Logical Reasoning

PT103 · S2 · Q12 The higher the average fat intake

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The higher the average fat intake among the residents of a country, the higher the incidence of cancer in that country; the lower the average fat intake, the lower the incidence of cancer.

Conclusion

People who want to reduce their risk of cancer should reduce their fat intake.

Evidence

The higher the average fat intake of a country, the higher the incidence of cancer (the lower the intake, the lower the risk).

Evaluate

Since the author is looking at a Curious Comparison in the evidence and then making a causal assumption to get to his conclusion, we can use our Curious Fact / Explanation mindset.

Curious Fact ... why is there a correlation between fat intake and cancer risk? Author's Explanation .... the fat intake is causing the increased cancer risk.

Any time we formulate a sentence as "if you want X, you should do Y", we're implying a causal relationship that doing Y leads to X.

The two pressure points for a causal argument are - Alternate Explanations for the curious fact - the plausibility of the Author's Explanation

Why else could it be that fat intake and cancer risk are correlated? With correlations, we always want to consider Reverse Causality (maybe the cancer comes first, and then people end up eating a lot of fat as a result of the cancer diagnosis) or Third Factor (maybe the cancer and the fat are both symptoms of some underlying cause, like cigarette smoking. Perhaps smoking cigarettes leads to higher rates of cancer but also causes food cravings for fatty foods).

Goal

Since this is Weaken, we would primarily look for an answer that provides an Alternate Explanation for why fat and cancer are correlated, but secondarily look for answers that try to undermine the plausibility that fat intake could cause elevated cancer risk.

12.

Which one of the following, if true, most weakens the argument?

The differences in average fat
Unclear Impact
If differences in fat are just symptoms of different traditional diets, maybe there's some other ingredient in some of those traditional diets that is really the thing causing the cancer. This almost has the makings of an alternate explanation, except a couple things make it way too weak and vague: - "varying makeup" of diet doesn't give us any specific ingredient in the higher-fat traditional diets that we could now suggest is the real cause of cancer. We would just be totally speculating that within these varying diets there is a carcinogenic ingredient that isn't fat but is only / mostly present in high-fat diets. - this answer is creating a weak connection, since it's only saying that differences are often due to traditional diet. The correlation in the evidence we're trying to explain is much stronger than that, because it's saying "in all cases, the higher the fat, the higher the rate of cancer".
2% picked this
The countries with a high
Not a Common Sense Connection
This answer is phrased more strongly than (A), since "tend to" is more than 50% whereas "often" does not have to be more than 50%. Since high fat is linked to wealth, we could potentially say that wealth, not high fat, is the real cause of the elevated cancer rate. But that strains common sense. If we asked 10 people on the street, "does being wealthy increase your risk of cancer", it doesn't seem like we'd get more than 5 saying "of course".
1% picked this
Cancer is a prominent cause
No Impact Relative vs. Absolute
This answer is attractive to people because it seems to pair up Low-Fat with High-Cancer. But it's not conflicting with the correlation we were given. Cancer is a prominent cause of death in every country. (it's probably the #2 cause of death behind heart disease) "a prominent cause" just means "significant / important". It doesn't mean #1 cause of death. So the author wouldn't blush to hear that in countries with low fat intake, cancer is a significant cause of death. The author was never thinking that countries with low fat intake didn't have lots of cancer. He just said they had less cancer than countries with high fat intake.
39% picked this
Correct
The countries with high average
Why this is right
This provides a strong (seemingly perfect) correlation between higher fat and higher environmental pollution. So we could potentially say that it's not the high fat causing cancer, it's the environmental pollution. Is that a common sense causal link? If we asked 10 random people, "Does environmental pollution increase your risk of cancer?", we would probably get a bunch of people saying, "Yes". So this answer provides a Third Factor alternate explanation. The reason fat and cancer are correlated is because environmental pollution is correlated with fat and causes cancer.
Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.
54% picked this
An individual resident of a
No Impact
This doesn't look like a tempting answer for Strengthen / Weaken / Paradox, since it's so weakly worded. By using the expression "something may be true", it's just saying it's possible something happens at least once. The correlation we're given is averaging together the whole population, not saying they're identical in terms of fat intake and cancer risk. So it doesn't offend the author to hear that some data points don't conform to the average.
5% picked this

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