There Is No Such Thing as the Supernatural
Atheists say something in debates that I wish they would stop saying: science cannot deal with the supernatural. It is offered as modesty — we only do the natural world, the other realm is not our department — and it is received by the believer as a gift, because it concedes the one thing he most needs conceded: that there is another realm.
There is not. The word does not name a category. It names a mood, or a gap, and both of those already have better names.
Lightning Was Supernatural
Consider what has counted as supernatural over time.
Lightning was the weapon of a god. It came from the sky, it killed without touching, it obeyed no rule anyone could state. Then it was understood as an electrical discharge, and it became natural. Nothing about lightning changed. Our description did.
Magnetism acts at a distance, invisibly, on some things and not others; it was occult for most of history and is now a school topic. Disease was demonic possession or divine punishment; it is now microbes. The motion of the planets was the will of intelligences; it is now gravitation. In every case the thing was filed under "supernatural" for exactly as long as it was unexplained, and refiled the day it was not.
The boundary between natural and supernatural has moved in one direction only, every time it has moved. A category whose membership is defined by our current ignorance, and that empties as ignorance retreats, is not a category of things. It is a category of questions we have not yet answered.
The Two Things the Word Means
When someone uses the word today, they mean one of two things, and neither survives being stated plainly.
Something that inspires awe, acts at a distance, or violates everyday intuition. By that standard general relativity is supernatural: mass tells space how to bend and space tells mass how to move, with no rope between them, and time runs at different rates on different floors of the same building. Quantum mechanics is more so. These are the most thoroughly natural phenomena we know, in the sense that they are measured to a dozen decimal places, and they are stranger than anything in any scripture. Awe is not a property of the object. It is a property of the observer's expectations.
Something we cannot currently explain. Fine — but then say that. "We cannot yet explain this" is an honest sentence with a clear meaning. "This is supernatural" adds nothing to it except the implication that it will never be explained and that a different kind of investigation is needed, and neither implication has ever once been borne out.
The Realm That Cannot Be Investigated
The believer's picture is of two domains: the natural one, which science handles, and a supernatural one, which it cannot reach and in which God, souls and miracles reside.
Ask what it would mean for something in the second domain to matter to us. It would have to affect the first domain — answer a prayer, heal a body, move a mind, raise the dead. And anything that affects the natural world is detectable in the natural world, by definition. A miracle that cured a disease would show up in the recovery rate. A God who answered prayers would show up in the prayer studies, and I have written about what those found.
So either the supernatural realm touches ours, in which case it is investigable and the word is doing no work, or it does not, in which case it makes no difference to anything and the word is doing no work. There is no third option in which the realm is real, consequential and permanently beyond inquiry. That is not a limit of science. It is a description of what "real and consequential" means.
What Atheists Should Say Instead
The concession "science cannot address the supernatural" grants the believer a protected territory and then apologises for not entering it. Every argument after that is conducted on his ground.
Drop it. There is one world. Some of it we understand and most of it we do not, and the parts we do not understand are not a different kind of thing — they are the same kind of thing, not yet understood, exactly as lightning was. Claims about God, souls and miracles are claims about this one world. They can be checked to the extent they say anything, and to the extent they say nothing, they are not claims.
The word "supernatural" was invented to mark the edge of what people knew. It still does. The edge is just a great deal further out than it was, and there has never been anything on the other side of it but more of the same.