BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Theory

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 882
Joined: Fri Feb 20, 2009 2:57 pm
Thanked: 15 times
Followed by:1 members
GMAT Score:690

Theory

by crackgmat007 » Tue Aug 04, 2009 10:32 am
A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account, Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.
The argument above is open to the objection that it makes the questionable assumption that
A. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory false
B. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the
Ptolemaic theory
C. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidence
D. numerous counterexamples were necessary in order to show the Ptolemaic theory To be false
E. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Pls provide reasoning for your answer. OA to follow.
Top
Source: — Critical Reasoning |
Master | Next Rank: 500 Posts
Posts: 186
Joined: Sat Sep 02, 2006 7:50 pm
Thanked: 10 times
Followed by:1 members

by ogbeni » Tue Aug 04, 2009 10:55 am
E.

1st Premise: A theory is either true or false
2nd Premise: Galileo's observations proved the Ptolemiac theory false
3rd Premise: since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account
4th and Unstated Premise: The Ptolemaic and Copernican theories, being inconsistent, cannot both be false
Conclusion: Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory

If you Negate the Unstated premise - The ptolemiac and Copernican theories, being inconsistent can be false - concluding that Galileo's observations prove the truth of Copernican theory can not stand.

There is no other basis for ascribing truth to Copernican theory other than stating that 'since both cannot be false' and Copernican theory is inconsistent with Ptolemiac, therefore Copernican = True
Top
Master | Next Rank: 500 Posts
Posts: 435
Joined: Sat May 02, 2009 3:55 am
Thanked: 17 times

by madhur_ahuja » Tue Aug 04, 2009 10:55 am
IMO C.

Its like A proved false B. and C proved false B. So A proved C correct.

But I am confused if the question is asking assumption or objection ?
IMO C is the objection and not assumption.

Assumption would have been:
the Ptolemaic and Copernican theories, being inconsistent, are based on exactly the same evidence
Top
Master | Next Rank: 500 Posts
Posts: 435
Joined: Sat May 02, 2009 3:55 am
Thanked: 17 times

by madhur_ahuja » Tue Aug 04, 2009 10:57 am
IMO C.

Its like A proved false B. and C proved false B. So A proved C correct.

But I am confused if the question is asking assumption or objection ?
IMO C is the objection and not assumption.

Assumption would have been:
the Ptolemaic and Copernican theories, being inconsistent, are based on exactly the same evidence
Top
Master | Next Rank: 500 Posts
Posts: 186
Joined: Sat Sep 02, 2006 7:50 pm
Thanked: 10 times
Followed by:1 members

by ogbeni » Tue Aug 04, 2009 11:06 am
@madhur

The stem asks to identify the questionable foundation of the conclusion - my paraphrase BTW

Conclusion = Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account, Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory

We are not meant to provide correction for the argument made. We're just supposed to identify the basis for the weak argument made
Top
Master | Next Rank: 500 Posts
Posts: 197
Joined: Sun May 18, 2008 2:47 am
Thanked: 12 times

Re: Theory

by shahdevine » Tue Aug 04, 2009 1:27 pm
crackgmat007 wrote:A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account, Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.
The argument above is open to the objection that it makes the questionable assumption that
A. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory false
B. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the
Ptolemaic theory
C. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidence
D. numerous counterexamples were necessary in order to show the Ptolemaic theory To be false
E. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Pls provide reasoning for your answer. OA to follow.

i am going to go on the limb here with b. and it starts with the first statement. which says a theory is either true or false. this is a false dichotomy. and how it relates is that just because Galileos observation is consistent with Copernicus does not necessarily make the theory true. We are assuming that Galileo's observation is the right one, but what makes Galileo credible enough to warrant that truth value.

hmmm...on further thought. E could be it and for the same reason. Why does a theory have to be mutually exclusive ->true/false? why can't it be true/true or based on the answer choices false/false?

please provide oa.
Last edited by shahdevine on Tue Aug 04, 2009 10:23 pm, edited 1 time in total.
Top
Legendary Member
Posts: 1161
Joined: Mon May 12, 2008 2:52 am
Location: Sydney
Thanked: 23 times
Followed by:1 members

by mehravikas » Tue Aug 04, 2009 1:32 pm
IMO - C

X is true
Y - when introduced was inconsistent with X, therefore Y is false
X - is not proven to be false
Therefore, can we say that Y is now true, just because X has been proven false.

do they rely on the same evidence or findings?
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 393
Joined: Sun Jul 19, 2009 9:18 pm
Location: Chicago
Thanked: 8 times

Re: Theory

by riteshbindal » Tue Aug 04, 2009 9:10 pm
crackgmat007 wrote:A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account, Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.
The argument above is open to the objection that it makes the questionable assumption that
A. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory false
B. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the
Ptolemaic theory
C. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidence
D. numerous counterexamples were necessary in order to show the Ptolemaic theory To be false
E. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Pls provide reasoning for your answer. OA to follow.
IMO E: It says that A (Ptolemaic theory) is false and A is inconsistent with B(Copernican theory). Therefore, B is true.
So definitely the questionable assumption is that A and B, being incosistent, cannot both be false. This implies that if A is true, B is false and if B is true A is false. So this suggests E to be the questionable assumption used by the author.

I have seen that many of our peers are considering C to be correct answer. Let's analyze C as well.
C. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidence
Ok. This statement says that A and B, being inconsistent, can not be based on same evidence. However, we are not discussing any evidence support for this CR. Also, even if we assume that both are based on different evidences, those evidences can be mutually exclusive and one evidence being false doesn't necessarily proves that another evidence is true. I think by taking evidence into account, we are going a bit too far.

OA please.
Top
Master | Next Rank: 500 Posts
Posts: 160
Joined: Sun May 03, 2009 1:17 am
Location: Rourkela/Hyderabad
Thanked: 4 times
Followed by:1 members

by sanp_l » Tue Aug 04, 2009 11:29 pm
Consider these statements:

Ptolemaic theory and copernican theories are inconsistent with each other.
Ptolemaic theory is prooved false.
Because of the inconsistency, copernican theory is considered true.

It's a case of casual assumption, where a theory prooved false is implicating the truth about of the other just because both are inconsistent. E should be the correct answer.
Sandy
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 434
Joined: Mon Jun 11, 2007 9:48 pm
Location: Bangalore
Thanked: 6 times
GMAT Score:600

by viju9162 » Wed Aug 05, 2009 12:38 am
I would go with C... Both the therioes stated does not point to any evidence ..
"Native of" is used for a individual while "Native to" is used for a large group
Top
Legendary Member
Posts: 882
Joined: Fri Feb 20, 2009 2:57 pm
Thanked: 15 times
Followed by:1 members
GMAT Score:690

by crackgmat007 » Wed Aug 05, 2009 10:31 am
OA - E Good explanations.
Top
Master | Next Rank: 500 Posts
Posts: 186
Joined: Sat Sep 02, 2006 7:50 pm
Thanked: 10 times
Followed by:1 members

by ogbeni » Wed Aug 05, 2009 10:33 am
crackgmat007 - Where do you get these questions from? Keep em coming man (or woman) ha ha ha
Top
Master | Next Rank: 500 Posts
Posts: 303
Joined: Sat Aug 22, 2015 10:23 am

by joseph32 » Sun May 15, 2016 8:38 pm
Guys can anyone give a decent reason why C is not right.
Top
Post new topic Post Reply
• Page 1 of 1