Logical reasoning PrepTest 109 · Section 4 · Question 16

Incorrect. This answer connects the two terms in the conclusion, not the premises to the conclusion. Since the argument doesn't rely on the terms in the conclusion being connected to each other, this answer choice isn't necessary for the conclusion to hold.

Incorrect. This argument sets up truth as a necessary condition for something to be of scientific interest (Scientific interest → True). The contrapositive of that says not True → not Scientific interest. While that conditional lines up with the conclusion, the claim is true, so this answer doesn't apply to the claim made in the stimulus.

Incorrect. What matters is whether this popular claim is informative or of scientific interest, not what is generally the case. Even if popular slogans are generally informative and of scientific interest, this one could still not be.

Incorrect. If informative scientific claims can use terms in the way they are popularly used, this specific instance might not be one of those times. Since it doesn't necessarily apply here, it's not necessary for the argument to hold.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
A claim is true, but it's a tautology (repeats/proves itself)
Conclusion - The claim isn't informative, nor is it scientifically interesting

Answer Anticipation:
There's a lot of misdirection in this stimulus! It dives a lot into a discussion of evolutionary concepts in biology. However, if we start with the conclusion and work backwards, then we can much more easily focus on the relevant elements here.

The conclusion is that a given claim is neither informative nor of scientific interest. Why is that claimed to be the case? Because while it's true, it's a tautology.

If you know what tautology means, you can at this point anticipate an answer! If not, you can use the context from the previous statement to infer the definition. There, the argument says that the claim essentially repeats or proves itself. Since the premises discussing survival of the fittest do show that, there's no gap in that part of the argument.

So the jump is between a true but tautological statement and the judgments made in the conclusion. There's no premise or principle established about what makes a statement information or scientifically interesting, so the argument is assuming that a true-but-tautological statement is neither of those things. Let's find an answer establishing that.

Answer Explanation:
The argument establishes that a claim is true before concluding that it's not of scientific interest. As such, the argument is assuming that being true isn't sufficient for a claim to be of scientific interest. If truth were sufficient for such a judgment to be drawn, then this claim would be of scientific interest, completely undermining the conclusion, so this is the correct answer. (Note that it doesn't matter that this answer ignores whether the claim is informative. Since the argument concludes both that it's informative and scientifically interesting, anything necessary for either of those judgments is necessary for the argument to hold.)

Key Takeaway:
For Strengthen with Necessary Premise questions, always start with the conclusion and work backwards. You will generally be able to identify new concepts that aren't supported by premises, and from there you can work to find what concepts from the premises the author is assuming justifies the inclusion of those new concepts in the conclusion.