Halley's Comet

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Halley's Comet

by zazoz » Mon May 13, 2013 9:24 am
Anne: Halley's Comet now in part of its orbit relatively far from the Sun, recently flared brightly enough to be seen by telescope. No comet has ever been observed to flare so far from the sun before, so such a flare must be highly unusual.

Sue: Nonsense. Usually no one bothers to try to observe comets when they are so far from the Sun. This flare was observed only because an observatory was tracking Halley's Comet very carefully.

Sue challenges Anne's reasoning by

(A) pointing out that Anne's use of the term "observed" is excessively vague.
(B) drawing attention to an inconsistency between two of Anne's claims.
(C) presenting evidence that directly contradicts Anne's evidence.
(D) offering an alternative explanation for the evidence Anne cites.
(D) undermining some of Anne's evidence while agreeing with her conclusion.


[spoiler]
OA: D[/spoiler]




I am completely satisfied with the reason(s) why 'D' must be the correct answer, but I cant figure out why the 'B' cannot be the right answer. I see somehow inconsistency in Anne's claims, so I wonder what is the problem. Maybe I misunderstood the meaning of "inconsistency". I will be very glad if experts and seniors offer me some explanations for my doubt.

Regards.
Source: — Critical Reasoning |

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by hemant_rajput » Tue May 14, 2013 11:05 pm
IMO what B is pointing is the inconsistency between the 2 of Anne's claims - "No comet has ever been observed to flare so far from the sun before" and "flare must be highly unusual".

At first I also fall for the B, but then I realize she is not point out the inconsistency but the flaw in Anne's reasoning; This flaw is what D is pointing out: An alternative explanation.

hope this helps
I'm no expert, just trying to work on my skills. If I've made any mistakes please bear with me.

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by shenoydevika » Tue May 14, 2013 11:53 pm
Option B is incorrect because there is NO inconsistency in Anne's statements. She says that no comet has ever been observed to flare so far from the sun before (which is true)and so this event must be highly unusual.(which is her conclusion) The statements she makes do not contradict each other at all. In fact, her conclusion seems logical were it not for the explanation provided by Sue.

Sue just provides an alternative explanation to undermine Anne's conclusion. The comet flaring may not be an unusal event as other comets haven't been similarly oberved to see whether they flare.

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by zazoz » Thu May 16, 2013 12:36 am
shenoydevika wrote:Option B is incorrect because there is NO inconsistency in Anne's statements. She says that no comet has ever been observed to flare so far from the sun before (which is true)and so this event must be highly unusual.(which is her conclusion) The statements she makes do not contradict each other at all. In fact, her conclusion seems logical were it not for the explanation provided by Sue.

Sue just provides an alternative explanation to undermine Anne's conclusion. The comet flaring may not be an unusual event as other comets haven't been similarly observed to see whether they flare.
Thank you, As I guessed before I misinterpret the "Inconsistency". Would you explain me what would consider inconsistency?