Galileo Vs Copernicus:Tough

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 217
Joined: 10 Jan 2010
Thanked: 7 times
Followed by:1 members

Galileo Vs Copernicus:Tough

by zaarathelab » Fri Nov 18, 2011 3:24 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
Success = Max(Hardwork) + Min(Luck)

User avatar
Master | Next Rank: 500 Posts
Posts: 296
Joined: 29 May 2011
Location: Vietnam
Thanked: 10 times
Followed by:5 members

by tuanquang269 » Fri Nov 18, 2011 4:02 am
I choose E

User avatar
Legendary Member
Posts: 1101
Joined: 28 Jan 2011
Thanked: 47 times
Followed by:13 members
GMAT Score:640

by HSPA » Fri Nov 18, 2011 6:18 am
IMO E.. Option C weakens the argument

Assumption explained in a dry manner:

A proved B as a bad guy.
C opposes B, => A&C are good friends

Assumption: majority is always right.
First take: 640 (50M, 27V) - RC needs 300% improvement
Second take: coming soon..
Regards,
HSPA.

Legendary Member
Posts: 627
Joined: 23 Jun 2011
Thanked: 4 times
Followed by:1 members

by mankey » Sat Nov 19, 2011 1:28 am
Is it B? Please explain.

Thanks.

Master | Next Rank: 500 Posts
Posts: 217
Joined: 10 Jan 2010
Thanked: 7 times
Followed by:1 members

by zaarathelab » Thu Dec 08, 2011 4:09 am
can someone compare C and E?
Success = Max(Hardwork) + Min(Luck)

Master | Next Rank: 500 Posts
Posts: 385
Joined: 23 Sep 2011
Thanked: 62 times
Followed by:6 members

by user123321 » Thu Dec 08, 2011 4:51 am
IMO E

A proves some theory X false
Since B proves the same theory X false, the argument says A proves B true.

E) A & B being inconsistent with X => A,B cannot both be false, which is a questionable assumption IMO,

user123321
Just started my preparation :D
Want to do it right the first time.

Master | Next Rank: 500 Posts
Posts: 242
Joined: 01 Aug 2008
Location: Delhi
Thanked: 6 times

by ranjeet75 » Thu Dec 08, 2011 8:25 am
I think B should be the answer.

What's the OA?

GMAT Instructor
Posts: 1302
Joined: 19 Oct 2009
Location: Toronto
Thanked: 539 times
Followed by:163 members
GMAT Score:800

by Testluv » Thu Dec 08, 2011 9:31 pm
Choice (E) is definitely correct because if both theories CAN be false, the argument no longer stands. This application of the Kaplan denial test proves that (E) is an assumption needed for the argument.

@ranjeet: choice (B) is something that must be trued based on the stated evidence--that is, choice B is an inference not an assumption. In assumption questions, avoid choices that restate evidence or state inferrable evidence.
Kaplan Teacher in Toronto

Newbie | Next Rank: 10 Posts
Posts: 9
Joined: 27 Oct 2011
Thanked: 2 times

by westom » Fri Dec 09, 2011 12:33 pm
zaarathelab wrote: The argument above is open to the objection that it makes the questionable assumption that ...
To have a fact means well proven theory (a hypothesis) must explain it AND experimental evidence must demonstrate it. This was taught in junior high science. Without both, then no fact or knowledge is possible. Observation alone only creates wild speculation.

The observation of motion that was consistent with Copernican theories only says Copernican theory exists; is valid. It says nothing about Ptolemaic theory. According to facts provided, and since three states always exist in reality (true, false, and undefined), then nothing was proven or known about Ptolemaic theory.