Support If a mechanical aerator is installed in a fish pool, the water in the pool can be properly aerated. ███ █████ ████████ ████ ████ ████ ███ ████ █ ██████████ ████████ ██ ████ ██ ████ ███ ████ ██ ███ ████████ ████████ ███████ ████████ ███████ ██████ ████ ██████ ███████ ██████████ ███ ████ ██ ████████ ████ ████ ████ ███ ███████
The stimulus presents a flawed conditional argument, concluding that fish in John's fish pool will not thrive. The argument explains that if a pool has a mechanical aerator, the water will be aerated. But John's pool doesn't have a mechanical aerator! The argument draws the sub-conclusion that John's pool must not be aerated—and aeration is necessary for fish to thrive, leading to the conclusion.
P1. mechanical aerator → aerated
P2. John's pool/mechanical aerator
P3 (SC). John's pool/aerated
P4. /aerated → /thriving fish
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C. John's pool/thriving fish
See the issue? The argument's sub-conclusion is improperly drawn, because it mixes up the sufficient and necessary conditions from the first premise. Mechanical aerators are sufficient to aerate a pool, but the argument treats them as necessary when drawing the sub-conclusion.
We can identify the structure that the correct answer will follow by abstracting our argument breakdown. We're looking for an answer that makes a conditional claim, then confuses the sufficient and necessary conditions to draw a flawed sub-conclusion. The answer should then apply a final conditional claim to reach the conclusion. Basically, it should look like this:
P1. A → B
P2. X/A
P3 (SC). X/B
P4. /B → /C
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C. X/C
However, diagramming each answer choice to find which one matches can be very time-consuming. One way we can save time is by doing a first pass to eliminate any clearly incorrect answer choices. If we see any answer choices that clearly follow a different flawed argument structure—or that aren't flawed at all—we can eliminate straight away and cut down the time we need to spend diagramming.
Which one of the following █████████ ████████ ██ █████ ██ █████████ ████ ██ ████ █████████ ██ ███ ████████ ██████
If alum is █████ ██ ██████ ██████ █████ ███ ███████ ███ █████ ██ ███ ████████ ██████████ █████ █████ ████ ███ ███ ████ ██ ███ ██████ ██████ ███ █████ ██ ███ ███████ ██████ ██ ████████ ██ ██████ ██████ █████ █████ ██ ████████ ████ ██████ ███████ ████ ███ ████ ██████ █████ █████████ ███████ ████ ███ ████ ██████
P1. add alum → brine replaces water
P2. Paula's brine/add alum
P3 (SC). Paula's brine/brine replaces water
P4. /brine replaces water → /crisp pickles
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C. Paula's brine/crisp pickles
This argument perfectly matches the stimulus in its flawed reasoning. (A) gives adding alum as a sufficient condition for brine to replace water, but then treats it as necessary. This leads to the flawed sub-conclusion that Paula's brine will not replace water, which then supports the conclusion that Paula will not have crisp pickles.
If pectin is █████ ██ ████ ███ ███ ████ ████ ███████ █ ███████ █████ ████ ██ ███████ ███ ████ ███ ████ ██ ██ █████ ██ ████ ███ ███ ████ █████ ██████ ███ █ ███████ █████ ████ ██ ██████ ██ ███ ████
P1. add pectin → jam gels
P2. /add pectin → /jam gels
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C. Harryjam gels → Harryadd pectin
(B) follows a different pattern of reasoning. It tells us that adding pectin is both necessary and sufficient for jam to gel. This lets us eliminate straight away—the stimulus doesn't have any conditions that are both necessary and sufficient.
If stored potatoes ███ ███ ███████ ██ █████████ ███ ████████ ████ ███ ███████ █████ ██ ███ ███████ █████████ ██████████ ██ ████ ██████ ███ ████████ ████████ ████ ██████ ███ ████████ ████ ███ ███████
P1. /ethylene exposure → /sprout
P2. beets/produce ethylene
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C. Sarastore potatoes with beets → /sprout
The quickest way to eliminate (C) is that it doesn't contain a sub-conclusion, which it would need to in order to match the stimulus. (C) has a simpler structure, with only 2 premises supporting its conclusion.
If a carrot █████ ██ ███████ ████ █████ ██ ███ █████ ███ ███████ ███ ██ ████ ██ ███ ██████ █████ ███████ ███████ █ █████ ██████ ███████ ██████ ██ ███ ██████ ███ ██████ █████ ███████ █████ █████ █████ ██████ ███ ██████ █████ ████ █████ ██ ███ █████ ███ ███████ ███ ██████ ██ ████ ██ ███ ███████
P1. fall mulch cover → safe until spring
P2. /fall mulch cover → /safe until spring
P3.Kevin's carrot patchfall mulch cover
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C. Kevin's carrot patchsafe until spring
Like (B), we can eliminate (D) straight away because it tells us covering carrots with mulch in the fall is both sufficient and necessary to protect them until spring. The stimulus has no conditions that are both sufficient and necessary; it's not a match.
If tomatoes are ███ ██████ ██ █ ████ ██████ █████ █████ █████████ ███████ ████████ █████ ███ ████ ████████ █████████ ██████████ █████ █████ ████ ███ █████ ███ ████████ ██ █ ████ ██████ ████ ██ █████████ ████████ █████ ██ █████████
P1. /dark storage -some→ seeds sprout
P2. seeds sprout -some→ /edible
P3.Maria's tomatoes/dark storage
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C. Maria's tomatoesmaybe inedible
One quick reason to eliminate (E) is that it relies on "some" statements, while the stimulus only uses absolute conditions. Similarly, the conclusion of (E) states a possibility, rather than being an absolute claim like the stimulus' conclusion.
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