Logical reasoning PrepTest 134 · Section 1 · Question 19

Incorrect. The argument is about what courts "should" do, not what they have the power to do. Even if the courts have absolute authority to exclude evidence, that doesn't mean they should exercise it in any given situation.

Incorrect. The argument establishes the criteria by which certain evidence is admitted to be widespread agreement in the scientific community, not absolute certainty. As such, the argument already considers that the scientific community might be accepting of evidence that isn't absolutely certain.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
not Widespread agreement in scientific community as to reliability → not Admitted in criminal trial
There is controversy in the scientific community as to the reliability of DNA tests
Therefore - Courts shouldn't allow DNA evidence in criminal cases

Answer Anticipation:
It can be hard to spot the flaw in this argument at first, so we'll have to rely on trends that we recognize on the test.

Here, we have a conditional statement that establishes something that's necessary for something to be admitted as evidence in a criminal trial—widespread agreement as to reliability of a test. It then applies that rule to DNA tests, and it reaches the conclusion that DNA tests shouldn't be allowed in criminal trials. Using the conditional statement, to reach that conclusion, it would need to be established that there isn't widespread agreement in the scientific community as to the reliability of DNA tests.

In general, when a flawed argument applies a conditional statement to a specific example, it's flawed in that it doesn't fully establish that sufficient condition. Here, it can appear at first look as if it does. However, there is a key shift—the conditional talks about there being a lack of widespread agreement as to reliability, and the fact about DNA testing is that there is "considerable controversy" about how reliable the tests are. While it's unlikely that you'd see where the gap is between those phrases, knowing the trend on the LSAT of having scenarios that don't actually meet the sufficient condition of the conditionals that are being applied to them, we should head into the answer choices looking for something explaining how there can be "considerable controversy" over the reliability of a test while still being widespread agreement that the tests are reliable.

Answer Explanation:
This answer threads the needle that we identified in the stimulus. If the scientific community all agrees that DNA tests are highly reliable (say, at least 99% accurate), but there's a controversy over whether they're just 99% accurate or, rather, 99.99% accurate (which would be 100 times more accurate), then the DNA tests shouldn't be excluded from criminal trials. This answer reflects a possibility the Analyst doesn't consider, so it's the correct answer.

Key Takeaway:
Two things. First, when an argument establishes a conditional and then applies it to a specific case, it's generally flawed in that it doesn't fully establish that the specific case meets the sufficient condition.

Second, when you're at a loss on a question, fall fully back on the patterns that we've identified during our studies. Knowing the above trend would allow you to have a solid guess as to what the flaw in the argument was, even if you couldn't see it specifically here. That makes it a lot easier to spot answer choice (C) as correct!

Incorrect. If anything, this aligns with the argument by establishing that agreement on reliability is a prerequisite for admission of evidence.

Incorrect. Noncriminal trials are out of scope of this argument about criminal ones.