Q7

[StephanieK821]

The forum wouldn't allow me to create a topic location for Passage 1 so I am posting here - can someone help explain why (E) is a better answer choice than (A)? I eliminated B, C, and D pretty quickly, but I ultimately eliminated E as well because I thought that the detail that the antibacterial drug was effective in reversing the onset was not as strong in weakening the connection of the prion causing CJD.

[Laura Damone]

When we undermine a causal claim, we should always think first and foremost about providing an alternate cause. A mentions a viral infection. That could be an alternate cause. But if you dig a little deeper, you'll see that the virus causes some symptoms that closely resemble those of CJD, but never does A say that the virus could cause CJD itself.

E, on the other hand, shows that an antibacterial drug is reversing the onset of CJD itself. It's not controlling the symptoms, or similar symptoms; it's actually reversing the condition. If an antibacterial drug is reversing the condition, that implies that the cause of the condition is bacterial. Boom - alternate cause!

Implicit causality like this can be tricky to spot. On the LSAT, it's often presented in this format: We stopped doing X and Y stopped happening. That implies that X was a probably cause of Y.

Hope this helps!

[CharlesT757]

I now see why (A) is wrong. Just because something resembles another thing DOES NOT mean that something causes another thing.

For some reason, answer (C) was attractive to me because the answer stated that prions were linked to another condition that does NOT affect the brain or central nervous system. My thought process was that CJD is affected though the plaque of prions into the brain/nervous system. If prions did NOT affect this brain or central nervous system, wouldn't that debunk the causation claim? Answer (C) still wouldn't show why prions don't cause CJD. Answer (C) is just saying prions cause even more problems.

[Laura Damone]

Exactly. Just because prions cause problems OTHER than brain and central nervous conditions doesn't undermine the claim that they do indeed cause CJD. This is a classic causal trap!

To undermine the claim that A causes B, you can't show that A causes C, because it's possible that A could cause both