Logical Reasoning Brain Teaser Forum

[testmachine45]

Pretzels can cause cavities. Interestingly, the longer that a pretzel remains in contact with the teeth when it is being eaten, the greater the likelihood that a cavity will result. What is true of prestzels in this regard is also true of caramels. Therefore, since caramels dissolve more quickly in the mouth than pretzels do, eating a caramel is less likely to result in a cavity than eating a pretzel is.

The reasoning in the argument is vulnerable to criticism on the grounds that the argument:

A)treats a correlation that holds within individual categories as thereby holding across categories as well.


I don't understand why the answer is A. What are the individual categories and what does it mean to be 'across a category?' This is not an unambiguous commonly used part of our vernacular(thus having a common meaning) as far as I know.

Edit: DEC 94 LSAT, LR 1, #20

[bk1]

Remove the text of the question and replace it with a reference to PT #, Sec #, Q #.

[sayruss11]

The evidence sites that the longer a PRETZEL remains in contact with the teeth, the greater the likelihood that a cavity will result and then based on this makes a conclusion comparing pretzels to caramels. This is flawed because the evidence is relative to the category of pretzels and generally you shouldn't make a conclusion about one category (pretzels) relative to another category (caramels) based only on evidence from one of the categories, but thats exactly what the argument does.

[testmachine45]

NICE. TY.

[bk1]

NICE. TY.

You still haven't removed the text you copied from the PT itself. You should do that.

[testmachine45]

I did not copy from the PT itself.

[fosterp]

Its because comparing a pretzel that contacts a tooth for 2 seconds to a pretzel that contacts a tooth for 4 seconds is not the same as comparing a pretzel and caramel.

(arbitrary numbers here)

lets say 3 seconds of contact with pretzel is 10% chance of cavity

and 6 seconds is a 20% chance of cavity.

Then we say this increasing likelyhood is the same of caramel.

1 seconds of caramel = 40% chance of cavity

2 seconds of caramel = 80% chance of cavity

The caramel is having less contact, yet a higher chance of cavity. The premise is taken to be true yet comes to a different conclusion. This is because the correlation within a category (pretzel) does not hold across to a different category (pretzel to caramel).

[sayruss11]

I did not copy from the PT itself.

ummm "copy" as in "use the exact words". just erase the text from the original post. and btw its PT 13 S2 Q20