Another definition of miracle is “an event impossible to explain by natural
causes.” This definition is inadequate because (1) it does not include God as the one
who brings about the miracle; (2) it assumes that God does not use some natural
causes when he works in an unusual or amazing way, and thus it assumes again that
God only occasionally intervenes in the world; and (3) it will result in a significant
minimizing of actual miracles and an increase in skepticism, since many times when
God works in answer to prayer the result is amazing to those who prayed but it is not
absolutely impossible to explain by natural causes, especially for a skeptic who
simply refuses to see God’s hand at work.

Colin Brown critic

Colin Brown says regarding Hume thinking that we should think of nature as fixed - have faith in fixed nature not miracles, “To his credit, it has to be said that Hume sought to establish his worldview. But once established, nothing was allowed to change it. It acquired a quasi-religious character beyond further verification and falsification, because no fact could be admitted that could conceivable count against it [i.e. miracle]. It has to be said that worldviews. . . are not disproved by single facts. Their validity and usefulness lie in their capacity to account for the world we live in. . . . in the field of science, when an existing view is so beset by anomalies and qualifications that a change is needed, there occurs. . . a paradigm shift involving the adoption of a new frame of reference.”

A single fact does refute a worldview if it is magical.  For example, if only good miracles happen then a bad one proves this is not true. The reason is that the worldview is based on something that is bigger than anything in the universe and is much in the atom as in the whole solar system.

Hume says that a miracle violates what our larger experience confirms as something that does not happen. It is like how most rocks do not float into your garden but if one did you can refuse to believe it happened.  It is like how you ignore a cutting comment from the nicest ever.  He is said to call testimony to a miracle unreliable. But  he means not that it is unreliable but that it is shouted over by a stronger voice!