28 April 2008

marginally physical objects

or, contemporary myths in physicalism

dare i suggest that there is a vagueness in what, exactly, is implied in the concept or ontological category of the "physical". our everyday definition of a physical object is something that you can bump your head against. yet it seems that even the most innocent of everyday, physical things are pseudophysical in that they are also at least in some bit abstract. also, some processes of these physical objects get lumped into the physicalist account. does this move the discussion from physical objects to.. well something else?

all in all, there are some specific cases i have in mind...where the vagueness of the category is painfully apparent. here are three scientific examples.

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1. fields - our best physics posits the existence of fields, not only as necessary objects in the universe (as, say, scientists might posit numbers and theories) but also as strictly physical objects. handydandy wikipedia says that a field is 'the presence of a physical quantity at every point in spacetime.' hm.. something should ring a bell already as the definition seemed a bit off. the field clearly isn't made up of whatever the most minute particle might be, just as i am or stars are. no, fields seem to be not physical objects themselves but the position, behavior, and propensity for specific physical objects as they pass along specific regions of spacetime. does this add up to a physical object? well no, it's not a physical object and it isn't even made up OF physical objects. so, if even in our most sacred science there are objects that are straddling the line ontologically, what can we expect in other fields?

2. mental states - no doubt our brains have a lot to do with our mental states. so much so, of course, that when our brain ceases to function correctly our mental states cease to function accordingly, ad empirically demonstrated in brain damage studies. but, as some people have asked before me i'm sure, are brain states the same as mental states? is there an identity relationship be tween these two characterizations of whatever it is that's going on inside my head? I think kripke's argument is very powerful... take a look at it and see for yourself.

N= necessarily
P = possibly

(a) N (heat = molecular motion).

this is a necessary a posteriori truth. is it possible to have heat without molecular motion? well no. no matter what, if it's heat, it's caused by molecular motion. sure, there might be sensations of heat without molecular motion. but if it's real heat, it's real molecular motion. now, can we say

(b) ? N (pain = c-fibers firing)

well let's put the identity to the test just like last time. is it possible to have the sensation of pain without it being pain? well it seems like the answer is pretty obvious, NO! if you feel pain you have pain! this calls into question whether c-fibres firing just IS pain. once again, this either means that definition of pain provided by the best anatomical science is incomplete (and it doesn't seem to be, at least here on earth), or that pain just is not the same as c-fibers firing, leaving us with

(c) ~N(pain = c-fibers firing)

rounding out the discussion on physical objects, and brain states, where does this leave us? well it leaves us in a more primitively intuitive position where we think that the brain and its states (physical objects) sure do have a lot to do with our minds (presumably other than physical objects) yet they aren't the same thing. so things like belief, pain, fear, etc are partially physical.

3. species - reading fodor's critique of natural selection has got me thinking a lot about philosophy of biology lately. one of things i've come to believe is that talk of species and groups of animals with similar properties and so forth isn't strictly speaking physical. of course, this comes of no surprise to anyone who's familiar with set theory or even mereology. anyway, the abstractions we can assign to the physical characteristics of individual animals across similar-enough genetic liniage definitely makes the concept of 'species' an ontologically dualist one.
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well then, what do these suggestions do, if anything? i think it does two things. first, it reinforces the insight mcginn had in saying that ontological categories are oftentimes ill-defined. in these three cases i have given examples with a focus on the vagueness of the 'physical' category, but in doing so i've also muddled up 'abstract' and 'mental'.

a further, more powerful consequence of establishing these marginally physical objects is the clear rejection of ontological physicalism. If there is someone who wholds that what there is is physical and that's all there is, yet what's physical can't be said to be always physical, then physicalism is false.

1 comment:

Der Jasager said...

on #1:
mathematically speaking, a field comprises a set of numbers at each point in space--i think that is what the wikipedia definition is alluding to. how these numbers (and thus the field) are interpreted is another matter.

to some degree, we and the stars are fields ("matter" probability fields) that are localized in the sense that there is a VERY low probability associated with us being outside a VERY local region in space.

your discussion seems to have the bias of viewing things without mass as not being physical. e.g. the electromagnetic field which has no mass but has influence on particles with mass. yet fields (and particles) have energy, so perhaps instead of viewing things with mass as physical objects, and things that influence massed objects as "straddling" somehow, it would more accurate from a physics perspective to view energy as the determining factor for the physicality of things.