Logical Reasoning

PT138 · S3 · Q20 Scientist: Given the human tendency

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Scientist: Given the human tendency to explore and colonize new areas, some people believe that the galaxy will eventually be colonized by trillions of humans.

Conclusion

The odds are slim that colonization of the galaxy by trillions of humans will ever happen.

Evidence

If trillions of humans were to colonize the galaxy, then the vast majority of humans who ever lived would be alive during that phase.

Since we have no reason to think that we are unrepresentative humans, the odds would therefore be overwhelming that we would be alive during the period of galactic colonization.

But we're not alive during that period (there are not currently trillions of humans colonizing the galaxy).

Evaluate

This is a real crappy argument, but our job on Method isn't to evaluate the argument.

In real life, smart tech people like Elon Musk make arguments similar to this to argue that we probably live in a simulation: if there were simulated universes, there would be way more simulated universes than real universes, so the probability would be much higher that you live in a simulated universe than in the real universe. Thus, you probably live in a simulated universe.

On Method, our job is just to characterize the type of evidence used or the type of move the author made, and the correct answer usually sounds like one of these options: analogy, rule out alternatives, implications of logic, example / counterexample, definition / distinction, overlooked consideration, dubious assumption, alternative explanation

The key moment that would stick out to me in this argument is the moment of "Suppose they're right ...." / "If that were really so ... "

This is what we mean when we say "implications of logic". The second half of an If/Then statement is called its outcome, its consequence, its necessary implication.

So authors will either say, .

Or, like we're doing in this argument, authors will say,

This 2nd style is arguing via contrapositive logic. If you were right → implication X But implication X is not the case. Thus, you are not right.

Goal

We will probably see an answer saying the author discussed the implications of a certain belief, and then established that an implication is not true, thus that the belief is not true. (on in this case, "the odds are slim" that the belief is true)

20.

The scientist's argument proceeds by

  1. reasoning that because an event

    Weak Premise Match

    The conclusion is definitely saying that an event (human colonization of the galaxy) has a low probability of occurring. But the premise isn't just saying "human colonization hasn't happened yet". It's a much more complicated argument based on probabilities and representative sampling and such. I will say, the fact that the author says "we are not alive during this period" is an indication that "an event (galactic colonization) has not occurred". But this answer makes it sound too much like the author's logic was simply, "If ain't happened yet, then it probably won't happen".

    26% picked this

  2. drawing a conclusion that implicitly

    No Contradiction

    There's almost never contradictions in LSAT paragraphs (i.e. "inconsistent / incompatible claims"). The conclusion drawn is that "it's unlikely that galactic colonization will ever happen", so according to this answer, one of the premises that the argument accepts is that "it's likely that galactic colonization will happen". There, of course, is no premise that sounds like that. When the author goes into hypothetical mode of, "Suppose it did happen", that does not count as the argument accepting that it's likely there will one day be galactic colonization.

    11% picked this

  3. taking for granted that dependable

    Too Strong: cannot ever be

    It's weird to see a Necessary Assumption answer choice showing up here ("takes for granted / presumes / fails to establish" = Necessary Assumption). Was our author assuming that present facts cannot ever allow us to make dependable predictions? Heavens no. She hasn't committed herself to that crazy-extreme claim.

    4% picked this

  4. Correct

    inferring that since an event

    Why this is right

    Any time an answer is structured infers that since X, Y we would see the X part as referring to the evidence and the Y part as referring to the conclusion. Is the conclusion saying "a hypothesis is probably false"? It's saying that "the belief that the galaxy will eventually be colonized by trillions of humans" is probably false. It's a little weird to call that a hypothesis, which is normally used to mean "a claim that posits an explanation for a phenomenon". This is more using "hypothesis" to mean "speculative guess", which is normal in real life but very uncommon in LSAT. What makes it more like a hypothesis than just a mere prediction, I suppose, is that the first sentence is saying, "Given that humans tend to explore and colonize new areas, people hypothesize that will one day colonize and inhabit the galaxy". Okay, we've begrudgingly signed off on the conclusion part. Was the evidence saying that "an event is taken to be likely on a given hypothesis"? Yes, that's saying "given the truth of this hypothesis, event X would be likely", and our evidence was saying, "were the hypothesis that humans colonized the galaxy true, it is likely (the odds are overwhelming) that we would be living during this time period". Can we call that an event? Yeesh, I'd rather not. This correct answer is miserable. Can we say that event has not occurred? Yes, the author says "we are not alive during this period", so the 'event' of us living during the time of galactic colonization has not occurred. If we were to put this answer in more apt terms, it's saying that the author is "concluding that, since a likely implication of a given prediction is not the case, the prediction will probably not occur." This is definitely a great example of the ol' mantra: We have to pick the best-available answer, even if it's not quite an acceptable answer. I think hypothesis and event are both really curiously bad terms for this conversation.

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

    54% picked this

  5. making a prediction far into

    Not the Author

    This is what "some people" are doing in the first sentence. This question wants to know what method of reasoning is being used by the Scientist who wrote this whole paragraph.

    5% picked this

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