This superiority forms indeed the minor premiss in the general argument by which he confuted the commonly received opinion as to the populousness of ancient nations.

He insisted on the improvements in art and industry, on the greater liberty and security enjoyed by modern men.

"To one who considers coolly on the subject," he remarked, "it will appear that human nature in general really enjoys more liberty at present in the most arbitrary government of Europe than it ever did during the most flourishing period of ancient times." [Footnote: The justification of this statement was the abolition of slavery in Europe.] He discussed many of the problems of civilisation, especially the conditions in which the arts and sciences flourish, [Footnote: Essay on the Rise of Arts and Sciences.] and drew some general conclusions, but he was too sceptical to suppose that any general synthesis of history is possible, or that any considerable change for the better in the manners of mankind is likely to occur.

[Footnote: Cf.

Essay on the Idea of a Perfect Commonwealth, ad init.] The greatest work dealing with social problems, that Britain produced in the eighteenth century, was Adam Smith's Wealth of Nations, and his luminous exposition of the effects of the division of labour was the most considerable contribution made by British thinkers of the age to the study of human development.