A miracle being that which is outside the laws/rules of nature? but how can such a thing be? It seems to be a concept very dependent upon how strogn and firmly one feels that their understanding of nature is, and how far that understanding goes. Hume's problem of nature's uniformity seems very relevant here - What makes one think that he or she has an adequate grasp of what nature can and does do? And if one has a perfect grasp of what nature can do today, why should they think that grasp will be perfect tomorrow? I find the denial of "miracles" to be founded on an illogical inductive inference (but then again, so are affirmations of miracles)
Theoretical example: the laws of quantum mechanics tells us that if one throws a penny at a slab of concrete one inch thick, there exists a non-zero probability that the penny will just go right through. Not "bust" or push through, but GHOST through as if the concrete slab was a hologram or some opitcal illusion. However, this probability is SO low you could repeat the experiment repeadedly for several thousand lifetimes and not have it happen.
Now, let's say, one day someone tries this experiment, and it happens. And they have it on video, verified as being legit and all that good jazz.
The rhetorical question to ask is: Could this have been a miracle? Quantum Mechanics tells us its possible, but extraordinarily unlikely. Is it more likely that this event was "outside" the laws of nature, or that something else is going on? Did nature "flip out" when the penny went through the concrete, or was this that one event in 10^-58 (or whatever the P is) that QM tells us can happen?
As a pragmatist, I see the word "miracle" as a kind of label when a particular event seems so off the wall or absurd that it's simply too much of a stretch to link it to what one conceives as within the laws of nature. It all depends on how far and broad one wishes to place the explanatory power of the "bounds" of nature, if there is such a thing. Obviously, those that believe in miracles think there is a bound to nature and there are events observable to us that are outside it.
me? I'm not convinced nature has any bound - it has tendancies, not limits. A miracle is just an X-file in the filing cabinet of "nature's tidings".