We often hear people saying “this research study proved that…” Well, researchers never **prove** anything when testing hypotheses. We do collect evidence that may or may not support our claims. In a well-designed research study in which the null hypothesis (H0) is rejected, all that can be said is that empirical evidence was collected to support the formulated alternative hypothesis.
Karl Popper (as cited here) said, ‘All swans are white cannot be proved true by any number of observations of white swan – we might have failed to spot a black swan somewhere – but it can be shown false by a single authentic sighting of a black swan. Scientific theories of this universal form, therefore, can never be conclusively verified, though it may be possible to falsify them.’