LAWS OF NATURE IN CIVILIZATIONS        291
tween the different lengths of the successive intervals that is common
to all the divers examples of this series of intervals in the histories of
different civilizations.
'Laws of Nature* in the Growths of Civilizations
When we turn our attention from Social Disintegration to Social
Growth, we shall recollect our finding, at a previous stage of this Study,1
that Growth, as well as Disintegration, exhibits a cyclically rhythmic
movement. Growth takes place whenever a challenge evokes a successful
response that, in turn, evokes a fresh challenge that is not identical with
the preceding challenge by which the creatively provocative response
has been elicited. We have not found any intrinsic reason why this pro-
cess should not repeat itself ad infinitum, even though a majority of the
civilizations that had come to birth down to the time of writing might
have failed, as a matter of historical fact, to maintain their growth by
managing, for more than a small number of times in succession, to make
a response that had been both an effective answer to the challenge that
had called it forth and at the same time a fruitful mother of a new challenge
demanding a new response.
We have seen, for example,2 that in the history of the Hellenic Civili-
zation the initial challenge of an anarchic barbarism, which was the
legacy of the break-up of an antecedent Minoan Civilization's universal
state, evoked an effective response in the shape of a new political institu-
tion, the city-state, which was perhaps created by ship's companies of
refugees who were cast up upon the eastern shores of the Aegean Sea in
the course of a post-Minoan interregnum (durabat circa 1425-1125 b.c.) j
and we have noticed in the same context that the very success of this re-
sponse to a challenge on the political plane evoked, in its turn, a fresh
challenge, this time on the economic plane, in the shape of the rising
pressure of a population whose natural increase was now no longer being
kept in check by battle, murder, and sudden death as drastically as it had
been before the return of law and order accompanying the rise of city-
states.
This challenge presented to the Hellenes by the pressure of popula-
tion upon the means of subsistence, in a physical environment in which
Nature set rigid limits to the increase of agricultural production, evoked,
as we have seen, a number of alternative responses of unequal efficacy.
There was the disastrous Spartan response of conquering the fields of
the Spartans' Messenian next-door-neighbours within their common
Hellenic homeland; there was the temporarily effective Corinthian and
Chalcidian response of winnmg new fields for Hellenes to plough over-
seas in lands wrested from more backward peoples in the Western Basin
of the Mediterranean; and there was the permanently effective Athenian
response of increasing the aggregate productivity of this enlarged Hellenic
World—after its geographical expansion had been brought to a halt by
the concerted resistance of Phoenician and Tyrrhenian competitors3—
1	In III. iii. 119-27.
 2	Ibid., pp. iao-2. See also I. i. 24-26: II. ii. 36-49; and III. iii. 139-40 and 197-8.
 3	See I. i. 24-25; II. ii- 38-42; HI. iii. 122; and IX. via. 436.