Critical Reasoning

Although the geological record contains some hints of major meteor impacts preceding mass extinctions, there were many extinctions that did not follow any known major meteor impacts. Likewise, there are many
records of major meteor impacts that do not seem to have been followed by mass extinctions. Thus the geological record suggests that there is no consistent causal link between major meteor impacts and mass
extinctions.

Which one of the following assumptions enables the argument’s conclusion to be properly inferred?

(A) If there were a consistent causal link between major meteor impacts and mass extinctions, then all major meteor impacts would be
followed by mass extinctions.

[spoiler]OA:A[/spoiler]
(B) Major meteor impacts and mass extinctions cannot be consistently causally linked unless many mass extinctions have followed major
meteor impacts.

(C) Of the mass extinctions that did not follow any known major meteor impacts, few if any followed major meteor impacts of which the
geological record contains no hints.

(D) If there is no consistent causal link between major meteor impacts and mass extinctions, then not all mass extinctions could have
followed major meteor impacts.

(E) There could be a consistent causal link between major meteor impacts and mass extinctions even if not every major meteor impact has
been followed by a mass extinction.


OA to follow soon!!

IMO C). I don't know how to explain this though.

phew......what a question.
I am really confused between A,B and D. they seem almost the same to me

I think i'll go with B. not sure why though

Expert please help. would really appreciate your comments on this one.

vinaynp wrote:IMO C). I don't know how to explain this though.

I was thinking in terms of correlation does not imply causation theory. I was assuming that there is no causal relation at all.

I missed on there is no consistent causal link .

Recognize when an argument deals with correlation
vs. causation—that issue will inevitably be at the
heart of the question.

The author rejects any consistent causal link between
meteor impacts and mass extinctions, on the ground
that there are many instances of one of them
happening without the other—notwithstanding the fact
that sometimes the former is followed by the latter.
Those occasional exceptions are no impediment to the
conclusion when (A) is proven. Note (A)’s
contrapositive, which pushes the conclusion closer to
validity: because not all impacts are followed by
extinctions, there is no consistent causal link.
(B) offers a necessary condition for the existence of a
causal link, but it’s one that might apply in this case.
That is, if the “unless” clause is talking about the
impacts and extinctions mentioned in the stimulus’s
first sentence—and it could be—then the causal link is
strengthened rather than denied.
(C) hinges on whether the record does or does not
have hints of meteor impacts, but this issue is not
central to an argument about the effect (or lack
thereof) of the impacts that are confirmed.
(D) Construct (D)’s contrapositive: Because some
mass extinctions did follow major meteor impacts, then
there is a consistent causal link. Then, you’ll readily
see why this choice weakens rather than strengthens
the conclusion.
(E) By allowing the possibility of a consistent causal
link despite the many exceptions that the author has
cited, (E) serves to weaken the logic severely.


Hope this helps!!!

Cheers
TJ

turbo jet wrote:Recognize when an argument deals with correlation
vs. causation—that issue will inevitably be at the
heart of the question.

The author rejects any consistent causal link between
meteor impacts and mass extinctions, on the ground
that there are many instances of one of them
happening without the other—notwithstanding the fact
that sometimes the former is followed by the latter.
Those occasional exceptions are no impediment to the
conclusion when (A) is proven. Note (A)’s
contrapositive, which pushes the conclusion closer to
validity: because not all impacts are followed by
extinctions, there is no consistent causal link.
(B) offers a necessary condition for the existence of a
causal link, but it’s one that might apply in this case.
That is, if the “unless” clause is talking about the
impacts and extinctions mentioned in the stimulus’s
first sentence—and it could be—then the causal link is
strengthened rather than denied.
(C) hinges on whether the record does or does not
have hints of meteor impacts, but this issue is not
central to an argument about the effect (or lack
thereof) of the impacts that are confirmed.
(D) Construct (D)’s contrapositive: Because some
mass extinctions did follow major meteor impacts, then
there is a consistent causal link. Then, you’ll readily
see why this choice weakens rather than strengthens
the conclusion.
(E) By allowing the possibility of a consistent causal
link despite the many exceptions that the author has
cited, (E) serves to weaken the logic severely.


Hope this helps!!!

Cheers
TJ

Awesome Questions and explanation.......Keep posting.

Hey TJ. Can you give another example where the contrapositive technique can be used to decide whether an assumption holds true? I was stuck between (A) and (B) but chose (B) because a negation of (B) would destroy the conclusion.

Looking at it now, A makes sense