Logical Reasoning

PT137 · S4 · Q14 Astronomer: Does a recent meteorite

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Astronomer: Does a recent meteorite from Mars contain fossilized bacteria?

Conclusion

Tagar's view cannot be right (it's wrong to say that the mysterious structures on this meteorite are not fossilized bacteria just because they're 0.1% the volume of Earth's smallest bacteria)

Evidence

According to Widerski and Tagar, Martian bacteria would shrink to 0.1% of their normal volume, if water or other nutrients were in short supply.

Evaluate

Since the author is trying to make these two positions seem mutually exclusive, I would probably be tempted to figure out how they could both simultaneously be true. How do we know that what W and T claim about Martian bacteria is even relevant to the stuff we're looking at on the meteorite? Is that stuff thought to be Martian bacteria? Is Martian bacteria's smallest size comparable to Earth bacteria's smallest size? Would the stuff on meteorite, if it were bacteria, have been in short supply of water or other nutrients?

Goal

I would honestly be confused about what we're looking for here and go to the answer choices for help. I know that our correct answer should help us fight the author's conclusion, so in this case it should help us argue that Tagar could be right.

14.

Which one of the following most accurately describes a flaw in the reasoning in the astronomer's argument?

  1. The argument presumes, without providing

    Too Strong

    The author doesn't need to assume that these three scientists have always held the views we're talking about. It wouldn't hurt the author's argument if 7 year old Tagar had a different view, for instance. It wouldn't even hurt the argument if any of these scientists had a different view at some earlier point in their professional career. Scientists are allowed (and encouraged) to update their views as new data and better theories emerge.

    2% picked this

  2. Correct

    The argument provides no justification

    Why this is right

    Does the author give preference to one set of authorities over another? Sure, she says "Tagar cannot be right, because he doesn't accept the views of Widerski and Martian", which implies that Tagar should accept the views of Widerski and Martian. But why should he? Does the author provide any justification for why we should think that Widerski and M are correct in their views, and Tagar must abide by their views? No. This is a rare but recurring pattern in which an argument presents a He Said / She Said type divide and then arbitrarily chooses one over the other without citing a reason for trusting once source over the other. If you want to see two more, look at the Flaw questions on Test 51. One is about studies regarding strenuous vs. nonstrenuous exercise. The other is about Typological vs. Mainstream classification of species.

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

    75% picked this

  3. The argument takes for granted

    Out of Scope: number of authorities

    This answer is tempting if we're asking ourselves, "hey, author, why are you favoring Widerski and Martian's views over Tagar's views?" We might speculate that it's because it's 2 vs. 1, but the author never says anything to the effect of, "Since more authorities think that bacteria can be that small in volume than think it can't be, it's more likely that bacteria could be 0.1% the volume of Earth's smallest bacteria." The argument wouldn't change at all if the author were rejecting Widerski and Martian and instead favoring Tagar. We would still be asking, "How did you pick one view over the other?" and the flaw would still be that the author didn't give us any reason why she picked one over the other.

    13% picked this

  4. The argument appeals to views

    Not a Flaw

    In this case, appealing to contradictory views was the whole point of the argument. It's not a flaw to say, "X must be wrong, because X's view contradicts with Y's view", as long as you add in the necessary premise of "And Y's view is correct."

    5% picked this

  5. The argument presumes, without providing

    Too Strong: all / equally Contradicted

    The author certainly doesn't need to assume that 100% of expert opinions have identical legitimacy. Not to mention, this assumption is contradicted by the fact that the author seems to think that Tagar's expert opinion is not well justified, whereas Widerski and Tagars expert opinion is.

    6% picked this

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