 To this objection, Dharmakīrti, and especially the later commentators like Śāntarakṣita and Kamalaśīla, reply that if a would-be cause remained unchanged over time and if it was only the concomitant circumstances that changed, then it would have to be the new circumstances that were the actual cause of the new effects. After all, the permanent thing would be present unchanged both when the new effects are present and when they are absent. This failure of the co-presence and co-absence (anvayavyatireka) conditions for determining cause and effect would show, for Dharmakīrti, that the ever-present thing is not the actual cause of the new developments, but that something else is. This is not unreasonable. If an epidemiologist, for example, found that certain factors had been constant for quite some time before the outbreak of an infectious disease and remained unchanged at the time of the outbreak, he would tend to discount them as being responsible for the epidemic. And if he found that some new powerful factors immediately preceded the outbreak, he most likely would pin the causality on them rather than on what had remained constant all along. The logic in these arguments against permanence can be generalized to various would-be entities, including notably the non-Buddhist idea of the permanent creator God (īśvara) who remains the same throughout time while supposedly producing a series of effects.