Logical ReasoningDifficulty: Hard

PT137 S4 Q6 Explanation

Columnist: Contrary to what many people

A free, expert breakdown of this official LSAT Logical Reasoning question.

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Stimulus

Columnist: Contrary to what many people believe, the number of species on Earth is probably not dwindling. Extinction is a natural process, and about as many species are likely to go extinct this year as went extinct in 1970. But the emergence of new species is also a natural process; there is the same rate as they have been for the last several centuries.

What this question is testing

Weaken

Your task

Find the choice that makes the argument's conclusion less likely to be true.

Common trap

Answers that look negative but attack a claim the argument never relied on.

Winning move

Find the assumption the argument depends on, then pick the choice that undermines it.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
6.

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

Answer choices

  1. Correct70% picked this

    In 1970 fewer new species emerged than

    Why this is right

    The author's argument is, "Why are these people saying the Earth is losing species? We're doing fiiiiine. We're doing just as good today as we were in 1970!" This answer choice: Hey, bro? In 1970, we were losing species. 1970 was a year with a "net loss" (we lost more than we gained). Our current year has the same rate of gain and same rate of loss as 1970, so this answer pretty much establishes that this year will also be a net loss. Thus, the number of species on Earth is dwindling, at least this year.

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

  2. Unclear Impact7% picked this

    The regions of the world where new species tend to emerge at the highest rate are also where species tend to go

    By focusing on a small part of Earth (this answer is only talking about outlier regions, the ones with the highest rate of speciation and the highest rate of extinctions), it's only going to give us part of the picture we need. For example, if an answer said, "The number of species that will go extinct in Canada this year is less than the number of new species that will be created", that wouldn't really help us assess the overall debate of the conclusion, which is about net gain/loss of species on the entire Earth. Even more importantly than "certain regions vs. entire Earth" is the fact that this answer doesn't even tell us within these regions whether it's a net gain or net loss of species. We're just told that in these regions they gain more species than anywhere and lose more species than anywhere, but we don't know whether they gain more than they lose or vice versa.

  3. Irrelevant13% picked this

    The vast majority of the species that have ever existed are

    We're told that species are always going extinct and being created. It's a pretty foregone conclusion that most species that have ever existed are now extinct. Earth has been creating (and extinguishing) forms of life for like 3 billion years. So the number of species currently alive vs. the number of species that have gone extinct over 3 billion years doesn't seem like a fair fight. The author is just arguing that our current rate of speciation eclipses our current rate of extinction (a net gain of species each year).

  4. Strengthens, if anything1% picked this

    There is no more concern now about extinction of species than there

    This makes it seem like nowadays doesn't seem any worse to people than 1970 did, which would help the author argue, "Relax ... we're not falling off a cliff. Look we're no worse off than 1970." Had we said, "yes, author, we're losing species at the same rate as 1970, but there is much more concern now than there was in 1970 about losing species", that would have helped us weaken a little, but given that it's opinion not fact, it doesn't really have much impact.

  5. Irrelevant9% picked this

    Scientists are now better able to identify species facing serious risk of extinction than they

    Having a better ability to identify species on the brink of extinction might be relevant to how likely we are to save the species going extinct, but it doesn't do anything to help us judge the math of how many species went extinct this year vs. how many new species emerged this year.

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