The population question has lost none of its importance, although it has somewhat changed its aspect. What Malthus called the preventive check has got such a hold of almost every country that modern economists and sociologists are concerned not so much with the question of an unlimited growth of population as with the regular and universal decline of the birth-rate. Everyone is further agreed that the causes must be social. It is not enough to say that the cause is a deliberate determination of parents to have no children or to have only a limited number. The question is, Why do they decide to have none or to limit their family to a certain number only? Why is this limitation more marked in France than elsewhere, and why is it more pronounced there to-day than it was say two or three generations ago? The special causes which apply to the France of to-day must somehow be discovered, and such causes may be expected to be less active elsewhere. It may be that Paul Leroy-Beaulieu is right when he claims that the progress of civilisation must always mean a declining birth-rate, because the fresh needs and desires and the extra expenditure which it necessarily involves are incompatible with the duties and responsibilities of maternity. It is possible that it diminishes as democracy advances, because the latter strengthens the telescopic faculty and quickens the desire to rise in the social scale as rapidly and as effectively as possible. M. Dumont, who advocates this view, has happily named it the law of capillarity. More precise causes are sometimes invoked, but they vary according to the particular school that formulates them. Le Play thinks that it is due to the practice of social inheritance. Paul Bureau takes it as a sign of the weakening of moral and religious belief, and of the growth of intemperate habits of every kind—alcoholism, debauchery, etc. Unfortunately none of the explanations given seem quite satisfactory, and a second Malthus is required to open up a new chapter in the history of demography.[312] II: RICARDO Next to Smith, Ricardo is the greatest name in economics, and fiercer controversy has centred round his name than ever raged around the master’s. Smith founded no school, and his wisdom and moderation saved him from controversy. Hence every economist, whatever his views, is found sitting at his feet straining to catch the divine accents as they fall from his lips.