A
Massive doses of aspirin and vitamins enhance athletic performance.
B
Addictive drugs are just as unnatural as nonaddictive drugs like aspirin and vitamins.
C
Unnecessary deaths and injuries occur in other walks of life besides modern sports.
D
There would be more unnecessary deaths and injuries if it were not for running shoes, boxing gloves, and bodybuilding machines.
E
Taking massive doses of aspirin or vitamins can be physically harmful.
To see how (B) weakens the argument, we need to first understand the assumptions the argument makes.
[Premise 1] Language tells us something about living conditions.
[Premise 2] PIE didn't have a word for "sea". PIE did have words for "winter", "snow", and "wolf".
[Conclusion] PIE people lived in a cold place isolated from the sea.
Do you see how useless Premise 1 actually is? Of course language tells us something about living conditions. You don't need to say that because it's obvious.
Instead, what I need to know, in order for Premise 1 to hook up with Premise 2, is specifically what it is that language tells me about living conditions. Specifically, I need to know that if a language had a word for something, then the feature that word points to existed in the living conditions of the people who spoke that language. (Had the word "winter" which points to a cold season, so PIE people lived in a place with cold seasons. Had the word "snow" which points to snow, so PIE people lived in a cold place. Had the word "wolf" which points to wolf and wolves are awesome.)
I also need to know that if a language lacked a word for something, then the feature that missing word points to did not exist in the living conditions of the people who spoke that language. (Missing the word "sea" which points to sea, so PIE people lived in a place with no sea.)
Those are the huge universal assumptions about the evidentiary power of language that the argument makes. (B) denies those assumptions. It denies universality. It makes the premises less supportive of the conclusion.
(B) doesn't claim whether PIE falls into its group. I know you want to say "we have to assume that PIE is one of those languages in (B)" but you don't. You don't because you don't have to prove the conclusion wrong (and you're trying to do that). Your job is only to make the existing premises less supportive of the conclusion.
That's a distinction introduced way back in the original Core Curriculum lessons on how to weaken arguments. Do not attack the conclusion. Attack the support the premises lend to the conclusion. In other words, wreck the assumptions.
To see how (B) weakens the argument, we need to first understand the assumptions the argument makes.
[Premise 1] Language tells us something about living conditions.
[Premise 2] PIE didn't have a word for "sea". PIE did have words for "winter", "snow", and "wolf".
[Conclusion] PIE people lived in a cold place isolated from the sea.
Do you see how useless Premise 1 actually is? Of course language tells us something about living conditions. You don't need to say that because it's obvious.
Instead, what I need to know, in order for Premise 1 to hook up with Premise 2, is specifically what it is that language tells me about living conditions. Specifically, I need to know that if a language had a word for something, then the feature that word points to existed in the living conditions of the people who spoke that language. (Had the word "winter" which points to a cold season, so PIE people lived in a place with cold seasons. Had the word "snow" which points to snow, so PIE people lived in a cold place. Had the word "wolf" which points to wolf and wolves are awesome.)
I also need to know that if a language lacked a word for something, then the feature that missing word points to did not exist in the living conditions of the people who spoke that language. (Missing the word "sea" which points to sea, so PIE people lived in a place with no sea.)
Those are the huge universal assumptions about the evidentiary power of language that the argument makes. (B) denies those assumptions. It denies universality. It makes the premises less supportive of the conclusion.
(B) doesn't claim whether PIE falls into its group. I know you want to say "we have to assume that PIE is one of those languages in (B)" but you don't. You don't because you don't have to prove the conclusion wrong (and you're trying to do that). Your job is only to make the existing premises less supportive of the conclusion.
That's a distinction introduced way back in the original Core Curriculum lessons on how to weaken arguments. Do not attack the conclusion. Attack the support the premises lend to the conclusion. In other words, wreck the assumptions.