xxviii
INTRODUCTION
TO VOLUME
2
impressed by
the
successes
of
classical mechanics and
of Maxwell's
theory.[68]
However
much he
may
have
regretted
the resultant
dualism,
he
accepted
the need
to
employ a
mixture
of
both mechanical and
electromagnetic concepts
in his
work.[69]
Einstein
was
the first
physicist
to
argue
that the fundamental
concepts
of
both
mechanics and
electrodynamics require
drastic modification.[70]
Yet,
even
while
seeking ways
to
modify
them,
he
was
not
disposed
to jettison
the
concepts
of
either
theory
prematurely.[71]
He
recognized
the existence
of
a
broad
domain of
phenomena, to
the
understanding
of
which both theories continue to
provide
reliable
guidance.[72]
His work
on
molecular
forces,
the foundations
of
statistical
physics,
molecular
dimensions,
and Brownian motion all involve efforts to extend and
perfect
the
classical mechanical
(Galilei-Newtonian)
approach, including
its statistical exten-
sions.
Similarly,
his work
on
the
theory
of
relativity
and the
electrodynamics
of
moving
media
represent
efforts
to
extend and
perfect
Maxwell's
electrodynamics,
as incorporated
in
Lorentz's
electron
theory,
while
modifying
classical
mechanics
to
make it cohere with this
theory.
His
work
on
the
quantum hypothesis,
on
the other
hand,
consisted of demon-
strations
of
the limited
validity
of
both classical mechanics
and
Maxwell's
electro-
magnetic
theory,
and efforts
to
comprehend phenomena
that cannot be
explained
iert")
(Einstein
1913,
p. 1077).
For
a possible
influence
of
energetics
on
Einstein, see
the
edi-
torial
note,
"Einstein
on
the Foundations
of
Sta-
tistical Physics,"
p.
46.
[68]
See Einstein
1979,
pp. 18,
30,
32.
[69]
In 1914, Einstein
presumably was
recall-
ing
his
own acceptance
of
such
a
dualistic out-
look when he recalled that
"about
fifteen
years
ago, no one yet
doubted that
a
correct account of
the electrical,
optical,
and thermal
properties
of
bodies
was possible on
the basis
of
Galilei-New-
tonian mechanics,
applied
to molecular
mo-
tions,
and
of Maxwell's
theory
of
the electro-
magnetic
field"
("vor
etwa fünfzehn Jahren
zweifelte
man
noch nicht
daran,
daß
auf
der
Grundlage
der auf
die
Molekülbewegungen an-
gewendeten
Galilei-Newtonschen
Mechanik
und
der
Maxwellschen Theorie des
elektromag-
netischen Feldes
eine
richtige Darstellung
der
elektrischen,
optischen
und thermischen
Eigen-
schaften der
Körper
möglich
sei")
(Einstein
1914b,
p.
740).
For
a contemporary
critical comment
on
this
dualism,
see
Einstein 1905i
(Doc. 14),
pp.
132-
133;
for
a
later
one,
see
Einstein
1979,
p.
34.
[70]
See Einstein 1905i
(Doc. 14),
1906d
(Doc. 34).
[71]
In 1909 he noted
"that
it will
only
be
a
matter
of
a
modification
of
our present
theories,
and
not
a complete
abandonment
of them"
("Daß
es
sich
nur um
eine
Modifikation
unserer
heutigen
Theorien, nicht
um
ein
vollständiges
Verlassen derselben handeln wird")
(Einstein
1909b
[Doc. 56],
p.
192).
[72]
See Einstein 1907h
(Doc. 45),
pp.
372-
373,
for Einstein's
comments
on
the
range
of
ap-
plicability
of Maxwell's
equations.
In the Auto-
biographical Notes,
he commented:
"The
suc-
cess
of
the
theory
of
Brownian motion showed
again clearly
that classical
mechanics
always
yielded
reliable results when it
was
applied
to
motions in which the
higher
time
derivatives
of
the
velocity are negligibly
small"
("Der
Erfolg
der
Theorie
der Brown'schen
Bewegung
zeigte
wieder
deutlich,
dass die klassische Mechanik
stets dann
zuverlässige
Resultate
lieferte, wenn
sie
auf
Bewegungen angewandt
wurde,
bei
welchen die höheren zeitlichen
Ableitungen
der
Geschwindigkeit
vernachlässigbar
klein sind")
(Einstein 1979,
p.
46).