by ohthatpatrick Thu Jun 06, 2019 3:23 pm
Yeah, I feel your pain.
(E) is totally sensible and plays to our common sense, but it's not logically necessary for there to be a causal relationship there.
If we negate (E), we're just saying
"their inability to consider the consequences is not due to their strong feelings about the law".
Okay, but this negation still admits that they have an inability to consider consequences. By the rule we're given in the first sentence, knowing that they have an inability to consider consequences means that they are unable to enact laws that benefit constituents. So the author still reaches her conclusion.
Hence, the negation of (E) didn't weaken.
Meanwhile, when you negate (D), it's saying
"Legislators with strong feelings about a law DO consider its consequences".
That's weakening the argument, because now we can't use that conditional rule in the first sentence to derive the conclusion.
If you're struggling to think of a world in which (D) exists but (E) doesn't, make this will help:
When the legislators present legislation in polemical terms, the media will cover it in polemical terms, and so the public will understand it in polemical terms. When the public hears something extreme like "Obamacare = death panels", they flood their representatives with calls and convince the legislators that they better vote against this law.
The legislators, fearing for their political future, obey the wishes of their constituents and so they don't bother to consider the consequences of the legislation.
That's a world in which "legislators considering a law do not consider the consequences" but "their inability to consider the consequences is NOT due to their own strong feelings about that law".