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