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General questions relating to LSAT Logical Reasoning.
 yongjook
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#20433
Hi,

I would like to know if there is a relationship between Premise & conclusion and Sufficient & necessary.

Premise gives the reasons why the conclusion should be accepted, then could this mean that premise could be necessary?

Is it correct to think premise&conclusion is mainly to identify conclusion of the passage while sufficient & necessary is just to find a logical statement?

I'm just confused what to look for first when solving some of these questions. I usually don't think of the three, i.e. Premise & conclusion, Sufficient & necessary, and Cause & Effect, but when I try to pick out the identifiers, I get confused which one is present in the passage.

Hmm. I'm not sure what i'm even asking, but any answer might help my mind click.

Thank you
 Nikki Siclunov
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#20481
Hi yongjook,

Premises and conclusions are argument parts: they designate the function of claims according to whether they support, or are supported by, other claims. By contrast, sufficient and necessary conditions are elements of conditional reasoning: these labels designate the function of claims according to whether their occurrence is sufficient or necessary for other claims to be true. Conceptually, the two distinctions - premise vs. conclusion and sufficient vs. necessary - have absolutely nothing in common.

Let me put it another way: conditionality (and causality) are words we use to designate the type of argument. Some arguments are conditional, others are causal. Some are neither, others are both. By contrast, premises and conclusions are constituent parts of every single argument. We cannot have an argument without a conclusion, and we cannot have a conclusion unless we have premises supporting it.

The only conditional relationship that we can say is inherent in the structure of an argument is that between the conclusion of that argument and the assumptions upon which that conclusion is based. Since every argument presupposes the truth of its assumptions, we can represent that conditionality as follows:

Conclusion (valid) :arrow: Assumptions (true)

As far as causal reasoning is concerned, we do see some conceptual overlap between the cause for a given effect and the conclusion of the argument: when the causal relationship is being inferred from a series of observations, the conclusion usually presents the cause for those observations (which function as premises). Then again, there are certain arguments in which the causal relationship is presented as a premise, and should not be questioned.

To sum up, remember this: the labels of "premise" and "conclusion" designate the argumentative purpose (or function) of various claims. By contrast, labels such as "sufficient," "necessary," "cause" and "effect" designate the type of reasoning contained in that argument.

Hope this clears things up!
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 Dave Killoran
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#20489
Hi Yongjook,

I'll throw my half a cent in there as well (only a half cent because I went for a simplified version of what Nikki said :-D ):

Premises and conclusions are the main pieces that make up arguments. Some arguments are of different types, including causal and conditional arguments. This relates to the types of statements included in the premises and conclusions. For example, in a conditional argument, the premises could be a conditional statement, as could the conclusion. Or, some premises and conclusions could just be a condition from a conditional statement. The following is a good example of how a standard two-premises-and-conclusion argument looks when it is conditional:

  • Premise: A :arrow: B (this is a conditional statement)
    Premise: B (this is the negation of the necessary condition from the statement above)

    Conclusion: A (this is the negation of the original sufficient condition from the statement in the premise above)
The indicators you see help tip you off to what you are looking at. If I see the phrase, "is always caused by" in a stimulus, I think to myself that causality is present. But, that phrase could appear in either a premise or a conclusion, and so I have to look for other indicators or clues in order to determine what part of the argument it is in. In this sense, you are like an air traffic controller—you have to spot what appears on the screen and then identify it and track it. Sometimes it's not clear and takes some work, but all these indicators help make the work easier.

Does that help? Please let me know. Thanks!
 yongjook
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#20652
Thank you Dave and Nikki. The explanations helped a lot.

I just want to finalize my thought using a question from 2003 December section 4 question 22 which states:

22. Only a minority of those who engage in political action do so out of a sense of social justice.
Therefore, some people who have a sense of social justice do not engage in political action.

The premise would be the first sentence and the conclusion second sentence and each sentences have conditional statements .
That being said my question is regarding arrows On page 37 Logical Reasoning bible under complex argument sections that point from premise to conclusion. I think my confusion with the conditional reasoning came from these arrows.
My thinking now is that there aren't actual arrows between premise and conclusion like there are between sufficient and necessary. So if I were to diagram the question.

It would be something like:
Premise: social justice -> engage in political action
Conclusion: Sj-> not political action.

Is this the correct way of thinking?
Thank you
 David Boyle
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#20667
yongjook wrote:Thank you Dave and Nikki. The explanations helped a lot.

I just want to finalize my thought using a question from 2003 December section 4 question 22 which states:

22. Only a minority of those who engage in political action do so out of a sense of social justice.
Therefore, some people who have a sense of social justice do not engage in political action.

The premise would be the first sentence and the conclusion second sentence and each sentences have conditional statements .
That being said my question is regarding arrows On page 37 Logical Reasoning bible under complex argument sections that point from premise to conclusion. I think my confusion with the conditional reasoning came from these arrows.
My thinking now is that there aren't actual arrows between premise and conclusion like there are between sufficient and necessary. So if I were to diagram the question.

It would be something like:
Premise: social justice -> engage in political action
Conclusion: Sj-> not political action.

Is this the correct way of thinking?
Thank you
Hello yongjook,

Some explanations of premise-conclusion may draw arrows going upwards, not sideways, from premise to conclusion, to show that premises support conclusions. But they don't have to be arrows: they could be pillows, or anything else showing support! So I wouldn't worry too much about those arrows for now.
As for the rest: diagramming the first sentence of the stimulus might actually be something like

pabsj :arrow: min (if you do political action because of social justice, you're in the minority)

The second sentence might be,

sj :some: slash pa. (some social justice folks do not do political action)

The conclusion is false because, commonsensically, maybe every single person on earth with a sense of social justice does do political action. Maybe everyone else who does political action is paid to do so (e.g., being a paid campaign staffer), for all you know, but again, maybe everybody with a sense of social justice does do political action. Can't disprove it from the stimulus.

Hope this helps,
David
 Richardjh
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#20695
In an argument one expects the claim to be supported with a premise or reason. So premise will be true and will lead to conclusion. And coming on to sufficient and necessary, I can explain it by:
If event A must occur for event B to occur, then we say that A is necessary for B. If event A may cause B but there could be some other cause as well, then we say that A is sufficient to cause B.
 David Boyle
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#20725
Richardjh wrote:In an argument one expects the claim to be supported with a premise or reason. So premise will be true and will lead to conclusion. And coming on to sufficient and necessary, I can explain it by:
If event A must occur for event B to occur, then we say that A is necessary for B. If event A may cause B but there could be some other cause as well, then we say that A is sufficient to cause B.
Hello Richardjh,

A premise may be true and lead to a conclusion, though the premise may need help from other premises. E.g., premises "Joe is an ice cream addict" and "Joe is 5 feet from an ice cream shop" may both be needed to conclude, "It is likely Joe will eat ice cream in the next 5 minutes". If either premise is missing, the conclusion doesn't have much support.
Also, re "If event A may cause B but there could be some other cause as well, then we say that A is sufficient to cause B", I'd rephrase it slightly, as, "If event A always causes B but there could be some other cause as well, then we say that A is sufficient to cause B--even if other causes are also sufficient to cause B."

Hope this helps,
David

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