A legacy of the Enlightenment was the notion of a divide between the natural and supernatural. Miracles can only happen if God intervenes in the natural world.
There was a nice discussion of these issues in a podcast episode, The Intelligible Universe, where John Dickson has a discussion with Peter Harrison and two astrophysicists, Sarah Sweet and Luke Barnes.
[Aside: It was a treat for my wife and I to be in the audience where this episode was recorded live in Brisbane earlier this year.]
Peter Harrison recently published Some New World: Myths of Supernatural Belief in a Secular Age
Here is a summary of one of the relevant chapters
This chapter gives an account of the origins of our present understanding of the natural/supernatural divide, showing how the terminology of the ‘supernatural’ first emerged in the Middle Ages and gradually assumed its modern form between the seventeenth and nineteenth centuries. The attendant ‘isms’—naturalism and supernaturalism—arrive at the end of this period, during the 1800s. The original context for the naturalism/supernaturalism distinction was neither science nor philosophy, but the sphere of biblical criticism. From there it was imported into a scientific context. The nineteenth century also witnessed attempts to reconstruct the history of science with a view to arguing for a long-standing alliance between naturalism and science. A more accurate portrayal of the relevant history shows, to the contrary, that ‘science’ had been consistently aligned with theistic assumptions about the regularities of nature. These regularities were formalised as laws of nature in the seventeenth century, at which time they were understood as divinely authored imperatives to which nature necessarily conformed. In the nineteenth century, what had originally been understood as expressions of the divine will were simply redescribed in purely naturalistic terms by advocates of naturalism. Ironically, they were now claimed to represent evidence against theistic readings of nature.
In the episode, John Dickson makes the following provocative argument.
Jesus probably didn't believe in miracles. Jesus probably didn't believe in the supernatural. If what we mean by supernatural and miracle is the invasion of an outside alien force into nature, that definition of course comes from the enlightenment.
It assumes a dualism, a spiritual ethereal world and the physical one. And every now and then the spiritual injects itself into the material. The gospel writers didn't share this outlook from their viewpoint, which was really the Jewish viewpoint. There aren't two worlds. There's just one world. There is just the creation that comes from the creator.
Everything that happens in the universe from the regular rising of the sun to the very surprising sight given to the blind person. It's all the powerful Work of the one creator working in and through nature. What we call miracles are not invasions from a parallel world. They are just powers, God's powers in and through creation.
And this is why the gospels describe Jesus baffling deeds, not as supernatural events, not even as miracles. They see them as special examples of power. And as signs of the future. The Greek terms in the Gospels are Dunamis, which means strength or power, and Semea, which means sign. Powers, that's easy enough to comprehend.
But what about signs? What are they signs of? It'd be tempting to think that what Jesus means when he describes his powers, his healings, his signs, that what he means is these are signs of the spiritual world. If only you could pull the veil, you would see a spiritual world invading the natural. But actually that's not what Jesus says.
He says they are signs from the future. They are little displays in the present of God's intentions with all of creation...
Don't portray a supernatural world as distinct from a natural one. There is just one world, God's world, where the creator acts powerfully in every moment, and wherein the moments of Jesus healings, the creator gave a preview that one day he will mend all things.