 Recent debates regarding the legitimacy of different lines of research in cosmology reflect different responses to this challenge. One response is to retreat to hypothetico-deductivism (HD): a hypothesis receives an incremental boost in confidence when one of its consequences is verified (and a decrease if it is  falsified).[58]  Proponents of inflation argue, for example, that inflation should be accepted based on its successful prediction of a flat universe with a specific spectrum of density perturbations. Some advocates of the multiverse take its successful prediction of the value of \(\Lambda\) as the most compelling evidence in its favor.