What flawed reasoning is this?

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apollo13
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What flawed reasoning is this?

Postby apollo13 » Sun Jan 27, 2013 1:52 am

I was debating with my friend over the weekend on this topic, I notice flawed reasoning in my argument. What do you think it is?

Premise: Diana’s friend has cancer and is on leave of absence.

My Argument: People with cancer, namely Diana’s friend, have difficult time studying because of the pain that they go through. From this, normal people like us who are more able than they are, should have no reason not to study hard.

Diana’s argument: You’re wrong, you cannot compare peoples’ capacities to pain. People have different measurement of how they conceive pain.

I'm thinking its "Errors of composition and division"
:An error of composition occurs when the author attributes a characteristics of part of the group as a whole or to each member of the group. “presumes, without providing justification that what is true of a whole must also be true of its constituent parts.”

What do you think the flawed reasoning is? and How can I weaken Diana's argument?

nugnoy
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Joined: Mon Oct 15, 2012 10:19 pm

Re: What flawed reasoning is this?

Postby nugnoy » Sun Jan 27, 2013 2:23 am

lol...From LSAT student's point of view there are leaps, leaps everywhere.

I CAN tell you that it's NOT error of composition and division.

Error of composition is: each of the parts of my ferrari is cheap. So my ferrari is cheap.
Error of division is: America is a wealthy nation. So every American is wealthy.

In Diana's case it'd have to be something like
Humanity as a group has multiple measurements of how it measures pain.
So each individual has multiple measurements of how he/she measures pain.

I think I have to question the premises, but I'm not allowed to.

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apollo13
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Re: What flawed reasoning is this?

Postby apollo13 » Sun Jan 27, 2013 2:26 am

Well, I am assuming that just because someone has a cancer, they are all physically unable to do stuff, including Diana's friend.

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Shmoopy
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Re: What flawed reasoning is this?

Postby Shmoopy » Sun Jan 27, 2013 2:30 am

What does "no reason not to study hard" have anything to do with it? I don't think there is a named fallacy here -- the problem is just that the premise doesn't give any reason for the leave of absence. Maybe the pain makes it hard to concentrate, maybe the chemo drugs make it hard to concentrate, maybe treatment takes up too much time, maybe the emotional stress of cancer negatively affects work... There is nothing in the premise that makes a leap to statements about what people who don't have cancer should be doing.

Kellanj
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Joined: Sun Jan 13, 2013 11:39 am

Re: What flawed reasoning is this?

Postby Kellanj » Sun Jan 27, 2013 11:39 am

If you look at your argument in terms of an if, then statement, then you're saying that if someone has cancer, then they will have a difficult time studying. You then go onto say, essentially that if you do not have cancer, then you should not have a difficult time studying, and there is no reason not to study hard because of this.

First off, there is a mistaken negation in the first part of your argument. Instead of forming the contrapositive of your claim: if someone does not have a difficult time studying, then they do not have cancer.

You mistakingly negate both parts of your if, then statement. There are a lot of reasons why someone might have a difficult time studying even if they don't have cancer.

The last part of your argument; there is no reason not to study hard if one doesn't have cancer, is, like some of the other posters said a leap in logic. There's no support for that. There could be a million reasons to not study hard, and all Dianna has to do is point out one to weaken your argument.

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A → B ⊨ ¬B → ¬A
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Re: What flawed reasoning is this?

Postby A → B ⊨ ¬B → ¬A » Sun Jan 27, 2013 12:06 pm

apollo13 wrote:My Argument: People with cancer, namely Diana’s friend, have difficult time studying because of the pain that they go through. From this, normal people like us who are more able than they are, should have no reason not to study hard.


I think you are denying the antecedent twice.
The first sentence: (Cancer -> Pain) and (Pain -> Difficult to study hard), so (Cancer -> Difficult to study hard) [valid]
therefore
The second sentence: (~Cancer -> ~Pain) [invalid] and (~Pain -> ~Difficult to study hard) [invalid], so (~Cancer -> ~Difficult to study hard)




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