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Re: Causation in Physics: F=ma



For the record, I did not say that because
the reference implies that forces are causes
that forces are causes. I simply stated that
the reference implied that forces are causes.
The reference did not explicitly state that
forces are causes, so I added that observation.

I do not accept John's assumption that a cause
must precede its effect. I'm still waiting for
someone to provide evidence that the word
"cause" necessarily implies precedence.

Daniel Crowe
Oklahoma School of Science and Mathematics
Ardmore Regional Center
dcrowe@sotc.org


-----Original Message-----
From: John S. Denker [mailto:jsd@AV8N.COM]
Sent: Friday, November 14, 2003 3:45 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Causation in Physics: F=ma


On 11/14/2003 04:05 PM, Dan Crowe wrote:
The key phrase in the quote provided by Larry is
"the effects of forces on the motion of objects."
"Effects" implies that forces cause changes in motion.

The phrase was not "the relationship between forces
and changes in the motion of objects."

Oh, great. Now we have 9 textbooks and the National
Academy offered as "evidence" that F causes ma and
not vice versa.

What's next? Are we going to agree that insects
have four legs, because it says so in Leviticus?

This "evidence" isn't evidence at all. This sort
of argument is called "appeal to authority" and
it is completely improper. Science is based on
observations and logic, not on appeal to authority.
http://www.av8n.com/physics/authority.htm

I really don't care if Isaac ben-Abraham, Isaac
Newton, and Isaac Asimov all say that F causes ma
and not vice versa. It's still not true.

I repeat one of the standard elementary counterexamples:
I have a particle of mass (m) in a centrifuge.
Everything in the centrifuge is subject to an
acceleration (a), perhaps 10,000 Gees. I can calculate
the force on the particle according to the formula F=ma.
Do you really expect anybody to believe that the force
causes the acceleration? I know the acceleration even
in cases where I don't know the force (perhaps because
I don't know the mass). The acceleration is the same
even if there is no particle at all!

I've started debunking textbooks when I was six or
seven years old. I see no reason to stop now.