 The general idea is that hypotheses are confirmed when their predictions are borne out. To capture this idea formally in deductive logic, we’re equating prediction with logical entailment. When an object is \(F\), the hypothesis \(\forall x(Fx \supset Gx)\) entails/predicts that the object is \(G\). So any discovery of an object that is both \(F\) and \(G\) confirms the hypothesis.