His progress in the improvement and exercise of his mental and corporeal faculties has been irregular and various, infinitely slow in the beginning, and increasing by degrees with redoubled velocity; ages of laborious ascent have been followed by a moment of rapid downfall; and the several climates of the globe have felt the vicissitudes of light and darkness.

Yet the experience of four thousand years should enlarge our hopes and diminish our apprehensions; we cannot determine to what height the human species may aspire in their advances towards perfection; but it may safely be presumed that no people, unless the face of nature is changed, will relapse into their original barbarism." [Footnote: Decline and Fall of the Roman Empire, ch.xxxviii.ad fin.] But Gibbon treats the whole subject as a speculation, and he treats it without reference to any of the general principles on which French thinkers had based their theory.

He admits that his reasons for holding that civilisation is secure against a barbarous cataclysm may be considered fallacious; and he also contemplates the eventuality that the fabric of sciences and arts, trade and manufacture, law and policy, might be "decayed by time." If so, the growth of civilisation would have to begin again, but not ab initio.

For "the more useful or at least more necessary arts," which do not require superior talents or national subordination for their exercise, and which war, commerce, and religious zeal have spread among the savages of the world, would certainly survive.
These remarks are no more than obiter dicta but they show how the doctrine of Progress was influencing those who were temperamentally the least likely to subscribe to extravagant theories.
4.
The outbreak of the French Revolution evoked a sympathetic movement among English progressive thinkers which occasioned the Government no little alarm.

The dissenting minister Dr.Richard Price, whose Observations on Civil Liberty (1776), defending the action of the American colonies, had enjoyed an immense success, preached the sermon which provoked Burke to write his Reflections; and Priestley, no less enthusiastic in welcoming the Revolution, replied to Burke.