Imagine a fantasy universe in which both natural and supernatural events take place. There is a set of scientific laws running in the universe, and most events take place as a direct consequence of these scientific laws. Yet at the same time, on rare occasions, there are events which take place without any natural law causing them at all. They happen magically.
Now let’s imagine a group of scientists in this universe who insist that there are no supernatural events. There are merely natural events we do not yet understand. Faced with a supernatural event, they will look for an explanation in terms of natural law.
Suppose that in this universe, Joe is walking to school one day and throws an apple seed on the ground. Suddenly, the seed sprouts and grows into an apple tree in the space of 10 seconds. Will this convince the scientists that supernatural events happen? Surely not.
There are two cases.
First, perhaps the scientists will manage to come up with an explanation for the rapid growth of the tree in terms of natural events. People are clever. We can come up with all sorts of explanations for how things might have happened, whether or not they really happened that way, and certainly there are ways to explain the tree. (For example, we can simply claim that Joe hallucinated or that he fabricated his story.) Obviously, having come up with such an explanation, they will refuse to believe that anything supernatural happened.
Second, the scientists will fail to come up with an explanation in terms of natural events. Will they say, “I guess there are events which cannot be explained naturally”? No, of course not. What they will say is, “We don’t know why this event occurred, but we know things like this don’t happen without a natural cause of some kind. One day, scientists will be able to explain this.”
That’s a little troubling. Apparently, if someone believed that all things are caused by natural law, but lived in a universe in which some supernatural events took place, he would never be able to be persuaded by evidence that he was wrong. Science helps us distinguish between two different naturalistic explanations, and decide which is better, but it seems incapable of even recognizing events that are not the result of natural laws.
There are three reasons that I first became interested in philosophy. One of the three is that I want to understand the meaning and limits of the scientific method. If there is a God and there are miracles (as I believe there are), then what is the proper role of science?