The influence of the subversive and rationalistic thinkers in bringing about the events of 1789 has been variously estimated by historians.  The truth probably lies in the succinct statement of Acton that “the confluence of French theory with American example caused the Revolution to break out” when it did.  The theorists aimed at reform, not at political revolution; and it was the stimulus of the Declaration of Rights of 1774 and the subsequent victory of the Colonies that precipitated the convulsion, at a time when the country had a better prospect of improvement than it ever had before 1774, when Louis XVI. came to the throne.  But the theories had prepared France for radical changes, and they guided the phases of the Revolution.  The leaders had all the optimism of the Encyclopaedists; yet the most powerful single force was Rousseau, who, though he denied Progress and blasphemed civilisation, had promulgated the doctrine of the sovereignty of the people, giving it an attractive appearance of mathematical precision; and to this doctrine the revolutionaries attached their optimistic hopes. [Footnote:  It is interesting to observe how Robespierre, to whom the doctrines of Rousseau were oracles, could break out into admiration of the progress of civilised man, as he did in the opening passage of his speech of 7th May 1794. proposing the decree for the worship of the Supreme Being (see the text in Stephen, Orators of the French Revolution, ii. 391-92).] The theory of equality seemed no longer merely speculative; for the American constitution was founded on democratic equality, whereas the English constitution, which before had seemed the nearest approximation to the ideal of freedom, was founded on inequality.  The philosophical polemic of the masters was waged with weapons of violence by the disciples.  Chaumette and Hebert, the followers of d’Holbach, were destroyed by the disciples of Rousseau.  In the name of the creed of the Vicaire Savoyard the Jacobin Club shattered the bust of Helvetius.  Mably and Morelly had their disciples in Babeuf and the socialists.

A naive confidence that the political upheaval meant regeneration and inaugurated a reign of justice and happiness pervaded France in the first period of the Revolution, and found a striking expression in the ceremonies of the universal “Federation” in the Champ-de-Mars on 14th July 1790.  The festival was theatrical enough, decreed and arranged by the Constituent Assembly, but the enthusiasm and optimism of the people who gathered to swear loyalty to the new Constitution were genuine and spontaneous.  Consciously or subconsciously they were under the influence of the doctrine of Progress which leaders of opinion had for several decades been insinuating into the public mind.  It did not occur to them that their oaths and fraternal embraces did not change their minds or hearts, and that, as Taine remarked, they remained what ages of political subjection and one age of political literature had made them.  The assumption that new social machinery could alter human nature and create a heaven upon earth was to be swiftly and terribly confuted.