DOC.
56
361
compatible
with
the
facts.
Why,
after all,
do
solids emit
visible light
only
above
a
fixed, rather
sharply
defined
temperature?
Why
are
ultraviolet
rays
not
swarming
everywhere
if
they
are
indeed
constantly
being
produced
at
ordinary temperatures?
How
is
it
possible
to store highly
sensitive
photographic
plates
in cassettes
for
a
long
time
if
they
constantly
produce
short-wave
rays?
For
further
arguments
I refer
to
§166
of
Planck's
repeatedly
[15]
cited
work.
Thus,
we
will
indeed have to
say
that
experience
forces
us
to [16]
reject either
equation
(I),
required
by
the
electromagnetic
theory,
or
equation
(II),
required
by
statistical
mechanics,
or
both equations.
4.
We
must
now
ask ourselves
how
Planck's radiation
theory
relates
to
the theory
which
is indicated under
2., and which
is based
on our
currently
accepted
theoretical foundations. In
my
opinion
the
answer
to
this
question
is
made
harder
by
the fact that Planck's presentation of his
own
theory
suffers
from
a
certain
logical
imperfection.
I
will
now
try to
explain
this
briefly.
a)
If
one
adopts
the
standpoint
that the
irreversibility
of the
processes
in
nature
is
only
apparent,
and
that the irreversible
process
consists in
a
transition
to
a more
probable state,
then
one
must
first
give
a
definition
of
the
probability
W
of
a
state.
The only
definition
worthy
of
consideration, in
my
opinion, would
be
the
following. [17]
Let
A1,A2...Al
be
all
the
states
a
closed
system
at
a
certain
energy
content
can
assume, or,
more
accurately, all the
states
that
we
can
distin-
guish
in
such
a
system
with the
help
of certain
auxiliary
means. According
to
[18]
the classical
theory,
after
a
certain time the
system
will
assume one
particu-
lar
state
(e.g.,
Al)
and
then
remain
in this
state
(thermodynamic
equilib-
rium). However, according to
the statistical
theory
the
system
will
keep
assuming,
in
an
irregular
sequence,
all these
states
A1...Al.1 If the
system
is observed
over
a
very
long
time
period 6,
there will
be
a
certain
portion
tv of
this
time
such
that
during
Tv,
and
during
Tv
only,
the
system
occupies
the
state
Av.
[The
quantity]
tv/9
will
have
a
definite
limiting
[20]
value,
which
we
call
the probability
W
of
the
state
Av
under considera-
tion.
1That only
this last interpretation is tenable follows
immediately
from the
properties
of
Brownian
motion.
[19]