Update: A summary of this article's thesis has been formally published as "On Defining Naturalism as a Worldview" in Free Inquiry 30.3 (April/May 2010), pp. 50–51; and has been formally employed by Yonatan Fishman in "Can Science Test Supernatural Worldviews?" in Science & Education 18 (2009), pp. 813–37.
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There is a trend in science and law to define the word "supernatural" as "the untestable," which is perhaps understandable for its practicality, but deeply flawed as both philosophy and social policy. Flawed as philosophy, because testability is not even a metaphysical distinction, but an epistemological one, and yet in the real world everyone uses the word “supernatural” to make metaphysical distinctions. And flawed as social policy, because the more that judges and scientists separate themselves from the people with deviant language, the less support they will find from that quarter, and the legal and scientific communities as we know them will crumble if they lose the support of the people. Science and the courts must serve man. And to do that, they must at least try to speak his language. And yet already a rising tide of hostility against both science and the courts is evident. Making it worse is not the solution.
As I argue in Sense and Goodness without God (pp. 29-35), philosophy is wasting its time if its definitions of words do not track what people really mean when they use them. And when we look at the real world, we find the supernatural is universally meant and understood to mean something metaphysically different from the natural. I could adduce many examples of the bad fit between real language and this ill-advised attempt at an "official" definition, but here are just two:
- The underlying mechanics of quantum phenomena might be physically beyond all observation and therefore untestable, but no one would then conclude that quantum mechanics is supernatural. Just because I can't look inside a box does not make its contents supernatural.
- Conversely, if I suddenly acquired the Force of the Jedi and could predict the future, control minds, move objects and defy the laws of physics, all merely by an act of will, ordinary people everywhere would call this a supernatural power, yet it would be entirely testable. Scientists could record and measure the nature and extent of my powers and confirm them well within the requirements of peer review.
Consequently, we need a proper definition of "supernatural" (and, therefore, of the word "natural" as well), one that tracks what people really mean when they use the word, one that marks a metaphysical distinction, and allows us to say when the word is being used sloppily or improperly, as must be the case for any word we intend to be useful. This is all the more crucial for metaphysical naturalists, who must define their worldview in some manner that actually makes it meaningfully different from supernaturalist worldviews. Critics of naturalism are entirely correct about this.
I define "nature" in Sense and Goodness without God (on pp. 211-12, with a little help from pp. 67-69). But I explain this in elaborate detail, with considerable supporting evidence, in my Secular Web article Defending Naturalism as a Worldview (2003), to which I referred readers in my book. After this, and the publication of Sense and Goodness, I defined the natural-supernatural distinction even more rigorously in the joint statement of the Carrier-Wanchick Debate (2006). Anyone who wishes to interact with my definitions of natural and supernatural must read these two articles.
In short, I argue "naturalism" means, in the simplest terms, that every mental thing is entirely caused by fundamentally nonmental things, and is entirely dependent on nonmental things for its existence. Therefore, "supernaturalism" means that at least some mental things cannot be reduced to nonmental things. As I summarized in the Carrier-Wanchick debate (and please pardon the dry, technical wording):
If [naturalism] is true, then all minds, and all the contents and powers and effects of minds, are entirely caused by natural [i.e. fundamentally nonmental] phenomena. But if naturalism is false, then some minds, or some of the contents or powers or effects of minds, are causally independent of nature. In other words, such things would then be partly or wholly caused by themselves, or exist or operate directly or fundamentally on their own.
Despite all I have written on this, several people have had difficulties understanding how to apply my construction of these terms, so I thought I'd have some extended fun. Analogies and concrete examples always do a better job getting across to people what we're talking about, so that's what I'm going to do today. With a bit of fantasy, I'll show how my natural-supernatural distinction can be used to tell the difference between a natural and a supernatural explanation (a metaphysical question), and how we can know when one or the other actually is true (an epistemological question). I take a look at supernatural beings, substances, powers, properties, and effects, and we'll get to see what natural explanations of similar observations would look like, and how they would be different.
Before we can get to that, we need to get past one other important distinction: the meaning of paranormal.