Logical Reasoning

PT109 · S4 · Q16 The familiar slogan “survival of

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

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

The familiar slogan “survival of the fittest” is popularly used to express the claim, often mistakenly attributed to evolutionary biologists, that the fittest are most likely to survive.

Conclusion (so)

The claim that is neither informative nor of scientific interest.

Intermediate Conclusion

The claim is a tautology (i.e. like "A is A.").

Evidence

People use the slogan "survival of the fittest" to express the idea that "the fittest are most likely to survive".

However, biologists use the term "fittest" to mean "most likely to survive".

Evaluate

A tautology is a fancy word that means "a self-justifying truth". For example, the sentence "I am speaking English right now" is guaranteed to be true, without recourse to any premises. Similarly, "good things are better than bad things".

The author is saying that "survival of the fittest" is meant to express that "the fittest are most likely to survive". What do we mean by fittest?

Well, you might be thinking, .

But biologists use this term as a synonym for .

The author is thus explaining that if we use that definition of 'fittest', then saying that "the fittest are more likely to survive" is as silly and empty as saying .

However, we may ask, when people use the phrase "survival of the fittest", is that what they mean by fittest? Do they mean "most likely to survive" or do they mean "the strongest / biggest / smartest / fastest" type stuff.

Goal

The author is assuming that when people use the familiar slogan "survival of the fittest" to express the idea that the fittest are most likely to survive, they are intending to employ the biologists' usage of that word.

(The author is also assuming that "if something is a tautology, then it is neither informative nor of scientific interest)

16.

The argument above depends on assuming which one of the following?

  1. All claims that are of

    Too Strong: all

    Since this is conditional, we can ask ourselves whether the author ever made this reasoning move: if X is of scientific interest ? X is informative No, she didn't. Both of those terms appear for the first time in the conclusion. She isn't moving from one of those ideas in the Premise to the other idea in the Conclusion. Another way to say it's wrong: if we negated this and said, "Yo, author -- there is at least one claim that is of scientific interest that is not informative", it wouldn't weaken her argument in the slightest, since her argument is about a claim that supposedly is neither of scientific interest nor informative.

    3% picked this

  2. Only claims that are true

    Too Strong: only Bad Trigger Match

    Since this is conditional, we can ask ourselves whether the author ever made this reasoning move: if X is not true ? X is not of scientific interest No, she didn't. She does try to conclude that something is not of scientific interest, so the right side is fine, but she didn't say that "this claim is not true". In fact, she said the opposite. This claim is clearly true. Would it hurt the author's argument if there was a false claim that was of scientific interest? Nope.

    1% picked this

  3. Popular slogans are seldom informative

    Too Strong: seldom

    This argument is only about one popular slogan. Our author thinks that this slogan isn't informative or of scientific interest, but there's no reason she has to assume that most popular slogans are that way, which is what this answer choice says.

    13% picked this

  4. Informative scientific claims cannot use

    Too Strong: cannot

    This is very strong language. Informative scientific claims never use terms the way they are popularly used? The author is only trying to prove that this claim, which is popularly used, is not informative. She doesn't need to assume any permanent connection between being scientifically informative and being popularly used. If we negated this and said that, "informative scientific claims can use terms the way they are popularly used", that wouldn't hurt this argument at all.

    10% picked this

  5. Correct

    The truth of a purported

    Why this is right

    We would guess this answer purely from strength of language, if we had to take a 10 second guess by looking at the answers. Saying that "X is not sufficient for Y" is merely saying "It's possible that X is true and Y is not true". Did this author think it's possible that - a purported scientific claim is true and - the claim is not of scientific interest ? Definitely! Her final sentence says this claim is true and is not of scientific interest. If we negated this, would it weaken: "The truth of a claim is sufficient for it to be of scientific interest"? Definitely! This negation would end up contradicting part of the author's conclusion. She concedes that this claim is true, so according to the negation, that would prove that the claim is of scientific interest. And yet she's trying to conclude the opposite of that. Overall, this is a weird question. The answer ends up feeling more like a thought you can derive / infer from the author claims, rather than a claim that fills in a reasoning gap. But like every single Necessary Assumption question, if we went by the standard of "Which answer, when negated, most weakens", we could still get this right.

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

    72% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free