because Mike and I have spend many hours discussing the LSAT). The reason I emphasize the distinction is because I think it will be most helpful to you to be clear. To call an argument “flawed” might suggest that it’s a bad argument, or one that leads to a factually incorrect conclusion. But in the case of assumption-based argument (in LSAT-speak, one that “takes for granted” or “fails to consider” something), that’s not necessarily the case. For instance, to get back to my example, the argument is “potentially flawed” in that it may be the case that some people can do well on the LSAT without studying. Or it’s “incomplete” in that it didn’t explicitly state that premise. But on the other hand, it could be that I have enough experience and knowledge to make that determination, and my analysis is factually correct, in which case it might be misleading to called it “flawed” in lay terminology. But yes, as Mike would suggest, it’s “flawed” in strict logic terminology in that the premises IN AND OF THEMSELVES don’t get you all the way to the conclusion.
I just don’t want you to have the impression that assumption-based arguments lead to bad conclusions. They don’t, at least not necessarily. What they lead to are not-completely-justified conclusions.
Even though it’s an imperfect argument when there’s a missing premise, it’s not “flawed” per se in the way that an argument like “All cats are mammals. Fluffy is a mammal. Therefore, Fluffy is a cat” is flawed. Here, we have a clear misunderstanding of the relationship between cats and mammals, and the route between the premises and the conclusion isn’t just incomplete; it’s flat-out wrong.
As I tried to suggest in my original response, though, the distinction on assumption questions isn’t really critical. You don’t have to worry about overstepping the line, because if you understand what’s missing from the argument, you’re going to get the question right whether it’s an assumption question or a flaw question. It’s not really about the question type here; it’s about the argument structure. The real question is what way of looking at it is the most helpful to you. In your original post, it sounded like you had some confusion through sensing (correctly) that an assumption can be ACCURATE, and that’s what it seems like you original question was asking, and why I was trying to elaborate a bit. Based on what you’ve been asking and what you seem to understand, maybe the simplest way I’d try to wrap it up would be something like this –
1) An assumption can be correct, and it can be justified, so it’s not “flawed” in the sense that it’s necessarily factually wrong.
2) BUT, an argument that relies on an assumption is at the very least incomplete; there’s always that degree of uncertainty. IS the assumption, in fact, true?
3) For LSAT purposes, that answer to the question in 2), above, doesn’t really matter – the (at least POTENTIAL) problem with the argument is the missing piece. If you recognize and focus on that, you’ll get the question right, whether it’s an assumption question or a flaw question.
The “degree of uncertainty” I’m talking about above is related to what Hume called “The Problem of Induction.” Conclusions based on observation are always at least potentially wrong. Take these two situations, for instance:
1) An alien lands on earth. The next morning, the alien sees the sun rise in the east and set in the west. This happens ten more times, and the alien concludes that on earth, the sun always rises in the east and sets in the west.
2) An alien lands on earth and finds someone teach him/her/it about how we record time on earth. It’s March, and the alien learns that there are 31 days in March. Then the alien learns that there are 30 days in April. For 9 more months (the same number of observations in 1)), the alien finds that there are 30 or 31 days in each month. The alient concludes that all months on earth have at least 30 days. Then it becomes February. OOPS. That’s Hume’s “problem of induction.”
There’s always the potential that it’s 2). That there’s a student I haven’t met who scores well on the LSAT without studying, for instance, in my example. But again, as long as you’re aware that this MIGHT be the case, it doesn’t matter (on the LSAT) whether it actually IS the case. You just have to identify the gap in the argument.
May 28, 2017 at 3:18 pm #3109
Dear LSAT Dan,
Once again, I am deeply grateful for your kind and comprehensive clarification. I’d be so lost on assumptions without your help! I now have a clear understanding of how to approach the assumption questions. Thank you for informing of the correct, complete, and effective way to solve the assumption questions! Your thorough explanation clarified areas that I didn’t know that I didn’t understand. I am very encouraged by your help and inspired by the LSAT Trainer to continue on this tough yet rewarding journey studying the LSAT. I honestly don’t know how to thank you enough!
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