If this theory is correct, we will observe X. We observe X. Therefore, this theory is correct. Concluding or assuming that a theory is true because of a prediction it makes being observed is invalid. This is one of the challenges of applying the scientific method though rarely is it brought up in academic contexts as it is unlikely to be of consequence to the results of the study. Much more common is questioning the validity of the theory, the validity of expected the theory to have predicted the observation, and/or the validity of the observation itself. See also Abductive reasoning Appeal to consequences Confusion of the inverse Denying the antecedent Fallacy of the single cause Fallacy of the undistributed middle Modus ponens'' Necessity and sufficiency References Propositional fallacies Fallacies Logic articles needing expert attention