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Kale has more nutritional value than spinach. But since collard greens have more nutritional value than lettuce, it follows that kale has more nutritional value than lettuce.
Any of the following, if introduced into the argument as an additional premise, makes the argument above logically correct EXCEPT:
| Text from Passage | Analysis |
| Kale has more nutritional value than spinach. |
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| But since collard greens have more nutritional value than lettuce, it follows that kale has more nutritional value than lettuce. |
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"The argument gives us two separate comparisons (kale vs spinach, and collard greens vs lettuce) and then tries to conclude something about kale vs lettuce. But there's a huge logical gap - we have no connection between these comparisons that would let us make that jump."
"Kale has more nutritional value than lettuce"
"The argument is missing a crucial link. We know kale > spinach and collard greens > lettuce, but to conclude kale > lettuce, we'd need to know how these vegetables relate to each other (like spinach > collard greens, or kale > collard greens, etc.). Right now, the conclusion doesn't follow from the premises."
Strengthen EXCEPT - We need to find premises that would NOT make the argument logically correct, while the other four options would fix the logical gap
The argument makes comparative nutritional value claims between specific vegetables (kale vs spinach, collard greens vs lettuce, kale vs lettuce)
Since this is an EXCEPT question for strengthen, we skip the typical prethinking process. The question asks us to identify which option would NOT make the argument logically valid. The argument currently has a logical gap - it jumps from 'kale > spinach' and 'collard greens > lettuce' to conclude 'kale > lettuce' without establishing any connection between these comparisons. Four answer choices will bridge this gap and make the argument valid, while one will not.
If we add this premise, we get the chain: \(\mathrm{Collard\ greens} > \mathrm{Kale} > \mathrm{Spinach}\), and separately \(\mathrm{Collard\ greens} > \mathrm{Lettuce}\). But this creates a critical problem - we still have no way to connect kale and lettuce! We know both vegetables are less nutritious than collard greens, but that doesn't tell us anything about their relationship to each other. Kale could be more nutritious than lettuce, less nutritious than lettuce, or equal to lettuce. This premise does NOT make the argument logically valid.
This creates a perfect chain: \(\mathrm{Kale} > \mathrm{Spinach} > \mathrm{Lettuce}\). Since kale beats spinach, and spinach beats lettuce, we can definitively conclude that kale beats lettuce. This premise makes the argument logically correct.
This gives us: \(\mathrm{Kale} > \mathrm{Spinach} > \mathrm{Collard\ greens} > \mathrm{Lettuce}\). Again, we have a clear chain from kale all the way down to lettuce, so we can validly conclude \(\mathrm{kale} > \mathrm{lettuce}\). This premise makes the argument logically correct.
This creates: \(\mathrm{Kale} > \mathrm{Spinach} = \mathrm{Collard\ greens} > \mathrm{Lettuce}\). Since kale beats spinach, and spinach equals collard greens, and collard greens beat lettuce, we can conclude kale beats lettuce. This premise makes the argument logically correct.
This gives us: \(\mathrm{Kale} = \mathrm{Collard\ greens} > \mathrm{Lettuce}\). Since kale equals collard greens in nutritional value, and we know collard greens beat lettuce, kale must also beat lettuce. This premise makes the argument logically correct.