Declension wrote:
If you don't think that a miracle has ever happened, please don't post here. You are not needed.
That would lead to a rather one-sided "debate".
The first and most important thing is to define what a miracle is. Some people would declare the birth of a child is a miracle, in which case miracles are so commonplace that they aren't worthy of discussion. So events of beauty and/or nobility (and children) aside, we have two fairly common definitions:
(1) Highly unlikely occurrences that suggest the work of a higher power.
(2) Impossible occurrences that can ONLY be the work of a higher power.
The problem with (1) is that such "miracles" cannot be proven. In many cases they can simply be coincidences, and not even very unlikely ones. We are very bad with our instinctive sense of probability. One may feel that the grandmother who wins the lottery just when she needs a hip operation has been blessed by a miracle, but the odds are far less astronomical when you consider that there are thousands of grannies out there doing the same thing, not to mention all the other deserving people. You can't throw a dart into a warehouse filled with dartboards and declare the one you hit was the intended target.
There's also the question of whether a miracle is always a good thing. The religiously inclined may argue that they are, but then they fall into a trap of confirmation bias. Since we can't identify the miracles from the coincidences, they can simply categorise "good" things as miracles and "bad" ones as not. There's no way to prove this is correct, but there's no way to prove it wrong either.
As a definition, (1) is pretty useless. Unless God/VIshnu/Allah/Jehovah/FSM can verify they were responsible, of course.
Option (2) is logically contradictory. If something is impossible, it cannot happen. If it happens, it is possible. Miracles of this type are thus either fictitious or entirely possible, given the right circumstances, in which case we're looking at highly improbable. We're back to (1) again.
A better question might be to ask if any particular miracles have happened. I have doubts about all the classic ones.