Methodological naturalists don't wonder about miracles. They write off anything that looks like fulfilled prophecy or answered prayer as "coincidence." They dismiss anything that seems to be a miracle as fraud or myth. That's makes it easy to maintain their precommitments to a merely material world, but it's their metaphysics, not good science, that explains such behavior.
What happens when a methodological naturalist encounters some data point that doesn't fit his preconceptions? The objective scientist of our cultural ideal would stop, look, and listen. He (or she) would furrow his (or her) studious brow, roll up the immaculate sleeves of his (or her) venerable lab coat, and subject his (or her) previously held theories to revision in light of new evidence. But, as Thomas Kuhn explained in The Structure of Scientific Revolutions, that's hardly ever what happens.
Consider how "science" deals with just one uncooperative example. Isaiah 38:1-6 says:
In those days Hezekiah became sick and was at the point of death. And Isaiah the prophet the son of Amoz came to him, and said to him, “Thus says the Lord: Set your house in order, for you shall die, you shall not recover.” Then Hezekiah turned his face to the wall and prayed to the Lord and said, “Please, O Lord, remember how I have walked before you in faithfulness and with a whole heart, and have done what is good in your sight.” And Hezekiah wept bitterly. Then the word of the Lord came to Isaiah: "Go and say to Hezekiah, Thus says the Lord, the God of David your father: I have heard your prayer; I have seen your tears. Behold, I will add fifteen years to your life. I will deliver you and this city out of the hand of the king of Assyria, and will defend this city.
The methodological naturalist deftly deals with this report by just saying, "It never happened." Denial tends to be our first line of defense. This doesn't prove methodological naturalism to be wrong, but it ought to raise an eyebrow.
Methodological naturalists generally dismiss the Bible stories as naive credulity. The problem with that approach is that these tales weren't told by idiots. The prophet Isaiah was a Hebrew noble who wrote one of antiquity's loftiest works. The story is rich in specific details that make it sound more like history and less like myth. Isaiah took a cake of figs and applied it to the boil that was killing the king, which seems to have made a difference. Hezekiah did get well, and he lived for fifteen years.
The next defense is "mere coincidence." So what if Hezekiah lived, the naturalist asks. For every good guess there are a million failures that fall on their face. In this model, Isaiah just got lucky.
That's hard to square with the rest of the story. Hezekiah was no fool. He wanted proof of Isaiah's prophecy, and he got it. Hezekiah asked for a sign that he would get well, and the sun's shadow went backwards ten steps.
That leaves two more avenues of escape for the pre-committed naturalist. Either the whole story was a myth, or Isaiah was a fraud. There are problems with both answers. A moving shadow is not what you'd expect from a myth--in a made-up story, a great dragon would appear in the sky, or God might speak out loud. A shadow seems too mundane for any myth.
The moving shadow would make sense if Isaiah was a fraud--it's the kind of hoax an illusionist might contrive with mirrors. But nothing in the rest of Isaiah's record suggests he was anything like that kind of "court magician." Nothing in the story itself demands such proof--when Hezekiah asked for proof that he would get well, Isaiah could have just as easily told him to "wait and see."
Is this the best that naturalism can do? Not even remotely! It is possible to take Isaiah seriously without giving up on science. A "naturalistic" explanation fits the facts as well as any other. An experienced doctor might argue that the poultice of figs and the moving shadow were both essential means to the same cure. Hezekiah had a "boil" which wasn't getting better. The Hebrew term isn't specific enough to know what that meant, but any infection was a serious problem before the discovery of antibiotics. To make things worse, he had turned his face to the wall and wept bitterly--that's a biblical term for what we might call "terminal depression."
Isaiah directly addressed the physical and the psychological aspects of Hezekiah's condition. The fig plaster had some effect on the infection in the boil--perhaps enough to give Hezekiah a fighting chance at life. But that doesn't do much good unless the patient is willing to fight. Isaiah's promise (plus the shadow on the steps) could have helped Hezekiah find the faith he needed to struggle back from the brink.
What does this tell us about the shadow on the steps? Nothing--except that we don't have to dismiss it as myth, discount it as a hoax, or reverse the rotation of the planet. The Bible says the shadow went backwards on the steps and Hezekiah got better. This passage in Isaiah would be good history and sound theology with or without a "scientific explanation." Maybe both things happened by the unmediated intervention of God. Maybe both had natural explanations--the osmotic pressure of a sugary paste, an unusual formation of the clouds. The story shows God's glory either way.
Which brings me to my point: the believing Christian can accomodate science more easily than the methodological naturalist can accommodate history. Twenty-first century Christians can't evade the laws of physics, so they must adjust their paradigm or isolate themselves from the broader culture. Modern materialists, by contrast, ignore any evidence they don't like. In the short run, that gives materialism an edge--but truth outperforms popularity in the long run. Any future metaphysics that deserves the name of science will take all the available evidence seriously, not just the part that fits our preconceptions.