Teuton wrote:

jamest wrote:

Teuton wrote:
I think it's doubtful whether it's possible for particles to be literally zero-dimensional.

Fundamental particles - indivisible entities - would have to be, I think, since there cannot be separate points/parts of existence within indivisibility.

"Elementary particles in the ordinary view of things are point particles. A point can’t have many, many properties. A point is too simple to have properties. However, we know that elementary particles have a lot of properties. They have spin, they have electric charge, they have something called isotopic spin, they have a quantum number called color - it’s not got anything to do with ordinary color - they have generations that they belong to, there are whole catalogs of different kinds of quantum numbers, of different kinds of properties that quarks, electrons, netrinos, or photons have. It sounds unreasonable for a point to have that structure. So the feeling most of us have is that, at some level, if you look deeply enough into things, you‘ll discover that particles aren’t points. That they must have all kinds of internal machinery that gives them these properties."

(Leonard Susskind: http://felinequanta.blogspot.com/2009/0 ... skind.html)

Oh, I wouldn't argue that particles don't display having many properties/attributes, but we must remember that the reality of these particles, beyond the perception/conception/experience of them, is debatable.
... So, you cannot counter my logic regarding the indivisibility of particles merely from what is observed from/of them. That is, observation is not the seat of metaphysical/ontological verification... which is what your response implies.

Teuton wrote:

jamest wrote:
Well, my problem is with those that define 'natural' in terms of physical existence alone.

There are naturalistic property dualists who think that mental properties are nonphysical but perfectly natural properties.

Are you one of them?

My opinion is that different realms of existence cannot coexist/interact. In fact, Descartes' dualism took one hell of a battering - for good reason. If needs be, I'll explain why.

Jef wrote:

Teuton wrote:

Jef wrote:The point particles of certain quantum theories are definitively physical objects despite of their lack of extension.

Literally 0-dimensional point particles are not real physical objects but idealized theoretical objects.

Quite true. Particles are idealized that way because there is no experimental evidence of them having spatial extension, though you are almost certainly correct that they, in fact, do.

Isn't anything that physically exists at least one Planck unit?

shh wrote:

Jef wrote:
Isn't anything that physically exists at least one Planck unit?

Not really. For example the Planck unit of mass is 2.2x10-8 kg, which is macroscopic and more massive than a small grain of sand.

shh wrote:

Jef wrote:

Teuton wrote:

Jef wrote:The point particles of certain quantum theories are definitively physical objects despite of their lack of extension.

Literally 0-dimensional point particles are not real physical objects but idealized theoretical objects.

Quite true. Particles are idealized that way because there is no experimental evidence of them having spatial extension, though you are almost certainly correct that they, in fact, do.

Isn't anything that physically exists at least one Planck unit?

That's an interesting question. Why? Because the value of anything that is ordained as the smallest measure, cannot itself be of any measure. Why? Because, let us say for example (and argument's sake), that the smallest unit of measure was 1cm. The question then begs: how do you know that 1cm is bigger than 0cm? That is, how/why is 1cm greater than something of zero length?
You simply cannot differentiate between 1cm and 0cm if there is no distance less than 1cm. They both mean the same thing.

The essential point is that length itself has no meaning [in reality] unless it is both infinite and infinitessimal. That is, any theory advocating a limit to the smallest finite length, must be illogical... and therefore, erroneous.

Teuton wrote:If 0-, 1-,and 2-dimensional objects (points, lines, surfaces) are accepted as idealized theoretical objects of physics but not as real physical objects, then we can use the following traditional definition (going back to Descartes):
x is a material/physical object =def x is a 3D object
And those who think that physical objects are also temporally extended can use this definition:
x is a material/physical object =def x is a 4D object
Footnote: Fields and space/spacetime itself can count as 3D/4D objects.

On the other hand, if space has more than three dimensions, then spacetime is not a 4D object but, say (as in string theory), an 11D object. So perhaps we should say that a physical object is an object with at least three spatial dimensions.

jamest wrote:
Oh, I wouldn't argue that particles don't display having many properties/attributes, but we must remember that the reality of these particles, beyond the perception/conception/experience of them, is debatable.
... So, you cannot counter my logic regarding the indivisibility of particles merely from what is observed from/of them. That is, observation is not the seat of metaphysical/ontological verification... which is what your response implies.

The argument that intrinsic physical properties must be grounded or rooted in the internal structure of their bearers, and that 0-dimensional and thus internally structureless objects are too simple to be bearers or substrates of intrinsic physical properties is indeed a metaphysical one.

jamest wrote:

Teuton wrote:
There are naturalistic property dualists who think that mental properties are nonphysical but perfectly natural properties.

Are you one of them?

No.

jamest wrote:
My opinion is that different realms of existence cannot coexist/interact. In fact, Descartes' dualism took one hell of a battering - for good reason. If needs be, I'll explain why.

Cartesian substance dualism entails property/attribute dualism, but property/attribute dualism doesn't entail Cartesian substance dualism. In fact, all anti-Cartesian property dualists maintain that all substances are physical ones. The only thing they deny is that all physical substances have only physical properties.

"The dualism implied here is instead a kind of property dualism: conscious experience involves properties of an individual that are not entailed by the physical properties of that individual, although they may depend lawfully on those properties. Consciousness is a feature of the world over and above the physical features of the world. This is not to say it is a separate 'substance'; the issue of what it would take to constitute a dualism of substances seems quite unclear to me. All we know is that there are properties of individuals in this world—the phenomenal properties—that are ontologically independent of physical properties."

(Chalmers, David J. The Conscious Mind: In Search of a Fundamental Theory. New York: Oxford University Press, 1996. p. 125)

Teuton wrote:
To find a satisfying definition of "physical property" is more difficult, because the following is insufficient:
X is a physical property =def X is a property of physical objects

Actually, what the best, most adequate definition of "physical property" is is sort of a $1000000 question.
Good luck, guys!

P.S.:
For your information: Many philosophers and especially many physicalists favour one of these two definitions:

1. X is a physical property if and only if X is expressed by a predicate of a theory in physics or, broader, in the physical sciences that is true at the actual world.

2. X is a physical property if and only if X is expressed by a predicate of a theory in physics or, broader, in the physical sciences that is true at some possible world or other (i.e. not necessarily at the actual world).

These definitions may seem attractive, but they are known to be problematic!