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.