Logical Reasoning

PT118 · S4 · Q11 Between 1976 and 1985, chemical

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Between 1976 and 1985, chemical wastes were dumped into Cod Bay.

Conclusion

The fin deformity in Cod Bay's bluefin cod must have been caused by the chemicals dumped there.

Evidence (since)

Chemical wastes were dumped into the bay between 1976 and 1985, and today 3 percent of the bay's bluefin cod have deformed fins.

The chemicals are known to cause genetic mutations.

Evaluate

The number 1 pattern on Strengthen / Weaken / Evaluate is Explain Curious Fact, and here we go again.

The conclusion is Causal and even embeds in it the Curious Fact we're trying to explain.

CURIOUS FACT: why do 3% of bluefin cod have deformed fins?

AUTHOR'S CAUSAL EXPLANATION: the chemicals dumped into Cod Bay led to genetic mutations which resulted in deformed fins.

We treat Evaluate questions essentially as Weaken questions, so the two ways to weaken an argument like this are 1. Suggest an Alternate Explanation for the curious fact 2. Hurt the Plausibility of the Author's Explanation.

Goal

Let's get rid of the four answers with the power to weaken. They would either be asking a question that leads to some different reason why the cod have deformed fins, or they'd be asking a question that could lead us to question how plausible this story is that .

11.

The answer to each of the following questions would be helpful in evaluating the representatives' claim EXCEPT:

  1. What is the incidence of

    Opposite

    If 3% of bluefin cod that aren't exposed to chemicals have deformed fins, then a 3% rate of deformed fins has nothing to do with chemicals. It might just be the normal base rate of deformed fins in any population of bluefin cod. This has the power to weaken by producing Effect w/o Cause data points (these cod have the deformed fins even though they weren't exposed to the chemical wastes), which undermine the plausibility of the author's explanation.

    6% picked this

  2. What was the incidence of

    Opposite

    Just like (A), if rate of deformed fins was 3% because chemical dumping even began, then a 3% rate of deformed fins has nothing to do with chemicals. It might just be the normal base rate of deformed fins in any population of bluefin cod. This has the power to weaken by producing Effect w/o Cause data points (these pre-dumping cod have the deformed fins even though they weren't exposed to the chemical wastes).

    3% picked this

  3. Correct

    Has the consumption of the

    Why this is right

    Whether eating the deformed fish harms people has no bearing on what caused the deformity. The fins could be deformed by the chemicals and still be harmless to eat, or deformed by something else and still be dangerous. The representatives' claim is about the origin of the deformity, and this question is about a downstream consequence. Its answer leaves the causal claim untouched either way.

    Skill tested: Evaluate · how this choice captures the argument's function is the move to repeat next time.

    85% picked this

  4. Are bluefin cod prone to

    Opposite

    If we say, "Yes, these cod are prone to a natural disease that can cause fin deformities", then we have a way to weaken. We can suggest an Alternate Explanation for the curious fact. The fin deformities aren't from chemical waste that induced genetic mutations. They're from a naturally occurring disease.

    4% picked this

  5. Are there gene-altering pollutants present

    Opposite

    If we say, "Yes, there are other gene-altering pollutants in Cod Bay", then we have a way to weaken. We can suggest an Alternate Explanation for the curious fact: the fin deformities aren't from chemical wastes. They're from other gene-altering pollutants in the water!

    4% picked this

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