Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-02-03
Einstein's New Theory

| this theory discarded the absolute char
acter of the conception of the stimuli
| taneity of two spatially separated
events. Well known is also the courage
of despair with which some philosophers
still defend themselves in profusion OF
proud but empty words against this
| simple theory.
On the other hand. the services rem
dered by the special theory of relatively
to its parent. Maxwell's theory of the
electromagnetic field, are less ade-
quately recognized. Up to that time the
electric field and the magnetic field
were regarded as existing separately
even II close causal correlation be-
tween the two types of field was pro-
vided by Maxwell's field equations. But
the special theory of relatively showed
that this casual correlation corresponds
to an essential identity of the two types
Of field. In fact, the same condition of
space. which in one coordinate system
appears as pure magnetic field, APP
pears simultaneously in another co-or-
dinate system in relative motion as an
electric field and vice versa. Relation
ship of this kind displaying an identity
between different conceptions which
therefore reduce the number of indie
pendent hypothesis and concepts of
field theory and heighten its logical
self-containedness are a characteristic
feature Of the theory of relatively. For
instance. the special theory also indi-
Gated the essential identity of the con-
ceptions inertial mass and energy. This
is all generally known and is only men,
ton here in order to emphasize the
unitary tendency which dominates the
whole development of the theory.
Euclidian Basis is Abandoned.
We now turn to the second stage in
the development of the theory of rela-
tivity, the So-called general theory of
RELATIVELY. This theory also starts from
fact OF experience which till then had
received no satisfactory Interpretation.
the equality of inertial and gravitational
mass or. in other words. the fact known
since the days of Calico and Newton
that all bodies fall with equal accelera-
ton in the earth's gravitational field.
The theory uses special theory as its
basis, and at the same time modif1es
it: the recognition that there is no
state of motion whatever which is
physically privileged-that is, that not
only velocity but also acceleration are
without absolute signif1cance-forms the
starting point of the theory It then
compels much more profound modi-
tication of the conceptions of space and
sine than were involved in the special
theory. For even ii the special theory
forced us to fuse space and time to-
gether to an invisible four dimensional
continuum. yet the Euclidian char
acter of the continuum remained es-
sentially intact in this theory. In the
general theory of relatively this hypoth-
esis regarding the Euclidian character
Of our space-time continuum had to be
abandoned and the latter given the
structure of a so-called Riemannian
space. Before we attempt to under
stand what these terms mean let us
recall what this theory accomplished.
Gravitation and Inertia Are Fused.
It furnished an exact field theory of
gravitation and brought the latter into
a fully determinate relationship to the
metrical properties of the continuun.