Atheist Science of the Gaps The postponement, with a expectation of a secular Answer, with the hope of a future scientific discovery is the imposition of a Science of the Gaps on the discussion of Miracles. It is also a Statement of Faith, which thing most atheists denegrade with vigor. It seems that Atheists engage in faith as much as theists after all.
In fact, an atheist can't engage in communication without admitting the existence of order and intelligence in the Universe. Chance produces nothing. "Chance" has no creative power; it is just an abstract mathematical statement.
Just to form a sentence, with the right sequence and order of syntax, requires intelligence...a thought process beyond the chance formation of purely physical reality. And in addition, the mathematicians, John Lewis and Albert Einstein acknowledged the orderly mathematical nature of the universe that required the existence of a Super Mathematician over all.
Requirements So how can one discern beyond a reasonable doubt that Christian miracles happen?
(1) The alleged Miracle must be done in conjunction with the Name of Jesus specifically. Without this foundation any supernatural action is left floating in the air of uncertainty, and is open to being credited to happenstance.
(2) The "time context" must be sufficient. In other words, if a person commanded someone to be healed, and waited for years to have his happen, there is no rational reason to explain it as a miracle.
However, as Jesus was known to do, when someone is approached with commands of healing and immediately the person is made whole, it is very reasonable to conclude that it is a Miracle! "Time and chance" played no part in the event. Many times the Holy Bible recorded the fact that eye-witnesses saw this occurring (especially parents), and they confirmed the miracle. Some were encouraged to "show themselves to the priest (doctor)" for confirmation.
[This does not rule out "progressive miracles" in history (past or present), but for sake of this Question, we limit ourselves.]
(3)There must be empirical verification. If a person born blind, claims healing in Jesus name, it would be logical to test his eye-sight. This could not be faked, especially if he was known around town, and the people saw him in that condition. A paralized or lame man could confirm his healing by walking. In fact, a dead man (known to be dead for three days, and not in a coma) could exhibit the miracle of Resurrection by not just showing himself alive, but by "eating and drinking" with the observers...as well as talking, etc. (His death would have to be beyond doubt. For example: He stinketh! Or he was executed by a trained executioner, and certified dead.)
Presuppositions The problem with accepting the fact of the miraculous is not so much lack of evidence, but rather the Presuppositions one has before miracles are discussed. If one's presupposition of existence (or worldview) is a secular philosophy, or naturalistic, or atheistic (agnostic), then no matter the evidence he is locked in a walled cell by the key of a closed mind. Logically speaking, he is committing the Fallacy of Logic called, begging the question.
It is so important, therefore, to examine one's Presuppositions. Or at the very least, hold them in abeyance momentarily, and do research to see if another worldview better fits the facts of reality (answers the Existential Questions of life adequately.).
A miracle just might be in the offing! A new eye-sight! A new insight!