I get frustrated with those who talk about “naturalism”, the “supernatural”, “materialism”, etc., without defining their terms. And this goes for both the supporters and opponents of science. Why talk about “methodological materialism” and “metaphysical materialism” if you don’t, first, make clear what you mean by this.
“Once again, the point needs to be made that we don’t have clear, agreed, definitions of the words “natural” and “supernatural”. This is not a surprising fact. These are ordinary English words, used on a daily basis in informal discourse. We know that the words used in this way, in ordinary language, are typically quite fuzzy.”
“Discussion of whether science can investigate “the supernatural” often seems to involve one party or another to the discussion assuming that “supernatural” has a clear meaning, when it simply doesn’t. There are various phenomena that are commonly called “supernatural”, but it’s not really clear what they have in common.”
“Perhaps some clear definition of “physicality” or “body” can be given, and people who call themselves “naturalists” can claim to be rejecting the “supernatural” when they reject the existence of minds that are totally without any physicality or embodiment. However, it would be unusual to find anyone who believes in the existence of such “supernatural” minds while claiming that they have no power to influence the physical world in ways that can be sensed. If a “supernatural” mind has the power to interact with the physical world, then we can study it. We can’t study its physical substance, of course, if it has no physical substance, but we can study its powers, its behaviour, perhaps its motivations. Its non-physicality may limit the conclusions we can draw about it, but as long as enough is asserted about what it does we can certainly study whether there is evidence for or against the claim that it exists.
Thus, on one definition of “the supernatural”, it is not beyond science to examine any claims at all about the supernatural.”
“When we say that science deals with the “natural”, while religion deals with the “supernatural” we need to define our terms (reasonably) clearly, then use them consistently. If we define the “natural” so that it means “everything” then it will turn out to be the case that science can deal with whatever turns out to exist, but that tells us nothing about what sorts of things actually do exist. It leaves open the question of whether gods and ghosts exist, for example. If they do, then it suggests that science can deal with them.Whenever we debate what can be investigated by science, whether science and religion are compatible, whether the existence of entities typically referred to by religions (such as gods) can be studied scientifically, and whether those things exist at all, it would be helpful if we made a conscientious effort to use the various terms consistently and to take note of how others define their terms if they bother to do so. This is difficult to do – language is slippery, and a point comes where it is too demanding to cross every single “t” and dot every single “i”. Nonetheless, it is not playing games. It is important that we do this to avoid trapping ourselves in prisons of words, drawing conclusions that are not justified by the facts. It would also help us avoid a lot of distracting emotional attacks that merely make the debate more difficult to keep under control.”
The article is quite helpful – worth reading.