Re: CAUSATION IN PHYSICS

[Ludwik Kowalski <KowalskiL@MAIL.MONTCLAIR.EDU>]

John Denker wrote:

> I hope most people on this list, if they thought about it for a moment,
> would agree with the observation that "equality" is symmetric while
> "causation" is nonsymmetric.

No great mental effort was needed to agree with the above. John is
referring to idealizations in which F acts on a particle, or on a rigid
body. Leigh, on the other hand, was bringing a very persuasive
argument for "F being a cause of a" in non-ideal situations. The
center of mass of a real body does not start accelerating at the
same moment at which the force is applied. What do you think
about this argument, John? In the last message Leigh wrote:

> F = ma is a model which describes the interaction of a force with a
> particle, a point mass. You guys are reifying again! Real forces do
> cause accelerations. If you've got any mathematically pristine point
> masses around to use to check then you may have a problem
> determining the causal relation between force and acceleration - if
> you succeed in coupling your force to the particle! For extended
> objects forces manifestly cause accelerations.