248 THE SOCIAL THEORY OF GEORG SIMMEL
accumulation of money in centers and the resulting increase
 in individual contacts—all these phenomena which
are the immediate outcome of the money economy have
increased the changes in the contents of life so greatly that
the preceding natural economy seems static by comparison.
 But the full significance of money as such for the
tempo of life, apart from the technical results of its introduction,
 can be shown only by a further consideration.
An analysis of the concepts of persistence and change
shows a double contradiction, If we view the world with
regard to its substance, we are led to a concept of an unchangeable
 reality which, because it excludes all increase
or decrease, gives to matter the character of absolute
persistence. If, on the other hand, we regard the form of
this substance, then the persistence is completely dissolved.
 One form changes incessantly into another, and
the world seems a perpetuum mobile. This is the double aspect
 of cosmological existence, which is often given a metaphysical
 significance. On another empirical plane, however,
 the opposition between persistence and mobility is
divided differently. There we see the persistence of forms
during a certain period, while the real elements of which
they are composed are in constant movement. The rainbow
 persists, although the water particles change; the organic
 and the social forms persist, although their elements
come and go; and even in inorganic objects there persist
only the relations and the reciprocities of their minute elements,
 while the latter are in constant movement. In this
case reality itself is in constant flux, but, as the latter cannot
 be seen, the forms and constellations of its movements
solidify in the phenomena of persistent objects.
Apart from these two contradictions which result from
the application of the ideas of persistence and movement
to the conceived world, there exists a third. Persistence