xxvi
INTRODUCTION TO VOLUME
3
Einstein's
report
did
not
merely
summarize
or repeat
the works he had
already published
on specific
heats and
quanta.[52]
It
contains
a
number of
new
arguments
and
presents
some
results of the intense
thought
Einstein
had been
devoting
to
these
problems
for
years.
He did
not
confine
his remarks
to
the
topic assigned
to
him,
but used the
opportunity
to
argue
for
his
deeply
held conviction
that
there could
be
no
easy
solution
to
the
current
problems
facing physicists.
Einstein called
upon
the results of the
paper
he
had
pub-
lished in
1910
in collaboration with
Ludwig Hopf
to
justify
his
conclusion:
not
only
was
mechanics
surely
not
generally valid,
but
it
might
well
become
necessary
to
give
up electrodynamics
too.[53]
Both his
report to
the
Solvay Congress
and
his
very
active
participation
in
the discussion of other
reports
show the
depth
and
detail of Einstein's knowl-
edge
of
contemporary experiments on
a
variety
of
subjects
related
directly
or
indirectly
to
quanta.[54]
He
had
questions
and
comments
on
thermal conduc-
tivity,
on
the
explanation
of Felix Ehrenhaft's
"subelectronic"
charges,
on
photoelectricity
and
photochemical
reactions,
on X-ray absorption
and resid-
ual
rays.
His
correspondence
from
this
period provides
further confirmation
of Einstein's involvement with
experiment
and
experimenters
(see
Vol.
5).
Einstein
opened
the discussion after
his
report by commenting
on
the lack
of
a
firm foundation for
developing
the
theory
further.[55]
He had
already
emphasized
that
very
little could
be
taken
for
granted concerning quanta.
One
could
certainly
not
think of
them
as
merely
localized
parcels
of
energy.
In
fact,
as
he
put
it in this
discussion,
"the so-called
quantum
theory
...
is not
a
theory
in
the
ordinary
sense
of the
word,
in
any
case
not
a
theory
which could
now
be
developed
in
a
coherent
way."[56]
Since
neither mechanics
nor
electro-
dynamics
could claim universal
validity any longer,
which
general physical
principles
could
one
count
on
in
trying
to
make further
progress?
Surely,
the
law of
conservation
of
energy was one, although
Einstein had
been
prepared
to
abandon
its
exact
validity
only
the
year
bfore.
He
was
convinced
that
one
could
place
at
least
as
much
trust in
Boltzmann's
principle defining entropy
in
terms
of
probability.
Whatever "weak
glimmer
of theoretical
light"[57]
had
[52]Einstein
1914
(Doc.
26).
[53]Einstein and
Hopf
1910b
(Doc.
8).
[54]See Einstein
1914 (Doc.
26),
Einstein
et
al. 1914 (Doc.
27),
and "Discussion
following
lectures delivered
at
first
Solvay Congress"
(Doc. 25).
[55]Einstein
et al. 1914
(Doc.
27).
[56]"... daß die
sogen.
Quantentheorie
...
keine Theorie im
gewöhnlichen
Sinne des
Wortes,
jedenfalls
keine
Theorie,
die
gegenwärtig
in
zusammenhängender
Form entwickelt werden
könnte." Einstein
et al. 1914
(Doc. 27),
p.
353.
[57]"schwache
Schimmer theoretischen Lichtes." Einstein
et
al. 1914 (Doc.
27),
p.
353.