[hist-analytic] Materialism and mass as a unit of measurement

Baynesr at comcast.net Baynesr at comcast.net
Fri Jan 28 16:19:10 EST 2011


"...physicalism...concerns the ontology of the world. It claims that the content of the world is wholly exhausted by matter. Material things are all the things there are." (Kim [2005] 150) 

Now consider an argument proposed by Block and Stalnaker as described by Kim. 


Neurophysiology 
Neural State N1 causes neural state N2 
Pain = N1 
Sense of distress = N2 
Therefore, pain causes a sense of distress. 

Note the identities. They play no real role in the explanation on Kim's account. He remarks: 

"True, these identities do have a role in the derivation of 'Pain causes distres,' but this is not an explanatory derivation; rather, it is a dervivation in which 'equals for equals'." (Kim [2005] p. 146. Elsewhere, and repeatedly, he describes identities as "rewrite rules." But is this correct? Suppose it is. If so, the Block-Stalnaker case of explanation appears to fall short. Suppose on Block-Stalnaker all that exists is matter, although we could reconstruct the argument I will propose as directed agains Kim, alone. 

Kim is, definitely, committed to two things. First, that matter and matter alone exists; and second, matter provides the subvenient basis for supervenience. Physicalists like to get technical with dualists, particularly when "peddling" their physicalism. Let's see how literal their "materialism" actually is. 

We are told that only matter exists. Well, what about a beam of light? It has no mass, and so we might want to say that it is not physical. Is this right? More importantly is the sense in which it is right consistent with Block-Stalnaker on the role of identity statements? I think not. Suppose we begin by saying 

1. A photon is massless 

This is a given of physics. Another given of physics is the momentum of a photon can be expressed this way, where 'P' is momentum: 

2. P = E/C (where 'C' is the speed of light; and 'E' is (rest) energy) 

Now we, also, have it as a given that 

3. E = MC^2 (Yippee!) And so, from (2) and (3) we get 

4. P = MC^2/C 

Leaving us with 

5. P = MC 

But wait! Doesn't (5) contradict (1), since 'M' means 'mass'? David Susskind once raised the question whether the "units" associated with the momentum of a photon are the same as those for massed particles 

6. P = MV (for picky people assume we are dealing with vector properties where applicable). 

That is: does 'M' in both (5) and (6) get indicated by the same units of measure? He sees no problem. I do, one brought on by accepting Block-Stalnaker. If we suppose that these identities are "rewrite rules" then there is no force to the claim that the identity is ontological; it becomes a matter of choice of convention. But if this is so, then neither Block-Stalnaker nor Kim's materialism can be sustained as a ontological claim, particularly in the case of things like photons. By the way, Kim has not committed to "ontological relativity." The photon is interesting in another way relevant to discussions of physicalism. 

I am concerned with Kim's belief that subvenient bases of supervient properties must be material. Here we have a massless oscillatory field phenomenon consisting of two waves wedded in geometrical symmetry: the magnetic wave at a 90 degree angle to the electric. Now these two are not identical. First, either the magnetic or the electrical properties of the beam of light satisfies being the subvenient basis of the other; so we appear to have mutual supervenience in the absence of a material subvenient base. I would add, as an interesting aside, that we have here a symmetry dependent periodicity which will become significant as I examine issues raised by Mele's discussion and dualism generally. 

The main point: we cannot use Block-Stalnaker identities in explanation since they allow idntifying a photon as possessing mass. Once we isolate the sense in which this IS allowed we forfeit the idea that explanation can be transferred from talk of one thing, such as c-fibers to another, pain. 

I haven't edited this darn thing. I may revise it as I usually do pending a reread at some point. 

Steven Bayne 







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