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Re: Cause and Effect



At 03:09 PM 10/23/00 +0530, D.V.N.Sarma wrote:
No doubt force can be measured but it also can be felt.
Acceleration cannot be felt, it can only be measured.
...
Force concept is
definitely more subjective and intuitively understood than
acceleration. I do not think there can be any two opinions about
this because this is a matter of experience of all of us.

1) There are at least two opinions. My opinion differs from Sarma's.

If I observe an eccentric lump on a rotating wheel, I can tell from across
the room that it is undergoing acceleration. This is 100% intuitive. No
perception of force could be more intuitive than that.

2) I generally take "subjectiveness" to be a bad thing in the physics
lab. I thought the whole purpose of physics training was to teach people
the advantages of objective measurements and objective thought processes.

Apparently Sarma uses "subjective" as a term of praise. I did not realize
that until just now. This caused me to misunderstand the fine points of
his earlier note.

I consider "intuition" to be a two-edged sword. It is basically a fancy
word for "guessing". An accurate intuition is a great help, but an
inaccurate intuition is worse than nothing. Just because something is
intuitive doesn't mean it is right. It's intuitive that the world is flat
and stationary at the center of the universe.

Kip Thorne is fond of saying "education is the process of cultivating your
intuition".

Acceleration by all accounts is a derived quantity L/T*2.

Force by all accounts is a derived quantity M*L/T^2. So what?

What does "derived quantity" have to do with cause-and-effect
relationships? I've never seen cause-and-effect relationships derived by
dimensional analysis!

As a matter of fact I have once posted a letter to this list
saying that motion (not acceleration) is more fundamental than
time. Because without motion there is no time. When
nothing happens, there are no events and there is no time.

Even if true, this is vaporous speculation with no measurable
consequences. Why not say by the same token that without motion there is
no distance? The properties of an imaginary universe without motion,
without time, and presumably without distance are not interesting to me,
and prove nothing about cause-and-effect relationships in the real universe.