Duhem adopted an instrumentalist view of science. He gave his name to the Quine-Duhem thesis, which holds that for any given set of observations there are an innumerably large number of explanations. Thus empirical evidence cannot force the revision of a theory. He further observed that the failure of a theory to make accurat predictions implies a failure of the theory as a whole, not of a particualr part. These views were later adopted by W. V. Quine.
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External Reference
Pierre Maurice Marie Duhem By J J O'Connor and E F Robertson available at http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Duhem.html