According to some astronomers, Earth

Answer choices

1. A

   Not a Flaw13% picked this

   makes a bold prescription on the basis of evidence that establishes only a high probability

   There's nothing really unreasonable about making a bold prescription based on a high probability for a disastrous event. If there's a 70% chance of disaster, it's time to make some bold moves! The author's evidence did not establish a high probability of a disastrous event. We do not accept that we can expect Earth to be struck in the near future, because we're talking about an average occurrence of once every 100 million years, so the margin of error is over a million years!

   13%
2. B

   Opposite11% picked this

   presumes, without providing justification, that the probability of a chance event’s occurring is not affected by whether the event has occurred during a period

   This saying that the author avoided committing the famous Gambler's Fallacy -- instead of thinking "since none of the last five rolls were a 3, the next roll of the die will probably be a 3", this answer says our author was thinking, "Hogwash! The previous events don't influence the probability of what's coming." Our author is thinking that "the fact that we haven't had any big ol' meteorites in the last, nearly 100 million years indicates that we can expect such a meteorite in the near future".

   11%
3. C

   Correct68% picked this

   moves from evidence about the average frequency of an event to a specific prediction about when the next

   Why this is right

   This is just making the complaint that the author is treating average too literally. If I know that there's a Presidential scandal, on average, once every 18 months, I can't use that to make specific predictions about when the next scandal will be. It's just an average. Sometimes the gaps between will be shorter than 18 months, sometimes longer. Similarly, sometimes it might be 80 million years between strikes, sometimes 120 million years between.

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

   68%
4. D

   Not an Objection3% picked this

   fails to specify the likelihood that, if such a meteorite should strike Earth, the meteorite would indeed

   Since the pronoun in "such meteorite strikes" and "such a meteorite" refers back to "a meteorite large enough to cause an ice age", it's already baked into the concept of what we're talking about that the meteorite would cause an Ice Age. That's not our problem with the reasoning.

   3%
5. E

   Contradicted4% picked this

   presumes, without providing justification, that some feasible means can be found to deter

   The author's conclusion is just saying, "let's spend some money to determine whether there is or isn't some feasible means". She's not assuming the answer will be YES, just assuming it's worth trying. We could fix this by saying, "presumes that the chance of there being a feasible means is high enough that it warrants funding".

   4%