 Udayana objects to all these formulations. If an effect were not dependent on its cause for its existence, then it could have occurred at any time, in fact at all times, and thus would lose its occasional nature. In fact, every effect has a temporal limit fixed by its cause, prior to which it cannot exist. The second formulation runs contrary to our perception of the occurrence of an event at a particular spatio-temporal location. The third formulation is unacceptable because the same thing cannot be both a cause and an effect at the same time in respect of the same set of conditions, and because it is not possible for anything to exist before its origination. The fourth formulation is rejected outright for no unreal thing can ever enter into a causal process. The fifth formulation leaves us totally mystified because the proponents of the fortuitous generation thesis have nowhere specified what this nature is by virtue of which an effect can occur without its cause. So we wonder, is this nature different from or the same as the effect? On the first alternative the principle of causality is re-established while the second alternative is unintelligible. If the nature of an effect is the same as the effect and a thing can never be separated from its nature, then it would follow that an existent entity would go on causing its own existence over and over again. This is surely absurd. Philosophically these arguments appear to be pretty convincing, but Cārvāka naturalists may find an ally in quantum physical talk about spontaneous decay of a radioactive element, quantum jumps, and so forth.