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# A theory is either true or false. Galileo's observations of

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VP
Joined: 22 Aug 2005
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A theory is either true or false. Galileo's observations of [#permalink]

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20 Dec 2005, 00:02
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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. who ever 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
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Intern
Joined: 29 Nov 2005
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20 Dec 2005, 00:39
VOTE FOR E~

A theory is either ture or false,

We have G's evidence and two theory P theory and C theory

P is a theory ---> it could be ture or false

P theory is reject by G's evidence. thus ---> P is false

But the refutation of P is nothing to do with theory C.

therefore C still could be ture or false.

However, if we add an assupution, namely E, to the line of reasoning presented above.

E says: the Ptolemaic and Copernican theories, being inconsistent, cannot both be false
that proposed an either-or situation
1) P ture, C false
2) P false, C ture

Given the conditions we have

P ---> false P theory is reject by G's evidence.

thus we get 2) P false, C ture

So E is needed as long as the arguement hold---> Assumption

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Director
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20 Dec 2005, 03:14
I agree to E

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VP
Joined: 22 Aug 2005
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21 Dec 2005, 18:13
OA is E.
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Whether you think you can or think you can't. You're right! - Henry Ford (1863 - 1947)

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21 Dec 2005, 18:13
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# A theory is either true or false. Galileo's observations of

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