#22 - Wirth: All efforts to identify a gene responsible

[Luke Haqq]

Hi ashpine17!

Answer choice (D) states that C's criticism of W's argument is that "It disallows in principle any evidence that would disconfirm its conclusion." A circular argument can do this. Effectively, this is saying that W will interpret all evidence to support W's position and won't consider the possibility of contrary evidence. We don't know that W is doing this. Rather, W seems to be reaching an incorrect conclusion based on the premises.

Namely, W thinks that the failure of researchers to find a specific gene that causes manic-depression establishes that people are not genetically predisposed to manic-depression. C points out that a single gene isn't the only possible cause, and rather that the interaction of several genes might produce a genetic predisposition to manic-depression. This is why (A) accurately describes C's criticism of W's argument: "It presupposes only one possibility where more than one exists."

[teddykim100]

Hello,

picking up off the above - is D wrong simply because W doesn't disallow any EVIDENCE, but rather disallows all conclusions aka CLAIMS?

[srusty]

Hello,

picking up off the above - is D wrong simply because W doesn't disallow any EVIDENCE, but rather disallows all conclusions aka CLAIMS?

Hi Teddy,

Answer Choice (D), when boiled down to simpler language, says that Chang is taking issue with the evidence that is being used by Wirth, because Wirth is disallowing evidence that would go against their conclusion. However, the stimulus has Chang clearly state that "I do not dispute your evidence."

So, Chang's criticism of Wirth's argument is not about the evidence, because Chang says so themselves. For that reason, answer choice (D) is wrong.

Hope that helps!

[Davepix]

I see it as D
Therefore, if these researchers are right, any claim that some people are genetically predisposed to manic depression is simply false.

Chang disagrees with the above conclusion, the opposite conclusion results in as claimed false: no one is genetically predisposed to manic depression

[Davepix]

Additionally, they agree on evidence, not the conclusion and nowhere does Wirth consider multiple genes, only that a gene responsible has not been identified

[Jeff Wren]

Hi Davepix,

I'm not sure that I completely understand your comments, but hopefully this explanation will be helpful.

Answer D is describing a type of circular argument in which there would be no way to disprove it. This is not the flaw in Wirth's argument. In fact, the additional evidence that Chang does bring up (evidence that a set of genes produce a pre-disposition to manic-depression) does in fact disconfirm Wirth's conclusion. In other words, the flaw in Wirth's argument isn't that it is impossible to disprove (like a circular argument), but that Wirth fails to consider another possible way that genes could pre-dispose one to manic-depression. The flaw in Wirth's argument boils down to failing to consider another possible explanation, which is described in Answer A.