Duhem problem

From $T\wedge A\Rightarrow E$ and $\neg E$, infer only $\neg T\vee \neg A$. A failed prediction therefore does not logically isolate failure of the target $T$ from failure of auxiliary hypotheses $A$. Independent calibration and varied experiments can discriminate packages; the logical ambiguity does not imply that every package is equally supported.^[ref]