Saturday, July 19, 2014

What is a material object?

I've found the notion of a material object very puzzling. Here is something that would render it less puzzling to me:

  • x is a material object if and only if x has limited location.
There would then be three ways for an object y to be immaterial:
  1. There are locations and y has no location.
  2. There are no locations.
  3. There are locations and y is unlimited in location.
It would now be plausible that a perfect being would be necessarily immaterial. A perfect being doesn't need anything other than itself, so it could exist in worlds where there are no locations, in which worlds it would have type 2 immateriality. And in worlds where there are locations, a perfect being would be unlimited in location, and would have type 3 immateriality. Thus, in all worlds, a perfect being would have immateriality. But in no world would a perfect being have type 1 immateriality.

One might worry that there could be an animal that is as big as space itself, and then it would count as an immaterial object. But even though the animal would be everywhere, it wouldn't be everywhere in every part and respect. Its digestive system would be here but not there, and so on.

Alternately, one might stick to our definition of materiality as limited location, but modalize. Maybe "limited location" is a modal concept, so that a being that could be limited in location is thereby limited in location.


Drew said...

That seems a bit counterintuitive. Descartes thought of materiality as equal to extension, but that doesn't seem right. If electrons are point particles, they are not extended, and yet seem to be material.

Conversely, one generally wouldn't think of extended phantasmal entities like ghosts to be material entities, either.

Maybe we can think of materiality in terms of composition.

bethyada said...

I presume you mean location in space? Perhaps this could be extended to time and space?

I like Drew's idea of composition, though this would need to be carefully defined as information is non-material but one could equivocate on composition.

Alexander R Pruss said...


Electrons may not be extended, but they do have location (in a wavefunction sort of way).

There are no ghosts. There are only disembodied souls. If there were a ghost, and it were something over and beyond a disembodied soul, and that something more gave it that phantasmal presence, wouldn't that something more be a ghostly matter?


Yes, I was thinking of space. A purely temporal entity wouldn't be material, I think.

Electrons are material but are not composed. On the other hand, if there were such a thing as the mereological sum of two souls, it wouldn't be material but it would be composed.

Alexander R Pruss said...

Ross Inman pointed out to me that a problem with the definition is that it makes souls be material. After all, souls are often taken to be where the body is, and hence to have limited location.

So, maybe I should talk of *non-derivative* location. The location of a soul derives from that of its associated body.

Drew said...

I think of angels (and souls, both embodied and unembodied) as immaterial, but extended phantasmal entities, and I doubt I am the only one.

What about defining materiality and immateriality based on what the stuff is made out of. If it turns out that particles and energy are both made of the same stuff, maybe strings, then we might be able to define material as composed out of this stuff, and immaterial as not composed of this stuff.

Alexander R Pruss said...

It seems plausible that matter could be of a sort that doesn't occur in our world. Thus, even if in our world matter is stringy, there might be worlds with gunky matter, worlds with indivisible point particles, etc.

I think angels can be manifested in a place, but that's not the same as their being non-derivatively present there.

Cruz Davis said...

Dr. Pruss,

This account of material object would seem to make the property *being material* into an extrinsic property when it seems like we should want our account of materiality to entail that *being material* is an intrinsic property.

For example, if an angel were to gain a limited location in a non-derrivative manner it doesn't seem like we should think that it suddenly becomes a material object.

Perhaps the reply to make here is that the previously described scenario is impossible. But then we would have to provide an account of why it's impossible for the angel to have this property in a non-derrivative sense. In doing this it seems like we would be getting at what the fundamental distinction between materiality and immateriality really is. We should thus reject the account of materiality in terms of limited location due to its failure of getting at the essence of the distinction.

Also, it seems that this account would entail that any subregion of space is a material object, since every subregion of space would have a limited location. This seems like a bad result especially if you aren't friendly to breed of supersubstantivalism that identifies every region with a material object.

Alexander R Pruss said...

Maybe a region of space IS a location, but doesn't HAVE a location?

I don't know how an angel could gain a non-derivative location except by becoming material. :-)

Cruz Davis said...

So if an entity has the exact same size, shape, and stands in all (and maybe only) the same spatial relations of a region then it is exactly located at that region. Since all regions have the same size, shape, etc as themselves then they would be exactly located at themselves. So it seems that regions would have exact locations.

