DOC.
56
359
we are
determining
the
above
electromagnetic
effects
from
the
motions and
configurations
that take
place
after the instant
t.
In the
first
case
the electric field is calculated
from
the
totality
of
the
processes
producing
it,
and
in the
second
case
from
the
totality
of
the
processes
absorbing
it. If the
whole
process
occurs
in
a
(finite)
space
bounded
on
all sides, then it
can
be
represented in the
form
f
=
f1
as
well
as
in the
form
f
=
f2
.
If
we
consider
a
field that is emitted
from
the finite into the infinite,
we
can,
naturally,
use
only
the
form
f
=
f1
,
precisely
because the
totality
of
the
absorbing
processes
is
not taken into
consideration.
But
here
we are
dealing
with
a
misleading
paradox of
the
infinite.
Both
kinds of representation
can
always
be
used,
regardless of
how
distant the
absorbing
bodies
are
imagined
to
be.
Thus,
one
cannot
conclude
that the solution
f
=
f1
is
more
special than the solution
a1f1
+
a2f2,
where
a1 +
a2
=
1.
That
a
body
does
not
"receive
energy
from
infinity
unless
another
body
loses
a
corresponding
quantity of
energy" cannot
be
brought
up
as an
argument [6]
either, in
my
opinion.
First
of
all, if
we
want
to
stick
to
experience,
we
cannot speak
of infinity
but
only
of
spaces
lying
outside the
space
consid-
ered. Furthermore,
it
is
no more
permissible
to
infer irreversibility
of
the
electromagnetic elementary processes
from
the
nonobservability
of
such
a
process
than it is permissible
to
infer irreversibility
of
the
elementary
processes
of atomic
motion from
the
second
law
of
thermodynamics.
[7]
2.
Jeans' interpretation
can
be
disputed
on
the
grounds
that it
might
not be permissible to
apply
the
general
results of statistical
mechanics to
cavities
filled with
radiation.
However,
the
law
deduced
by
Jeans
can
also
be
[8]
arrived
at
in the
following
way1.
1Cf.
A.
Einstein,
Ann.
d.
Phys.
17 (1905): 133-136.
[9]