THE EEGULATION OF NUMBEES 201 



the population is not large enough to bring all returns up to this 

 point, returns will be less than they might be, and the remedy is 

 increase of population ; if, on the other hand, population is so 

 great that the point has been passed, returns are again less than 

 they might be, and the remedy is decrease of population.' ^ 



This idea of an optimum number is one which can be developed 

 in great detail. (^It is only necessary here to notice that when, 

 as in the higher economic stages, the arts of production on the 

 one hand are improving and the habits and so on of any people 

 are on the other hand constantly altering, the most desirable 

 density is in consequence frequently changing. In the lower 

 stages, when progress in skill is slow and social conditions more 

 or less stationary, the optimum number may remain about the 

 same over long periods of time. Further, with regard to progress 

 in skill, inasmuch as the productivity of labour is enhanced by 

 every improvement in the arts of production, the result of such 

 progress will be that the return per head will, as a rule, increase. 

 Such progress will thus, as a rule, allow of a larger population 

 which will have a larger income per head/) 



This idea of an optimum density of population is wholly 

 different to that put forward by Malthus. To him the problem 

 was one of the relative increase of population and of food ; with 

 us it is one of the density of population and of the productiveness 

 of industry. To Malthus the position was much the same in all 

 ages ; in his view population, except under unusual circumstances, 

 had in any country at any given time always increased up to the 

 limit of subsistence, and was in process of being checked — chiefly 

 by vice and misery. In the modern view increase in skill has 

 brought to an increasingly dense population a larger income per 

 head. The chief cause of the largest possible income not on all 

 occasions being reached is that at times the density of population 

 increases beyond the optimum number for the given conditions, 

 though at other times the failure of population to reach the 

 desirable level may produce the same result. 



Though the problem of diminishing returns was being discussed 

 as the successive editions of the Essay appeared, the idea was 



* Cannan, Wealth, p. 68. This is frequently misunderstood. Thus we read that 

 ' occasionally, from accidental circumstances, England was for a short time 

 under-populated, and these were the jjeriods when . . . the labourer was well o£E ' 

 (Inge, loc. cit., p. 90). The evidence alluded to would tend to show that there was 

 previously a condition of over-population. In any case a people as a whole is not 

 better off when under-j»opulation arises. 



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