the mass "mechanism" (repost)
MARK ADKINS
[Someone told me this never appeared.]
In a previous article, ste...@sel.hep.upenn.edu (Kevin Sterner) says:
>Using only space and time, you can take a standard test object--say, a
>marble--and see how it orbits around or falls towards various bodies.
>If you accept space and time as having physical significance, you can't
>handwave-away changes in the relative distance and velocity between
>two bodies. You can easily deduce that the attraction between the
>marble and the attractive bodies depends upon some property of the
>attractive bodies. The motion of the marble is objectively different
>for different attractive bodies, so that property objectively exists.
You can easily deduce that, but it isn't logically necessary. In fact,
I believe that Hamiltonian dynamics does away with vector quantities
(like force, acceleration, velocity, etc.) altogether and makes due
with quantities like energy and action. It seems to describe the
behavior of a frictionless system of bodies with the same mathematical
precision as Newtonian dynamics.
>Alternatively, you can use a spring to push two test objects apart.
>The speed at which they are pushed apart depends upon some property
>of the objects. This property also objectively exists.
At the risk of handwaving and other rude gestures, let's stop to consider
the concept of mass within the context of Newton's philosophical
framework (i.e., using "forces," "masses," and "accelerations").
All of these entities are defined tautologically, in terms of one
another. We can't even begin to define mass, then, without defining
it in terms of force and acceleration (hence velocity), both of which
are relational properties applicable to systems of objects, not intrinsic
properties of individual objects.
If we really want to enter the handwaving danger-area of falling
rocks, I challenge anyone to provide a definition of "an object"
which isn't arbitrary, subjective, and imposed by conscious beings.
There is no such thing as an isolated object, if one is to define
objects in terms of the relational properties of forces. There is
a gravitational pull on the Earth from every other material object
in the universe, as well as other force interactions such as
electric and magnetic fields. In order to define the Earth as
an object, we have to define this concept of objecthood by
arbitrary edict at some level of force attenuation or some distance
of intervening space. The Earth is made of particles, and these
particles are separated by intervening spaces and exert forces
on one another: the Moon is separated from the Earth by an intervening
space and both bodies exert forces upon one another; but the Moon is not
part of the Earth because our brains and bodies evolved under
circumstances in which we use using considerably smaller scales of
spatial separation and considerably stronger magnitudes of force for us
to consider "objects" to be "separated" or "connected" with one another.
A pair of magnets we have to pry apart may be treated as a single object,
but this same pair of magnets, sitting across the room from one another,
is never considered to be a single object, despite the weak magnetic
force of attraction between them.
Then there is the problem that the intervening "space" isn't. It
isn't space. Every point of "space" has a non-zero value for some
field of force, and "space" is teaming with virtual particles.
Beyond this, it isn't clear to me why it is objective to consider
intervening space as a separate entity. Why is space not part of the
objects, and why are the "objects" and "space" objectively delineable
at all?
It seems to me that our perceptual and analytic modes -- our conscious
minds, to put it more bluntly -- require us to impose all kinds of
separations and connections which would not, in the absence of such
minds, have any objective reality. Our science thus depends upon
our selective attention and upon logical connections which transcend
the physical. We conceive of the individuality of events and objects,
and the relations between them, only by excluding other objects and
events according to the subjective standards which seem, to us,
perfectly obvious if not inescapably necessary. While there may
be no other way to conduct science, or indeed our daily affairs,
it can to a greater or lesser degree sometimes be beneficial, even
in the formulation and evaluation of scientific models, to remember
these things.
--
"Love -- it's not just a good idea: it's the law." -- Aleister Crowley
Mark Adkins (eme...@aztec.asu.edu)