Pan-Mentalism and Geometry
Russell’s neutral monism is enjoying something of a recrudescence. He starts with the thought that physics does not disclose the intrinsic nature of matter, being merely structural and relational, and then postulates that this nature is mental in character. That is, the intrinsic nature of matter is not known through physics, so there is a gap in our knowledge of the physical world; but we can fill this gap with a philosophical conjecture, to the effect that the so-called physical world is really a mental world. Thus we (a) solve the problem of the intrinsic nature of matter and (b) solve the mind-body problem as a corollary. Russell calls this theory “neutral monism”, though it not very neutral but clearly idealist; others have called it “panpsychism” or “panexperientialism” (Eddington and Whitehead also espoused the theory at roughly the same time as Russell). I prefer the term “pan-mentalism” for stylistic reasons (with the hyphen). I will present an objection to the theory that I have not seen made before (there are several other well-known objections).
Let’s call whatever it is that constitutes the underlying nature of matter M. It used to be said that M is a type of substance or a type of stuff—something real and concrete, if very general (everything physical is made of the same substance). M is traditionally contrasted with whatever it is that constitutes the underlying nature of mind, which we may call P. P must be suitable for sustaining the distinctive properties of mind—in particular, thought(according to the Cartesian tradition). M by contrast must be suitable for sustaining the distinctive properties of matter: it must be capable of having such properties. What are these properties? Chief among them are properties of extension: shape, size, spatial location, and measurability. So M must instantiate the properties characteristic of extension: for example, M (or a piece of it) constitutes a cubical object resting on a table with sides measuring 1 meter. It is a given that M has just such geometrical properties—since that is what a material thing is (as well as mass, charge, motion, etc). Nothing could be M and yet lack a geometrical form (a spatial nature). We may not know much about the ultimate nature of M, but we do know that it must be geometrical. Anything of the nature of P could not be M, since P is by definition not extended—the immaterial substance can’t be the material substance.
But now, according to pan-mentalism, the intrinsic nature of matter is mental—consciousness itself on standard views. The “stuff” of the world is experiential—conscious experience of some type. How can this stuff be geometrical? How can experiences be cubical or 1 meter wide or rest on a table? How can instances of consciousness have a spatial nature? In particular, how can they have the spatial nature of ordinary physical objects? A solid cubical object sits on a table, and this object is said to be completely (intrinsically) experiential in nature: how can that be? Experiences can’t form cubes! Minds have no such geometry. Yet they must have geometry if M is mentally constituted, since M is inherently geometrical. Pan-mentalism entails that some (most) mental particulars have the geometry of the ordinary physical world. The objection, then, is that no such thing is possible; therefore, pan-mentalism must be false. Whatever M is it must be possible for objects constituted by M to have properties of extension, but mental things necessarily lack such properties, so they cannot constitute M. That is, matter can’t be mind, given that matter is geometrical and mind is not. The nature of matter can’t be a mental nature.
It might be replied that this argument is based on the assumption that all mind resembles our mind: why should we accept that everything mental is non-geometrical just because human mentality is? The tracts of mind that constitute matter are geometrical, it will be said, even if our minds are not: this is simply an entailment of the theory, one that we should learn to accept. But the trouble with this move is that the components of the cosmic mind are supposed to constitute the kinds of minds with which we are familiar, and so those minds would have to be geometrical too. How could the geometry of the cosmic mind, latent in all of physical nature, magically disappear when mental elements are combined to form human minds? If the micro mental components that form macro minds have shape and size, then so will the macro minds themselves. Then let it be: pan-mentalism entails that our minds are geometrical—just like our brains—so why not accept that consequence? It might accordingly be held that the geometry of the mind is the geometry of the brain. True, it sounds odd to talk this way, but (it may be said) it is a consequence of the theory we just have to accept: contrary to the appearances, ordinary minds have ordinary spatial geometry. It may not seem so to the introspective eye, or to commonsense psychology, but there are plenty of cases in which sound scientific theory has contradicted the appearances. We have discovered that our consciousness has a spatial nature, despite our commonsense prejudices.
The trouble with this particular piece of bullet biting is that it is hard to see how we could not know this spatial nature given that we know our own minds. If consciousness has a spatial nature, how can we be blind to it? Shouldn’t we have been onto it long ago? We know that matter has a spatial nature, since this is evident from observation of instances of matter, so why don’t we know that mind has a spatial nature, if that is indeed what it has? It has such a nature no less than matter does, and we can know our own minds, so why does it escape our attention? We ought to know it from the start, not as the result of elaborate philosophical argument. Yet we don’t: this is very strange, to say the least. What we really have is a reductio ad absurdum of the theory that the unknown nature of matter is constituted by a mental reality. For once it is noticed that this requires that the mental be geometrical, we are led to the conclusion that our own minds must be geometrical and known to be so—but this is not the case. The only way out is to insist that our minds really are thoroughly geometrical, no less so than ordinary physical objects, but that we are unaccountably ignorant of this fact. My current visual experience of a red ball is really star-shaped and 3 centimeters wide, but I am oblivious to this fact. But why should I be so oblivious, and what would it even be to have a star-shaped experience (as opposed to an experience of a star-shaped object)? We thus have to reject the initial assumption that matter has a mental nature. Pan-mentalism is false.
Russell’s starting-point was that we don’t know the intrinsic nature of matter, only its relational-extrinsic structure. He then conjectures that this nature is experiential. It turns out that the theory faces a problem deriving from the geometry of matter, as just outlined. But there is still the question of what the intrinsic nature of matter might be. We know that it is not mental, on pain of geometrizing the mind, but we have no positive idea of what it is. All we know is that, whatever it is, it must be capable of geometrical form. Whether there is any other available theory that answers the question remains to be seen. Of course, if pan-mentalism is demonstrably false as a theory of what matter is, then it cannot provide a solution to the mind-body problem. However, it may be that the unknown nature of matter is relevant to the mind-body problem, possibly because both the known structure of matter and the mind result from it in some way we don’t comprehend. There may be some sort of hidden unity to the universe at its deepest level. All I have argued here is that this deepest level cannot be mental in any sense that we can recognize.