There was, indeed, one question which caused some embarrassment to believers in Progress.  The increase of wealth and luxury was evidently a salient feature in modern progressive states; and it was clear that there was an intimate connection between the growth of knowledge and the growth of commerce and industrial arts, and that the natural progress of these meant an ever-increasing accumulation of riches and the practice of more refined luxury.  The question, therefore, whether luxury is injurious to the general happiness occupied the attention of the philosophers. [Footnote:  D’Holbach, ib. iii. 7; Diderot, art.  Luxe in the Encylopaedia; Helvetius, De l’esprit, i. 3.] If it is injurious, does it not follow that the forces on which admittedly Progress depends are leading in an undesirable direction?  Should they be obstructed, or is it wiser to let things follow their natural tendency (laisser aller les choses suivant leur pente naturelle)?  Voltaire accepted wealth with all its consequences.  D’Holbach proved to his satisfaction that luxury always led to the ruin of nations.  Diderot and Helvetius arrayed the arguments which could be urged on both sides.  Perhaps the most reasonable contribution to the subject was an essay of Hume.

4.

It is obvious that Rousseau and all other theorists of Regress would be definitely refuted if it could be proved by an historical investigation that in no period in the past had man’s lot been happier than in the present.  Such an inquiry was undertaken by the Chevalier de Chastellux.  His book On Public Felicity, or Considerations on the lot of Men in the various Epochs of History, appeared in 1772 and had a wide circulation. [Footnote:  There was a new edition in 1776 with an important additional chapter.] It is a survey of the history of the western world and aims at proving the certainty of future Progress.  It betrays the influence both of the Encyclopaedists and of the Economists.  Chastellux is convinced that human nature can be indefinitely moulded by institutions; that enlightenment is a necessary condition of general happiness; that war and superstition, for which governments and priests are responsible, are the principal obstacles.

But he attempted to do what none of his masters had done, to test the question methodically from the data of history.  Turgot, and Voltaire in his way, had traced the growth of civilisation; the originality of Chastellux lay in concentrating attention on the eudaemonic issue, in examining each historical period for the purpose of discovering whether people on the whole were happy and enviable.  Has there ever been a time, he inquired, in which public felicity was greater than in our own, in which it would have been desirable to remain for ever, and to which it would now be desirable to return?