DOC. 42
SPECIAL AND GENERAL RELATIVITY
323
TWENTY-ONE
In
What
Respects
Are the
Foundations
of
Classical
Mechanics
and
of the
Special
Theory
of
Relativity
Unsatisfactory?
We
have
already
stated several times
that
classical
mechanics
starts out
from
the
following
law:
Mate-
rial
particles sufficiently
far
removed
from
other
ma-
terial
particles
continue
to
move
uniformly
in
a
straight
line
or
continue
in
a
state
of
rest.
We have
also
repeatedly empha-
sised that this fundamental
law
can
only
be
valid for
bodies of
reference
K
which
possess
certain
unique states
of
motion,
[38]
and which
are
in
uniform translational motion relative
to
each
other. Relative
to
other reference-bodies
K
the
law
is not
[39]
valid.
Both
in classical
mechanics and
in
the
special
theory
of
relativity
we
therefore differentiate between reference-bodies
K
relative
to
which the
recognised
"laws of
nature"
can
be
said
to
hold,
and
reference-bodies
K
relative
to
which
these
[40]
laws
do
not
hold.
But
no
person
whose mode of
thought
is
logical can
rest
satisfied with this condition of
things.
He
asks:
"How does it
come
that certain reference-bodies
(or
their
states
of
motion)
are
given priority
over
other reference-bodies
(or
their
states
80