Re: [Phys-l] F causes a

["Richard Tarara" <rbtarara@sprynet.com>]

> [Original Message]
> From: Hugh Haskell <hhaskell@mindspring.com>

> I don't know the answer to this question, but I am willing to 
> entertain the possibility of changing the notation for NSL to make a 
> causal connection explicit. I don't know if that would solve the 
> issue or not, but it would satisfy our very human desire to see 
> causal connections in nature. If it happens that there is no 
> experiment that could establish the truth of a causal connection one 
> way or the other, then I see no harm in making an arbitrary choice, 
> as long as we are explicit about the fact.
>
> Hugh
> -- 
I don't have an experiment, and being 40 years away from Jackson's E&M
certainly doesn't help my thinking, but I seem to recall some time
dependent equations that _might_ have some relevance.  Since information
about changes in the electric and magnetic fields propogate at a finite
speed (c), and because all the macroscopic pushes and pulls that we talk
about in Newtonian Mechanics are ultimately E&M interactions, might there
not be the time delay that Hugh is looking for?  For length scales of
centimeters or even millimeters we are probably talking pico-second or
shorter delays (that I have no idea how to measure). 

On a more practical level, I'm with Jim Green.  I think most people,
certainly most students and probably most of us, would think about the 2nd
law in operational terms.  If I want an acceleration--I know I  need to
produce a force.  If I want a force, I don't think about producing an
acceleration.  That may not be formally or mathematically true cause and
effect, but as a practical matter it is.

JD doesn't see how 'compelled' or 'forced' can be interpreted as 'causing'.
I don't really see how to NOT interpret those words as causation.  Again,
that doesn't mean Newton is right if he meant 'causes', but from either
translation, that is what I would infer he meant.

Rick