Or we could make a similar argument from the gloss of what a weak location is. If an entity is not free of a region then it is weakly located at that region. No region is free of its sub- or super-regions. So it seems like regions would have weak locations.

I believe it's also relatively common to think that the location relation is reflexive.

So does the angel gain a non-derrivative location BY becoming material? Or does it gain materiality BY becoming non-derrivatively located at a region? Your reply seems to suggest the former. But, it seems that if we hold something like the former it's due to the fact that there is some deeper difference in the distinction between materiality and immateriality, because becoming material appears to be explanatorily prior to possibly having a non-derrivative location.

Alexander R Pruss said...

I like the idea that to be located is to stand in a special relation, being-located-at, to a location. I see no reason to think that the relation that holds between an object and a location needs to hold between the location and itself.

One of my test theories of location in fact directly falsifies the reflexivity of location. On this theory, a location is a subset of an abstract manifold, and the located-at relation is a relation between concreta and abstracta. Locations are abstracta, and do not stand in that relation to themselves.

Another test theory of location is that locations are properties (which properties stand in some relations that make the locations have a topological structure). There is no need to suppose that these properties have themselves.

A further test theory of location is relationalism. Locations, like holes and the like, aren't really part of the ontology then.

Talking of holes, by the way, my definition makes holes material. I guess this is an argument against holes: if there are holes, they are material; but they aren't material; so there aren't any holes.

Cruz Davis said...

Three relatively quick questions:

It seems your account would make shadows material as well. Do you find that to be an uncomfortable result?

Why give up on the more popular accounts of location that are floating around in the literature such as those given by Parsons and Casati and Varzi?

Also I am still curious about your explanation of how an angel could gain a non-derrivative location. It seems that in the way you give the explanation, the angel's becoming material would be explanatorily prior to it's possibly being located. Shouldn't this lead us to think that being material is conceptually or ontologically prior to possibly being non-derrivatively located?

Alexander R Pruss said...

Parsons thinks that there is nothing substantive about the question whether locations are located at themselves. He thinks we could talk either way. I don't see him in that paper committing himself to a particular metaphysics of location. It seems to me that his option of anti-reductionist substantivalism fits very well with the idea that the location relation is not reflexive.

I haven't read Casati and Varzi, but they are officially not trying to give a *metaphysics* of location. So I think their work is consistent with the idea that the fundamental location relation is not reflexive, even though the location relation we talk about is.

If being-non-derivatively-located-at is, say, a fundamental relation, then on the view I've been defending an angel would gain a non-derivative location simply by coming to stand in that relation to some location. :-)

Maybe it's not a fundamental relation, though. Still, the angel would come to have a location in the same way we do, whatever that is.

I am currently rather attracted to a functionalist story about location. A universe has location iff there is instantiated a locational determinable. :-)

The picture of location here is that in a sufficiently regular universe, there will be mathematical laws of nature which will have various variables like m, x, p, etc. The variables correspond to determinables, and their values to determinates of these determinables. The big question, then, is which of the variables correspond to position, and which of them correspond to something else.

Maybe I can say that a determinable is locational iff it is quite natural and has quite natural determinates such that:
(a) these determinates have the right kind of topological or metric structure (I don't know what to require exactly; Hausdorff? locally compact? locally metrizable?); and
(b) the structure of these determinates enters into the laws of nature in a locational way.

What does it mean to say that it enters into the laws of nature in a locational way? Well, first the structure needs to enter the laws of nature. By itself, this doesn't distinguish location from, say, momentum, which has the same metric structure as location.

Second, it needs to enter the laws of nature in a way that resembles the way that it enters into the laws of nature in our world in relevant respects. I like the idea that one relevant respect is that larger differences with respect to this determinable make for a greater difficulty in causal propagation. This distinguishes position from momentum. While it is difficult for particles whose position differs greatly to interact, there is no special difficulty for particles whose momentum differs greatly to interact (otherwise there would not be nearly as many car accidents).

This is very rough, but that's a merit. I suspect that the question whether a given universe has locations is a vague question and in the vague region is non-substantive in Sider's sense. Likewise, the question of which object is material strikes me as vague and non-substantive in the vague region.