• Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • examPAL
    Most awarded test prep in the world
    Now free for 30 days

    Available with Beat the GMAT members only code

    MORE DETAILS
    examPAL
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep

theory is either true

This topic has 1 expert reply and 1 member reply
sogmat Master | Next Rank: 500 Posts Default Avatar
Joined
21 Oct 2008
Posted:
113 messages
Upvotes:
1
Target GMAT Score:
720+

theory is either true

Post Thu Dec 18, 2008 9:35 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

OA ([E][/spoiler]

  • +1 Upvote Post
  • Quote
  • Flag
Post Mon Oct 30, 2017 10:41 am
The conclusion: Galileo's observations of Jupiter's satellites proved the truth of the Copernican theory.

The evidence: 1) A theory is either true or false.
2) Galileo's observations of Jupiter's satellites showed that the Ptolemaic theory of the motion of celestial bodies is false.
3) the Copernican theory of planetary motion is inconsistent with the Ptolemaic account.

We know that Ptolemy was wrong. We know that Copernicus is inconsistent with Ptolemy. That doesn't mean that Copernicus was correct.
Let's say Dane thinks that 2 + 2 = 5. We know that Sal's opinion is inconsistent with Dane's on this subject. That doesn't mean that Sal is correct. He might think 2 + 2 = 13. Dane and Sal are inconsistent with each other, but they're both wrong. Of course, Sal would be correct if he did know that 2 + 2 =4, but we don't know that. We also don't know what Copernicus thinks, and we can't assume what he thinks. Ptolemy and Copernicus could be inconsistent with each other (which would have been a better way of wording Choice E) and still both be wrong.

Choice A brings in a number of irrelevant pieces of information.
Choice B doesn't add anything new.
Choice C does not need to be assumed. They could have reached different conclusions based on the same evidence.
Choice D is irrelevant background information.

I'm available if you'd like any follow up.

_________________
GMAT Prep From The Economist
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.

  • +1 Upvote Post
  • Quote
  • Flag
Free 7-Day Test Prep with Economist GMAT Tutor - Receive free access to the top-rated GMAT prep course including a 1-on-1 strategy session, 2 full-length tests, and 5 ask-a-tutor messages. Get started now.
Post Sat Oct 21, 2017 3:03 pm
I don't understand it. Can any explain this please.

  • +1 Upvote Post
  • Quote
  • Flag

Best Conversation Starters

1 lheiannie07 112 topics
2 Roland2rule 74 topics
3 ardz24 67 topics
4 LUANDATO 53 topics
5 swerve 47 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

155 posts
2 image description Jeff@TargetTestPrep

Target Test Prep

106 posts
3 image description Rich.C@EMPOWERgma...

EMPOWERgmat

100 posts
4 image description Scott@TargetTestPrep

Target Test Prep

98 posts
5 image description EconomistGMATTutor

The Economist GMAT Tutor

89 posts
See More Top Beat The GMAT Experts