Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: CAUSATION IN PHYSICS



At 02:55 PM 10/14/00 -0500, John M. Clement wrote:
This could be a limitation imposed by language which has constructs for
causality, and also for unrelatedness, but does not have a good construct
for correlated things which are not causally related in time.

That's an interesting hypothesis, but it doesn't fit the facts. In this
case, our language has perfectly good constructs to describe the
relationship between F and ma. The relationship is called "equality" or
"equivalence".

To accelerate a block you must push it.

Not strictly true.
-- you might pull it instead of pushing it
-- in the ordinary (gravitating) lab frame, all you need to
do is let go of the block and it will accelerate toward the floor.

To push a block you must accelerate it.

Also not strictly true.
-- It might not accelerate because of some force that opposes your push.

The right-hand side of ma=F must be the _total_ force.

To accelerate a block you must push it.
The latter construction does not make sense.

Neither of the two contrasted constructions made perfect sense, but the
lack of sense was comparable in both cases, and was due to imprecise
statements about the mechanics, not due to anything related to causation
(the topic of this thread).

Do we really know that acceleration and Force are "exactly" simultaneous?

There is every reason to believe they are simultaneous, and no reason to
believe otherwise. If anybody has theoretical or experimental evidence to
the contrary, please let us know.

So the fact that mathematically there is not way to separate cause and
effect, does not in any way alter the fact that humans tend to think of
forces as causes and acceleration as an effect.

The fact that humans tend to think X, Y, or Z provides rather weak evidence
as to the truth of X, Y, or Z -- especially when the humans are asked
technical questions about force, acceleration, and causation before knowing
much about force or acceleration, and before having anything approaching a
workable definition of causation.