From: ramsay@unixg.ubc.ca (Keith Ramsay)
Subject: Re: invention of time
Organization: University of British Columbia, Vancouver, B.C., Canada
Date: Tue, 8 Sep 1992 01:02:43 GMT

In article <snodgras.715630298@crash> snodgras@crash.cts.com 
(John Snodgrass) writes:
>      Time dilation is assigning geometrical cause to physical events.
>The question arises, is it possible to rule out physical
>causes for the phenomena attributed to time dilation?

Thank you for putting your objection in concise terms here.

First, as an aside, why do you assume that geometry is not "physical"?

Second, you seem to be grossly overinterpreting the word "cause",
which is often used in a very informal way.  Imagine that one is
having a candlelight dinner, and nods off. One then wakes up some time
later, unaware that it has been several hours since one fell asleep.
One asks, "Why are the candles so much shorter than they were?" The
answer "Because of the passage of several hours' time" is not
attributing some novel cause to the shortening of the candles; it is
just singling out the important feature of the (known) process (of
burning) which you needed to know. It will also explain, for example,
the "cause" of the clock on the wall registering a later time.

Likewise, relativity ascribes physical causes to the effects it
described, just as much as any other theory does. Clocks function as
always supposed, by an interaction of mechanical and other physical
effects. A clock ticks in the way it does because of the forces
involved, not because of some extra entity "time" causing it to do so.
It would, perhaps, be good if accounts of relativity were to make this
point somewhat more clear.

You can say, if you like, that the clocks run more slowly when moving
quickly "because of" some details of the interactions of the
mechanism, and how it operates when moving at relativistic speed. In
some sense, this account will be a more faithful use of the word
"cause".

The details of its mechanism are not especially relevant to an
exposition of relativity, however, since the same correspondence
between the activity of stationary and moving bodies is supposed to
hold for any other kind of system, even if it doesn't operate by
springwork.

The crucial fact, from a modern point of view, is the kinds of
symmetries which (all known) phenomena of nature are found to have.
The Lorenz transformations, the symmetries of special relativity,
transform a model of a ticking clock into a model of a more slowly
ticking clock, moving at high speed. If the theory is correct, then
all the (physical!) forces causing a clock to tick, whatever they may
be, are symmetric under that transformation. If one description is an
accurate description of the behavior of a clock, the other is expected
to be as well. The forces should therefore, if the clock is caused to
move at great speed, cause it to tick less frequently.  Likewise,
fast-moving particles will decay, *for whatever physical cause of
their decay*, with a longer mean time (with respect to Earth clocks)
if they are moving quickly (with respect to the Earth).

To state that time runs more slowly at high speeds is just a summary
of this generalization, not a substitution of an extra causal factor.

Keith Ramsay
ramsay@unixg.ubc.ca
Newsgroups: sci.philosophy.tech