Re: CAUSALITY IN PHYSICS (was drag force)

[Leigh Palmer <palmer@SFU.CA>]

> In Philosophy 1, I learned there is no cause and effect only temporal
> propinquity.

Philosophers are exempt from the constraint of congruence with Nature.

Given the relation F = ma, one must recognize that the relation applies to
a physical model in which a particle undergoes acceleration simultaneously
with the application of a force.

Question: is force the causal agent to which the effect of acceleration
can be attributed?

Answer: we have not enough information to make that determination. The
philosopher quoted above is perfectly correct in this case.

Hold on - isn't this a simple case? Yes, it is. It is *too* simple. By
hypothesis this equation applies strictly to a model. The model closely
resembles the phenomenon of a a physical body moving under the influence
of an applied force. It is in the details which distinguish the model
from the physical system that the causal relation between force and
acceleration is to be found. The gradual buildup of the force over a very
short time after its initial application and the slight compression of
the body over this same time interval will corroborate the causal
relation we naturally assign. In light of what is really happening the
metaphysical questions are readily seen to be trivial.

The philosophical statement is about models; causality may not apply to
models which are insufficiently physical. The very word "simultaneously"
should set off alarm bells in the mind of any modern physicist.

Leigh