VARIABILITY OF RATE OF CULTURAL CHANGE 349
goes, that human affairs are recalcitrant to laws of Nature In the Time-
dimension at least. We cannot, however, take the variability of the rate
of social change for granted.

In studying the phenomena of social disintegration, we have found
that the disintegration-process has run a regular course which it has fol-
lowed uniformly in a dozen divers instances up to date. It has invariably
opened with a Time of Troubles which has invariably passed over into
a universal state; the transit from the outbreak of the Time of Troubles,
signifying the civilization's breakdown, to the break-up of the universal
state, signifying the civilization's dissolution, has invariably been accom-
plished within the compass of three and a half revolutions of a Rout-
and-Rally Cycle; and this process has invariably taken a mininiurn
period of eight centuries to work itself out, while its maximum period
has never been as much as eleven hundred years. Moreover, the rules of
this process have been proved by the apparent exceptions.

When a universal state has been interrupted, before it has completed
its regular Time-span of some four hundred years' duration, by the
impact of an alien body social, the assaulted society has declined to
accept this intervention as a coup de grace and has obstinately prolonged
its own existence until it has found an opportunity to swing back into
the regular course of the disintegration-process by resuming its inter-
rupted universal state and, this time, abiding in it until this phase of
social experience has produced the full psychological effect that it has
been its function to produce according to the disintegration-process's
hitherto standard pattern. This process that has thus refused to allow an
external agency to prevent it from working itself out has likewise been
intractable to attempts to tamper with it from within. A universal state
that has completed the full normal period of its course may have per-
versely insisted on superfluously prolonging the tale of its years; but we
have seen that in every case it has broken up in the end, however long it
may have succeeded in postponing the evil day; and we have also seen
that in every case this illegitimate epilogue has been barren of creative
achievements. The vanity of all such attempts to set the laws of social
disintegration at defiance testifies to the inexorability of these laws so
impressively, and this law-bound process of social disintegration has
loomed so large in the history of the societies of the species 'civilizations*
during the first five or six thousand years of this species' existence, that
we are moved to ask ourselves whether the time-keeping propensity which
has thus displayed itself in the disintegration-process over a span of
something between a niinimum of about eight hundred and a maximum
of about a thousand years may not govern the histories of civilizations,
not only when these societies are disintegrating, but also when they are
still in growth.

If the tempo of History should indeed prove to be constant in all
circumstances, in the sense that the passage of each and every decade,
century, or millennium could be shown to generate a definite and
uniform quantum of psychological and social change, it would follow
that, if we knew the value either of a quantum in the psycho-social series
or of a span in the Time-series, we should be able to calculate the