What is a miracle? Controversy over the conception of a miracle focuses primarily on whether a miracle must be, in some sense, contrary to natural law. Must it, in particular, be a violation of natural law? Supposing that it must be, a second question arises, namely, whether the conception of such a violation is a coherent one.
Philosophers have also been concerned about what sort of observable criteria would allow us to identify an event as a miracle, particularly insofar as that means identifying it as a violation of natural law. How, for example, can we tell the difference between a case in which an event is a genuine violation–assuming that some sense can be made of this notion–and one that conforms to some natural law that is unknown to us? And given the occurrence of a genuine violation, how are we to determine whether it is due to divine agency, or whether it is nothing more than a spontaneous lapse in the natural order?
The second main issue is epistemological: Once we settle on what a miracle is, can we ever have good reason to believe that one has taken place? This question is generally connected with the problem of whether testimony, such as that provided by scriptural sources, can ever give us adequate reason to believe that a miracle has occurred.