Quine Duhem Hypothesis

  

http://en.wikipedia.org/wiki/Duhem%E2%80%93Quine_thesis


"The Duhem–Quine thesis (also called the Duhem–Quine problem, after Pierre Duhem and Willard Van Orman Quine) is that it is impossible to test a scientific hypothesis in isolation, because an empirical test of the hypothesis requires one or more background assumptions (also called auxiliary assumptions or auxiliary hypotheses). The hypothesis in question is by itself incapable of making predictions. Instead, the consequences of the hypothesis typically rest on background assumptions from which to derive predictions. This prevents a theory from becoming conclusively falsified through empirical means if the background assumptions are not proven (since background assumptions sometimes involve one or more scientific theories). For instance, to "disprove" the idea that the Earthis in motion, some people noted that birds did not get thrown off into the sky whenever they let go of a tree branch. That datum is no longer accepted as empirical evidence that the Earth is not moving because we have adopted a different background system of physicsthat allows us to make different predictions." 


-- From Wikipedia