liv INTRODUCTION TO VOLUME
8
[16]Named
after the title
of
Einstein
and
Grossmann 1913
(Vol.
4,
Doc.
13).
[17]Einstein
1915h,
1915i
(Vol.
6,
Docs.
24, 25).
[18]The “Entwurf”
field
equations are covariant,
Einstein
claimed,
under
“justified”
coordinate
transformations
between coordinate
systems “adapted”
to
the metric field
(see
Doc.
18,
note
5,
for
a
definition
of
these
concepts). Levi-Civita, however,
found
a
“justified”
transformation
under
which
the
“Entwurf” field
equations
are
not covariant
(Doc. 67).
[19]See Vol. 6,
App.
B,
for
notes that
an
unknown auditor took
of
these
lectures.
[20]The
recent
discovery
of
page proofs
of
Hilbert 1915 has made
it clear
that Einstein’s
charge,
in
a
letter
to Zangger (Doc. 152),
was
not without
justification (see
Corry
et
al.
1997).
Traces
of
this
earlier version
of
Hilbert’s
paper can
be found in Doc.
140.
[21]As can
be
gathered
from Docs. 136 and 140.
[22]As
Einstein
pointed out,
he and Marcel
Grossmann
had,
in
fact,
considered
generally
covariant
field
equations very
close to the
ones
published
in
November
1915 three
years
earlier
(see
“Research
Notes
on a
Generalized
Theory
of
Relativity”
[Vol. 4,
Doc.
10];
see
Renn
and Sauer
1996 for
a pre-
liminary report on a new analysis
of
these
notes).
[23]See
the editorial
note,
“The
Einstein-De
Sitter-Weyl-Klein Debate,”
pp.
351-357, for
a more
detailed discussion
of
the debate
and
of
the role
of
Hermann
Weyl
and Felix Klein in the clarification
of
some
of the
issues
that
were
raised.
[24]Einstein 1914o
(Vol. 6,
Doc.
9)
and Einstein
1916e
(Vol. 6,
Doc.
30).
[25]A
discussion
of
“justified”
transformations and the hole
argument
in
a
letter
to Lorentz
of
Jan-
uary
1915 sheds
some
light
on
the
reasoning
behind this claim
(Doc. 47).
[26]See
Doc.
465,
note
12,
for discussion
of
this
paper.
[27]Einstein
1916e
(Vol. 6,
Doc.
30),
p.
776.
[28]As
Einstein
hastened
to add,
it still follows
from
the
relativity principle
in its
new
form that the
laws
of
nature find
their
only
natural
expression
in
generally
covariant
equations (Einstein 1918f
[Vol.
7,
Doc.
4],
p.
241).
[29]The point-coincidence
argument can
be
found
in
a
letter to Besso
(Doc. 178)
and in
two
letters
to
Ehrenfest
(Docs.
173 and
180),
who showed at
least
one
of
them to
Lorentz
(see
Doc.
183).
[30]Einstein
1914o
(Vol.
6,
Doc.
9),
pp.
1031-1032.
See also
Vol. 4,
Doc.
14, [pp.
36-37],
[31]See
also
a
letter
to
Eduard Hartmann
of
April
1917
(Doc. 330).
[32]This
is
suggested
by
Einstein’s further
elaboration of
the
equivalence principle
in Einstein
1918f
(Vol.
7,
Doc.
4).
He
emphasizes
that
it
follows
from
the
principle (and
the results
of
special
relativity)
that
the metric tensor
determines
both the
inertial structure
and
the
gravitational
field.
[33]Einstein 1912d
(Vol. 4,
Doc.
4).
[34]See
Einstein
and
Grossmann
1914b
(Vol.
6,
Doc.
2)
and Einstein 1914o
(Vol.
6,
Doc.
9)
for
the
“Entwurf”
theory;
and Einstein 1916o
(Vol. 6,
Doc.
41)
for the
theory
of November
1915.
[35]This point
is also
emphasized
in letters
to Besso
(Doc. 270),
De Sitter
(Doc. 273),
Lorentz
(Doc.
276),
and Hermann
Weyl
(Doc. 278).
[36]Of
particular
interest
is
a
brief
exchange
in
March
1918
following
a
letter
(Doc. 480),
in which
Einstein
objected
to
the
discussion
of
Einstein 1916o
(Vol.
6,
Doc.
41)
in
Klein, F.
1917.
[37]Levi-Civita
(Doc. 375)
and Friedrich Kottier
(Doc. 495).
Rudolf
Förster informed Einstein
of
his
independent discovery
of
these identities
(Doc. 463).
Einstein
did
not comment
on
this result in
his
reply.
[38]See
Doc.
503, note
8,
for
detailed references.
[39]See
Doc.
487,
note
11,
for detailed references.
[40]See,
in
particular,
Einstein
1918g
(Vol. 7,
Doc.
9).
[41]See, e.g.,
Misner
et
al.
1973,
pp.
466-468
[42]See
Doc.
472,
note
3,
for
a more
detailed
discussion of
this
theory.
[43]Weyl’s
theory
is also discussed in
correspondence
with
Besso,
with
Weyl’s
student Walter Däl-
lenbach,
and with Paul
Bernays, a
Zurich
mathematician
who
spent some
time in
Göttingen
in 1918.
[44]Hermann
Weyl
to Carl
Seelig,
19
May
1952,
quoted
in
slightly
edited
form in
Seelig
1960,
pp.
274-275.