## Assumption of Causal statement

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borntokill

Posts: 23
Joined: Wed Jun 03, 2009 8:26 am

### Assumption of Causal statement

Causal statements in LR always give me headache.
I remember reading somewhere in the LR bible that says something like when an author claims a cuasality, the author aways assumes the effect can only be produced by the cause and the cause always produce the effect.
Today, in a LR question, the causal conclusion is "A can cause B, because more As are Bs than Cs are Bs" and incorrect answer includes Most A are not B, and Most Bs are not A. If I had followed the bible instructions, then both these wrong choices would have been attractive because both attack the assumption that the cause is the only cause / the effect is the only effect.
So does this mean the Bible's law on assumption behind causality could only apply when the author claim the causality with one hundred percent certainty?

aether

Posts: 57
Joined: Wed Dec 09, 2009 12:25 am

### Re: Assumption of Causal statement

borntokill wrote:the LR bible that says something like when an author claims a cuasality, the author aways assumes the effect can only be produced by the cause
Wrong.
and the cause always produce the effect.
Um... not always, no.

Causality is actually very simple. You're just confusing yourself by misremembering the LR bible! Try this sentence: "when it rains, the ground gets wet." In formal logic: raining --> wet ground.

This is causality, because the rain actually causes the ground to be wet. Wet ground is a direct effect of rain.

However the reverse statement (wet ground --> raining) would be a logical fallacy. Lots of things could cause wet ground: sprinklers, a broken fire hydrant, melting snow, etc. That's why your first statement above is wrong. Even with a valid causality relationship, you cannot assume that the effect is produced ONLY by the specified cause.

Also note that 100% reliability is not required. Consider this statement: "smoking causes lung cancer." It's a true statement... but does that mean that EVERY smoker develops lung cancer? No. It means that smokers are more likely to develop lung cancer, and the smoking is the reason. Causality might give you 100% certainty sometimes, but it won't always.

The most important thing is to distinguish causation from correlation. "Buying cigarettes causes lung cancer" is a false statement -- that is correlation, not causation. While people who buy cigarettes do get lung cancer more often, it's because both things are caused by a third factor: actually smoking the cigarettes. Smokers are more likely to buy cigarettes, and smokers are more likely to get lung cancer. The causal factor is the smoking, not the purchase.

Clear as mud?

cubswin

Posts: 617
Joined: Mon May 25, 2009 4:40 pm

### Re: Assumption of Causal statement

aether wrote:
borntokill wrote:the LR bible that says something like when an author claims a cuasality, the author aways assumes the effect can only be produced by the cause
Wrong.
and the cause always produce the effect.
Um... not always, no.

From p. 211: "When an LSAT speaker concludes that one occurence caused another, that speaker also assumes that the stated cause is the only possible cause of the effect and that consequently the stated cause will always produce the effect."

aether

Posts: 57
Joined: Wed Dec 09, 2009 12:25 am

### Re: Assumption of Causal statement

cubswin wrote:From p. 211: "When an LSAT speaker concludes that one occurence caused another, that speaker also assumes that the stated cause is the only possible cause of the effect and that consequently the stated cause will always produce the effect."

What is the context of that quote, Cubs? Is the bible suggesting that this is the common fallacy in LSAT reasoning questions, and you should watch out for it? Or are they saying those statements are actually true?
Last edited by aether on Thu Dec 31, 2009 3:12 pm, edited 2 times in total.

cubswin

Posts: 617
Joined: Mon May 25, 2009 4:40 pm

### Re: Assumption of Causal statement

aether wrote:
cubswin wrote:From p. 211: "When an LSAT speaker concludes that one occurence caused another, that speaker also assumes that the stated cause is the only possible cause of the effect and that consequently the stated cause will always produce the effect."

What is the context of that quote, Cubs? Is the bible suggesting that this is the common fallacy in LSAT reasoning questions, and you should watch out for it? Or are they saying those statements are actually true?

No. They are claiming that when you see an argument on the LSAT like the following:

Brenda: I ate a cheese sandwich this morning. My ovaries exploded this afternoon. Therefore, the cheese sandwich made my ovaries explode.

That the author has "weighed and considered every possible alternative and then rejected each one... Thus, in every argument with a causal conclusion that appears on the LSAT, the speaker believes that the stated cause is in fact the only cause and all other theoretically possible causes are not, in fact, actual causes." p. 203-204

skynet

Posts: 134
Joined: Fri Dec 18, 2009 10:40 am

### Re: Assumption of Causal statement

I'm assuming that you are dealing with a necessary assumption question. If so, then the "most's" in the answer choice make it incorrect, because the argument does not require assuming any particular quantities. What it requires assuming is that the given relative quantities can only be explained by positing a causal connection.

Try not to get too caught up in any hard-and fast rule like the one you cited. The problem with any argument is that the premises given are not sufficient to guarantee that the conclusion is true. Instead of memorizing rules, practice identifying why the conclusion might be false despite the premises being true.

borntokill

Posts: 23
Joined: Wed Jun 03, 2009 8:26 am

### Re: Assumption of Causal statement

skynet wrote:I'm assuming that you are dealing with a necessary assumption question. If so, then the "most's" in the answer choice make it incorrect, because the argument does not require assuming any particular quantities. What it requires assuming is that the given relative quantities can only be explained by positing a causal connection.

no, it's a weakening question. The two wrong choices with "most" could both weaken the causal relationship.
(I suppose we all agree that "A causes B" could be weakened by most As are not Bs, or most Bs are not As)

The stimulus is More As are Bs than Cs are Bs. Thus, A can causes B.

skynet wrote:Try not to get too caught up in any hard-and fast rule like the one you cited. The problem with any argument is that the premises given are not sufficient to guarantee that the conclusion is true. Instead of memorizing rules, practice identifying why the conclusion might be false despite the premises being true.

agree with the second part.

borntokill

Posts: 23
Joined: Wed Jun 03, 2009 8:26 am

### Re: Assumption of Causal statement

aether wrote:
borntokill wrote:the LR bible that says something like when an author claims a cuasality, the author aways assumes the effect can only be produced by the cause
Wrong.
and the cause always produce the effect.
Um... not always, no.

Causality is actually very simple. You're just confusing yourself by misremembering the LR bible! Try this sentence: "when it rains, the ground gets wet." In formal logic: raining --> wet ground.

"when it rains, the ground gets wet." sounds more like conditional statement. I don't think this is a causal statement

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