DOCS.
415,
416
DECEMBER
1917 423
415. To Otto
Marx[1]
Zurich
[Berlin],
22
December
1912.
[1917][2]
Marx had
requested
Einstein’s assistance in
solving
a
problem
with
an
airplane.
...
I
was
delighted
with
your gorgeous
and
witty gift.
When
looking
through
the
fine
album,
I
shall
think
back often with amusement
about
your
...
and
my
escapade
into the
realm
of
praxis
...[3]
With best
regards
and
good
wishes
for
the
holidays, yours truly,
A.
Einstein.
416. To
Gustav Mie
[Berlin,]
22
December 1917
Highly
esteemed
Colleague,
Cordial
thanks
for
sending
me
your very interesting lectures,
which
I
have
studied
more
than
once already.[1]
Our
remaining
differences
of
opinion
are
rela-
tively insignificant.
The main distinction consists
in
that
I do
not
believe
in
the
“flat basic
shape”
of the world continuum.
If it
were
to
hold,
your suggested
coor-
dinate
choice
through
orthogonal projection on
R4
in
a
10-dimensional Euclidean
space
would be
very
reasonable
(provided
that
the
hyperbolic
character
did
not
add
difficulties).[2]
I
do
not
believe, though,
that the universe
is
essentially empty
and flat
and,
while
extending
into
infinity,
is filled
with
matter
only
within
a
finite
region.
That smacks
of
a
geocentric
interpretation.
Many already, Seeliger
among
them,
wanted
to
have
nothing
to
do with
that.[3] I cannot
believe
that the
guv’s
(hence
also
inertia)
are
determined
not
only mainly by
boundary
conditions
at
infinity
but
also
a
bit
by
the
remaining
matter,
in addition. In
my opinion,
the
guv's
are
determined
entirely by
the
matter,
insofar
as
they
do
not
have
to
remain
undetermined
because
of
the arbitrariness
of
the
choice
of
coordinates.[4]
I
do not
agree
with
the
reflections
on
the
necessity
of
the
existence of
preferred
coordinate
systems.
They
can
easily
cause
confusion.
We
must discuss all these
things one
day
at
our
leisure and in
private,
not
in
the
presence
of Philistines
(Lecher).[5]
I
may
be
a
democrat,
but
in these
subtle
matters
I
think little
of
the
opinion
of
the
majority.
I
am
sending you
a
paper
which
I
would like
you
to read in
the
meantime
so
that
you
also become