DOC.
60
379
Doc.
60
ON
THE DEVELOPMENT
OF
OUR
VIEWS CONCERNING THE NATURE
AND
CONSTITUTION
OF
RADIATION
by A.
Einstein
[Deutsche
Physikalische
Gesellschaft,
Verhandlungen 7
(1909): 482-500.
Also
in
Physikalische
Zeitschrift
10
(1909):
817-826]
(Presented at
the session of the Division
of Physics
of the 81st
Meeting
of
German
Scientists
and
Physicians
in
Salzburg
on
September 21,
1909.)
[1]
(Cf.
above
p.
417)
Once
it
had been recognized
that light exhibits
the
phenomena
of
inter-
ference
and
diffraction, it
seemed
hardly
doubtful
any longer
that light is
to
be
conceived
as a
wave
motion.
Since light
can
also
propagate through
vacuum,
one
had
to
imagine
that
vacuum,
too,
contains
some
special kind
of matter
that
mediates the
propagation
of light
waves.
For
the
interpretation
of
the
laws
of
the
propagation
of
light
in
ponderable
bodies, it
was necessary
to
assume
that this
matter, which
was
called luminiferous
ether,
is
present in
them too,
and
that in the interior
of ponderable
bodies
as
well, it
is
essentially
the
luminiferous ether that mediates the
propagation
of
light.
The
existence
of
this luminiferous ether
seemed beyond
doubt.
The
first
volume of
the
excel-
lent textbook
by
Chwolson,
which
was
published
in
1902,
contains in
the
Introduction the
following sentence
about the ether:
"The
probability
of the
hypothesis
on
the existence of this
agent
borders
extraordinarily closely
on
certainty."
[2]
However, today
we
must regard
the
ether
hypothesis
as an
obsolete stand-
point.
It
is
even
undeniable that there is
an
extensive
group
of
facts
concerning
radiation that
shows
that light
possesses
certain fundamental
properties
that
can
be
understood far
more
readily from
the
standpoint
of
Newton's
emission
theory
of light than
from
the
standpoint
of
the
wave
theory. [3]
It is therefore
my
opinion
that the
next stage
in the
development
of theore-
tical
physics
will
bring
us a
theory
of light that
can
be
understood
as a
kind
of fusion of the
wave
and
emission theories
of
light.
To
give
reasons
for
this
opinion and to
show
that
a
profound
change
in
our
views
on
the
nature
and
constitution of light is
imperative
is the
purpose
of
the
following
remarks.