Over the past quarter-millennium much ink has been spilled over the question "Are miracles possible?", or more precisely for the purposes of the biblical scholar, "Are biblical accounts of the miraculous possible?" Sadly much of this ink has generated more heat than light, in large part due to a recurrent sophistic move on the part of the various writers. If miracles are defined, as they often are, as the impossible then, no, miracles are not possible. Indeed, the question, under such conditions, would in fact be "Is the impossible possible?" To this, again, the answer must be "No," but a "No" so trivial that it tells it absolutely nothing about the world in which actually live.
More to the point, the question as formulated completely misunderstands the Weltanschauungen of the biblical writers and the succeeding Christian tradition. The claim was never, at least not until the rise of a mechanistic worldview, that miracles were instances of the impossible but rather that we live in a world wherein such phenomena are possible given the proper condition. The proper condition, of course, was that the God of Israel willed that the phenomena would occur. This was understood as "supernatural," certainly, but not in the sense of violating invariant natural laws, for quite simply that's not how people thought about the world. It was supernatural in the sense of a graced nature; or, more precisely, since all nature, as God's creation, is an instance of divine grace, a miracle is simply a particularly notable instances of said divine.
The miraculous as the violation of invariant natural laws is really a product of Newton and the gang. It's basically inconceivable before the 17th century. It is however a latter-day development of classical thinking, which sought the invariable and necessary. Indeed, Newton and Leibniz represent the zenith of such thinking, with calculus translating into mathematical precision the scattered observations of centuries regarding the constancy of change in the world. It sought to offer an invariant account of the variable, and thus reached the limits of thought that is focused upon the invariant.
As I discussed in a recent post, Lonergan argues that classical thinking began to give way to statistical thinking, i.e. the transition from statements taking the basic form "Y invariably follows X" to statements taking the basic form "Y frequently follows X, but sometimes Z will occur instead." With this breakthrough in human cognition such fields as the human sciences, biological evolution, and quantum physics open up for investigation. And also opens up a new definition of the miraculous, one that is not rooted in an outdated notion of nature as invariant: a miracle is a phenomenon at gross variance from what can be statistically anticipated to be the case given our current understanding of the universe.
Such a definition does not stack the deck by a priori defining out of possibility the miraculous. It also respects that the problem of the miraculous is not first and foremost an ontic matter but rather an epistemic one: it stems from the difference between our understanding of the universe and those of the ancients through the medievals. It further focuses upon phenomenon rather than cause, again to avoid stacking the deck: after all, if the miraculous is defined as God's intervention in the natural order and if one holds that God does not exist then one must rule out in advance the possibility of the miraculous; but, such metaphysical fiat holds little water in actual exegetical and historical investigation, and when it comes to asking about the biblical traditions that is exactly where the issue of the miraculous takes us.
For, as intimated at the beginning of this post, what is really at stake in these discussions is the intelligibly of the biblical account. Note that I said "intelligible," not "veracity." The question in the first instance is not "Are these accounts historically plausible?" or "Did the events happen?" but rather "Are the accounts intelligible?" Certain (but far from all) thinkers during the Enlightenment declared the accounts prima facie absurd, the product either of deliberate fraud or an infantile inability to discern reality from fantasy. Obviously one should approach the writings of fraudsters or man-children differently than one approaches the writings of intelligent, reasonable, and responsible adults, even if one needs to recognize that intelligence, reason, and responsibility are themselves variant across the history of the human species. That is, precisely due to the intelligent, reasonable, and responsible investigations carried out by previous generations each generation operates at a different "level," such that it no longer intelligent, reasonable, and responsible to affirm that which was intelligent, reasonable, and responsible to affirm. Lonergan refers to this as operating "at the level of our times. It is, of course, a foundational idea, a necessary corrective to the sort of anachronism that breeds the sort of sophistry that is the question "Is the impossible possible?"