A more important difference between the two thinkers is connected with the different circumstances in which they wrote.  Turgot did not believe in the necessity of violent changes; he thought that steady reforms under the existing regime would do wonders for France.  Before the Revolution Condorcet had agreed, but he was swept away by its enthusiasm.  The victory of liberty in America and the increasing volume of the movement against slavery—­one of the causes which most deeply stirred his heart—­had heightened his natural optimism and confirmed his faith in the dogma of Progress.  He felt the exhilaration of the belief that he was living through “one of the greatest revolutions of the human race,” and he deliberately designed his book to be opportune to a crisis of mankind, at which “a picture of revolutions of the past will be the best guide.”

Feeling that he is personally doomed, he consoles himself with brooding on the time, however remote, when the sun will shine “on an earth of none but freemen, with no master save reason; for tyrants and slaves, priests and their stupid or hypocritical tools, will all have disappeared.”  He is not satisfied with affirming generally the certainty of an indefinite progress in enlightenment and social welfare.  He sets himself to think out its nature, to forecast its direction, and determine its goal, and insists, as his predecessors had never done, on the prospects of the distant future.

4.

His ambitious design is, in his own words, to show “the successive changes in human society, the influence which each instant exerts on the succeeding instant, and thus, in its successive modifications, the advance of the human species towards truth or happiness.”  Taken literally, this is an impossible design, and to put it forward as a practical proposition is as if a man were to declare his intention of writing a minute diary of the life of Julius Caesar from his birth to his death.  By stating his purpose in such terms, Condorcet reveals that he had no notion of the limitations which confine our knowledge of the past, and that even if he had conceived a more modest and practicable programme he would have been incapable of executing it.  His formula, however, is worth remembering.  For the unattainable ideal which it expresses reminds us how many periods and passages of human experience must always remain books with seven seals.

Condorcet distinguished ten periods of civilisation, of which the tenth lies in the future, but he has not justified his divisions and his epochs are not co-ordinate in importance.  Yet his arrangement of the map of history is remarkable as an attempt to mark its sections not by great political changes but by important steps in knowledge.  The first three periods—­the formation of primitive societies, followed by the pastoral age, and the agricultural age—­conclude with the invention of alphabetic writing in Greece.  The fourth is the history of Greek thought, to the definite division of the