Doubts about Causality

[miteshsholay]

Here is an excerpt from an article I read on gmat club about causality:
Source : http://gmatclub.com/forum/almost-all-of-us-would-have-heard-of-causal-arguments-and-155034.html

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EXAMPLE 1
Let’s consider a simple example in which the argument says that
Eating sugar leads to obesity.
Can we weaken this statement by saying that
Eating oil leads to obesity.
The answer is No.

MODIFIED EXAMPLE 2
Now, Let’s look at a modified version of our simple example:
If the argument says that
Eating sugar made Jon obese.
Can we weaken my statement by saying that
Eating oil made Jon obese.
The answer here is Yes.
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TAKE AWAYS
1. "X leads/can lead/will lead to Y" allows the possibility of an alternate route, Z, to reach the effect, Y. Therefore, an option statement presenting an alternate route does not weaken this conclusion type.
2. "X led to Y" is presenting a reason (X) for a specific occurrence in the past (Y). An option statement suggesting an alternate cause, Z, which led to Y, creates doubts on the conclusion and thus, weakens the argument.

Are these reasonings correct?
Because I think that in example 1, as per GMAT causality, doesn't the author assume that 'Eating sugar' is the only cause that leads to obesity? And since 'eating oils leads to obesity' presents an alternate cause, should weaken the 'eating sugar leads to obesity' statement?

[RonPurewal]

Because I think that in example 1, as per GMAT causality, doesn't the author assume that 'Eating sugar' is the only cause that leads to obesity?

no, of course not. (if i say running will make me tired, does that imply that nothing else in the whole world will make me tired?)

in one sense, this is just a matter of literal interpretation: the sentence doesn't say (nor does it contain anything that would imply) that the causation is exclusive.

but, MUCH more importantly, real-world common sense should tell you right away that this is not an exclusive statement. because ... well, because it's just obvious, if you live on planet earth with other human beings. you know that people can get fat for lots and lots of different reasons, of which only one is excessive consumption of sugar.

the root cause of the problem here is your thinking that "GMAT causality" is some special animal that's unlike how things work in the real world.
that's exactly the opposite of what's really true: "GMAT causality" is just the same kind of causality that you see in the real world.
(in fact, this is the primary reason why CR is a large component of the test -- because you can't memorize "rules" for it, and must instead use the normal human thought processes that already exist in your head.)

[miteshsholay]

Thanks for the reply Ron. I did think that GMAT causality was something different. I get that I was wrong.

in one sense, this is just a matter of literal interpretation: the sentence doesn't say (nor does it contain anything that would imply) that the causation is exclusive.

But in scenarios where "X led to Y", causation is still exclusive right ?
If yes, then why doesn't real world thinking apply to those scenarios like in the modified example?
Eating sugar made Jon obese.
Eating oil made Jon obese.
Both of them could've made Jon obese.

Please let me know what is wrong with my interpretation. :-(

P.S.: Also I wish there was a Thursday with Ron session on causality :-), but my gmat is only a month away and i guess the topics of next couple of sessions must've already been decided.

[RonPurewal]

when you're talking about one individual or one particular case of something, then competing explanations weaken each other.
they don't necessarily destroy each other, but they certainly do weaken each other somewhat.

e.g.,
gunshots make noise (in general). also, fireworks make noise (in general). neither of these statements weakens the other.

on the other hand, if i hear a particular noise right now and i say, "hey, i think that was a gunshot"... if you say "well, some fireworks just went off", then, yes, that weakens my contention that it was a gunshot.

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most importantly, i would caution you against trying to study this stuff at all.
these are already things you know, just by virtue of everyday common sense; the challenge is just to get to a place where you can apply everyday common sense to the situations described on the test.
if you try to make "rules" for this kind of stuff, you'll actually get worse and worse at it with each "rule" that you try to memorize.

[miteshsholay]

when you're talking about one individual or one particular case of something, then competing explanations weaken each other.
they don't necessarily destroy each other, but they certainly do weaken each other somewhat.

Thanks again Ron.
This one is a great takeaway for me.
I think I can't explain my remaining dilemma without citing the source of my confusion.
Actually the source of this doubt is an OG question.
Posting the question number for reference:

OG Verbal Review 2nd edition CR Q. No 33

The argument is of the form 'X causes Y'
Now even though B is a wrong answer coz the question is a strengthen type , but the official explanation rejects option B, stating that B presents an alternate cause & hence is a weakener. (Z causes Y)

How do you explain this inconsistency?

[miteshsholay]

Ron or other experts,
I am still hung up on this one. Looking forward to your reply.

[RonPurewal]

when you're talking about one individual or one particular case of something, then competing explanations weaken each other.
they don't necessarily destroy each other, but they certainly do weaken each other somewhat.

Thanks again Ron.
This one is a great takeaway for me.
I think I can't explain my remaining dilemma without citing the source of my confusion.
Actually the source of this doubt is an OG question.
Posting the question number for reference:

OG Verbal Review 2nd edition CR Q. No 33

The argument is of the form 'X causes Y'
Now even though B is a wrong answer coz the question is a strengthen type , but the official explanation rejects option B, stating that B presents an alternate cause & hence is a weakener. (Z causes Y)

How do you explain this inconsistency?

I don't understand what the "inconsistency" is here.
This problem refers to one specific type of art (Renaissance oil paintings under similar climate conditions), so the same idea is, in general, a thing.

Two things:

1/
I really don't know how to explain this any further.

More importantly,
2/
I shouldn't try to generalize any further about this, because, if I did, I'd be encouraging entirely the wrong kind of thinking. If you try to formulate "rules" for CR, it will be impossible for you to solve the problems.
You really must use everyday normal human intuition ("common sense") to make the necessary connections in these problems. This is actually why they are on the test -- because it's actually impossible to concoct "rules" that will solve them.
So, the way that you're going about this -- using X's and Y's and Z's and trying to make formulas out of everything -- is actually going to make you worse at CR. Not better.

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[RonPurewal]

In any case, I can give you an analogy, which will hopefully be easier to understand. Don't try to make a "rule"; just think about the situation using your normal common sense.

Sunlight can cause skin cancer.
Exposure to radiation can cause skin cancer.
--> These statements do not weaken each other.

The residents of Plutonia, Arizona, get skin cancer at five times the state-wide rate. The particularly intense sunlight in Plutonia must be to blame for this observation.
--> Here, if I told you...
... Plutonia was built on top of an old nuclear-waste site, which has since been found to emit a kind of radiation that causes skin cancer ...
... then that would weaken the argument above.

Don't try to make a formula for it. Just check it out and make sure it accords with your own common sense.