‘Long since convinced that the human race is infinitely perfectible, and that this process, a necessary consequence of the present state of knowledge and societies, can only be arrested by global physical setbacks, I viewed the task of hastening this progress as one of the most precious occupations, one of the first duties of one who has fortified his reason by study and reflection’ (O.C. I: 574). These words were written in July 1793 by the marquis de Condorcet while in hiding under sentence of death from the Jacobin Terror, separated from his wife and small daughter, and engaged in preparing a grand work entitled Tableau historique des progrès de l’esprit humain, of which he intended the Esquisse, meaning ‘sketch’, here presented in translation, as a ‘prospectus’. Of the projected work there are only fragments and notes (such as the definitions of ‘liberty’ and ‘revolutionary’ included here), for within months he was found dead in a country prison at the age of fifty.

Denounced by Robespierre as ‘a timid conspirator, viewed with contempt by all parties, ceaselessly working to obscure the light of philosophy with the perfidious hodgepodge of his mercenary rhapsodies’, he was the last of the great French Enlightenment philosophes: at once academician, encyclopedist and revolutionary. He was a mathematician and one of the leading statisticians of his day, an economist, a philosopher and a politician. He made profound and lasting contributions to the analysis of voting and the paradoxes of social choice and thereby to understanding deep and still unsolved problems for the practice of democracy – how to ascertain ‘the will of the people’ – contributions that are still debated and built upon today. As an economist he was both a critic of the stifling, corrupt and arbitrary economic regulations of his time and a proponent of detailed reforms for the constitution of a competitive economic order. As a philosopher he held distinctive and still controversial views about the probabilistic character of human knowledge, about the relations between reason and moral sentiments, and about both the conflict and connectedness of values. He identified the distinctive features of modern despotism before Alexis de Tocqueville and the contrast between ancient and modern liberty before Benjamin Constant.